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Title: The life of Isambard Kingdom Brunel, Civil Engineer
Author: Brunel, Isambard
Language: English
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[Illustration: IK Brunel Signature
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THE LIFE
OF
ISAMBARD KINGDOM BRUNEL,
CIVIL ENGINEER.
BY
ISAMBARD BRUNEL, B.C.L.,
OF LINCOLN’S INN;
CHANCELLOR OF THE DIOCESE OF ELY.
LONDON:
LONGMANS, GREEN, AND CO.
1870.
PREFACE.
I have not attempted to describe the events of my father’s life in
chronological order beyond the end of Chapter III., which brings down
the narrative to the close of 1835, the year in which the Act was
obtained for the Great Western Railway.
Chapter IV. contains a general account of my father’s railway works,
with the exception of the Bridges, which are described in Chapter VII.
The history of the Broad Gauge and of the trial of the Atmospheric
System on the South Devon Railway is given in Chapters V. and VI.
Chapters VIII.--XIII. contain an account of my father’s labours for the
advancement of Ocean Steam Navigation. It will be noted that these
chapters cover the same period as Chapters IV.--VII., namely, from 1835,
the year of the commencement of the Great Western Railway and the ‘Great
Western’ Steam-ship, to 1859, the year of his death, in which the
Saltash Bridge and the ‘Great Eastern’ were both completed.
Chapters VII. (on the Bridges) and XIV. (on the Docks) have been written
by Mr. William Bell, for many years a member of my father’s engineering
staff; and in regard to Chapter V. (on the Broad Gauge), I have to
acknowledge assistance rendered me by Mr. William Pole, F.R.S.
For the Note on the Carbonic Acid Gas Engine which follows Chapter I., I
am indebted to Mr. William Hawes; and for Chapter VI. (on the
Atmospheric System) to Mr. Froude, F.R.S.
I have also printed letters, written to me at my request, relating to
various incidents in my father’s life.
The assistance I received in the preparation of the chapters on Steam
Navigation from my friend the late Captain Claxton, R.N., has been
referred to in the note to p. 234.
I have throughout availed myself of my brother’s professional knowledge.
I have been compelled, in order to bring the work within the compass of
a single volume, to omit much that would otherwise have been inserted,
and I must therefore be held responsible for the general arrangement of
those parts which have been contributed by others, as well as for the
chapters which I have written myself.
Lastly, I desire gratefully to thank those friends who, by supplying me
with materials and revising the proof sheets, have helped me in my
endeavour to make this book, as far as possible, an accurate record of
my father’s life, written in the spirit of which he would have approved.
I. B.
18 DUKE STREET, WESTMINSTER:
_November_, 1870.
CONTENTS.
PAGE
LIST OF REPORTS AND OTHER ORIGINAL DOCUMENTS xvii
LIST OF ILLUSTRATIONS xxvii
CHAPTER I.
_EARLY LIFE._
A.D. 1806--1828.
Birth of Mr. Brunel, April 9, 1806--Sir Marc Isambard Brunel--The Block
Machinery--Mr. Brunel’s School Life--The Thames Tunnel--Sinking of the
Rotherhithe Shaft--Description of the Shield--Extracts from Sir Isambard
Brunel’s Journals from the Commencement of the Thames Tunnel to the date
of the Second Irruption of the River, January 12, 1828--_Note A_: The
Bourbon Suspension Bridges--_Note B_: Experiments with Carbonic Acid
Gas......1
CHAPTER II.
_THE CLIFTON SUSPENSION BRIDGE._
A.D. 1829--1853. ÆTATIS 24--48.
Origin of the Undertaking--The First Competition, November
1829--Description of Mr. Brunel’s Plans--Mr. Telford’s Decision as
Umpire--Mr. Telford’s Design--The Second Competition--Mr. Brunel
appointed Engineer, March 1831--Commencement of the Works, August
1836--Description of the Design--Abandonment of the Works,
1853--Formation of a New Company and Completion of the Bridge,
1864--_Note_: The Hungerford Suspension Bridge.....46
CHAPTER III.
_EARLY HISTORY OF THE GREAT WESTERN RAILWAY._
A.D. 1833--1835. ÆTATIS 27--30.
Sketch of the History of Railways in England prior to 1833--The Stockton
and Darlington--The Liverpool and Manchester--The London and
Birmingham--Proposed Railway between London and Bristol--Mr. Brunel
appointed Engineer, March 7, 1833--Survey of the Line--Unsuccessful
Application to Parliament in 1834--Successful Application in
1835--Reminiscences of Mr. Brunel, 1833-1835--Extract from Mr. Brunel’s
Diary, written at the close of 1835.....61
CHAPTER IV.
_RAILWAY WORKS._
A.D. 1835--1859. ÆTATIS 30--54.
Construction of the Great Western Railway--The Box Tunnel--The Bath and
Bristol Stations--The Paddington Station--The Great Western
Hotel--Branches and Extensions of the Great Western Railway--The Bristol
and Exeter Railway--Railways in Devonshire and Cornwall--Railways to
Basingstoke, to Weymouth, and to Salisbury--In South Wales--In
Ireland--In Italy--In India--Supervision of Works--Mr. Brunel’s
Engineering Staff--His Reputation as a Witness--Reminiscences of Mr.
Brunel, 1835-1838.....79
CHAPTER V.
_THE BROAD GAUGE._
Origin of the Ordinary Gauge of Railways--Adoption by Mr. Brunel of the
Broad Gauge on the Great Western Railway--Reasons for its Adoption--The
Permanent Way--Reports of Mr. Nicholas Wood and Mr. John Hawkshaw,
1838--_Extract from Report of Directors of Great Western Railway
Company_ (December 20, 1838)--Extension of the Broad Gauge System--Break
of Gauge--Royal Commission on the Gauge of Railways, 1845--_Letter of
Mr. Brunel on the Broad Gauge_ (August 6, 1845)--Gauge Act of 1846--The
Mixed Gauge--Report of Railway Commissioners, 1847--Northern Extensions
of the Great Western Railway--Advantages of the Broad Gauge--Partial
Abandonment of the Broad Gauge.....99
CHAPTER VI.
_THE ATMOSPHERIC SYSTEM._
A.D. 1840--1848. ÆTATIS 35--43.
Preliminary Observations--The South Devon Railway--Description of the
Atmospheric System--History of its Introduction prior to 1844--_Report
by Mr. Brunel, recommending its Adoption on the South Devon Railway_
(August 19, 1844)--Examination of this Report--Mr. Brunel’s Evidence
before the Select Committee on Atmospheric Railways, 1845--History of
the Application of the System on the South Devon Railway,
1844-1848--_Report on State of Works_ (August 28, 1847)--_Report on
Causes of Failure_ (August 19, 1848)--Abandonment of the System,
September 1848--_Note_: Comparison of Stationary and Locomotive
Power.....131
CHAPTER VII.
_RAILWAY BRIDGES AND VIADUCTS._
1. Brickwork and Masonry Bridges--Hanwell Viaduct--Maidenhead
Bridge--Flying Bridges--_Letter from Mr. Brunel on Bridge Construction_
(December 30, 1854)--2. Timber Bridges--Sonning Bridge--Bath
Bridge--Stonehouse Viaduct--Bourne Viaduct--St. Mary’s Viaduct--Viaducts
on the South Devon Railway--Ivy-bridge--Viaducts on the South Wales
Railway--Newport--Landore--Viaducts on the Cornwall Railway--St.
Pinnock--Viaducts on the West Cornwall and Tavistock
Railways--Preservation of Timber--3. Cast-iron Bridges--_Letter on Use
of Cast Iron_ (April 18, 1849)--Hanwell Bridge--Experiments on Cast-iron
Girders--_Extract from Letter to Secretary of Commission on Application
of Iron to Railway Structures_ (March 13, 1848)--4. Wrought-iron
Bridges--Girder Bridges--Experiments on Wrought-iron Girder--Opening
Bridges--Trussed Bridges--Newport Viaduct--Windsor Bridge--Chepstow
Bridge--Method of Sinking the Cylinders--Description of the Main
Truss--The Floating Operations--The Royal Albert Bridge at Saltash--The
Centre Pier--Description of the Superstructure--The Floating and Raising
of the Trusses--Opening of the Bridge by H. R. H. the Prince
Consort--_Note_: Experiments on Matters connected with Bridge
Construction.....171
CHAPTER VIII.
_STEAM NAVIGATION. THE ‘GREAT WESTERN’ STEAM-SHIP._
A D. 1835--1847. ÆTATIS 30--42.
Introduction to the Chapters on Steam Navigation--Formation of the Great
Western Steam-Ship Company--Commencement of the Building of the ‘Great
Western’--_Report on Selection of the Builders of the Engines_ (June 18,
1836)--Statements of Dr. Lardner on the probable Failure of a line of
Steam-ships between England and America--Voyage of the ‘Great Western’
to London--Completion of the Engines--Her return to Bristol--Fire on
Board, and Accident to Mr. Brunel--Voyage to New York--Comparison
between the Performances of the ‘Great Western’ and the
‘Sirius’--Subsequent History of the ‘Great Western’--_Note_: Dimensions
of the Ship and Engines.....231
CHAPTER IX.
_STEAM NAVIGATION. THE ‘GREAT BRITAIN’ STEAM-SHIP._
A.D. 1838--1847. ÆTATIS 33--42.
Commencement of the building of the ‘Great Britain’--_Report on the
Engines_ (June 13, 1839)--Experiments on the Screw Propeller--Its
Adoption in the ‘Great Britain’--Completion of the Ship--Her Voyage
across the Atlantic--Stranding of the ‘Great Britain’ in Dundrum
Bay--_Letter to Captain Claxton on the Condition of the ‘Great Britain’
and on the Means to be adopted for saving her_ (December 10,
1846)--_Report to the Directors on the same Subject_ (December 14,
1846)--Appointment of Captain Claxton to superintend the Execution of
Mr. Brunel’s Plans--_Letter to Captain Claxton on the Difficulties to be
overcome_ (December 29, 1846)--_Report enclosing Captain Claxton’s
Account of the Erection of the Breakwater_ (February 27, 1847)--_Report
on the Arrangements for Floating off the Ship_ (May 4, 1847)--Successful
Accomplishment of the Floating Operations--Subsequent History of the
‘Great Britain’--_Note_: Dimensions of the Ship and Engines.....246
CHAPTER X.
_STEAM NAVIGATION. INTRODUCTION OF THE SCREW PROPELLER INTO THE ROYAL
NAVY._
A.D. 1841--1844. ÆTATIS 36--39.
Appointment of Mr. Brunel to conduct Experiments for the Admiralty with
various Forms of the Screw Propeller, April 1841--Trials with the
‘Polyphemus’--Opposition to Mr. Brunel’s Experiments--Trials with the
‘Rattler’, October 1843--October 1844.....283
CHAPTER XI.
_STEAM NAVIGATION. THE ‘GREAT EASTERN’ STEAM-SHIP, FROM THE COMMENCEMENT
OF THE UNDERTAKING TO THE LAUNCH._
A.D. 1851--1857. ÆTATIS 46-62.
Introductory Observations--The Australian Steam Navigation
Company--_Statement of Mr. Brunel’s Project of a Line of large Ships_
(June 10, 1852)--Adoption of his Plans by the Eastern Steam Navigation
Company--_Extract from a Letter describing the Scheme_ (July 1,
1852)--_Letter to J. Scott Russell, Esq., on the Form and Dimensions of
the Great Ship_ (July 13, 1852)--_Report on Mode of Proceeding_ (July
21, 1852)--_Report on Enquiries Relating to the Draught and Form of the
Vessel_ (October 6, 1852)--_Report on the Proceedings of the Committee
appointed to consider Mr. Brunel’s Plans_ (March 21, 1853)--Tenders
invited for the Ship and Engines--_Report on Tenders_ (May 18,
1853)--Preparation of the Contracts and Specifications--_Extracts from
Mr. Brunel’s Memoranda_ (A.D. 1852, 1853, 1854)--_Letter on his Position
and Duties as Engineer of the Company_ (August 16, 1854)--_Letter on an
Article in a Newspaper_ (November 16, 1854)--_Report on the Undertaking_
(February 5, 1855)--Arrangements proposed for obtaining Astronomical
Observations--_Letter to G. B. Airy, Esq., Astronomer Royal_ (October 5,
1852)--Appointment of Mr. William Harrison to the Command of the
Ship--_Memorandum on the Management of the Great Ship_ (October
1855)--_Letter on the Duties of the Chief Engineer_ (March 19,
1857)--Suspension and Resumption of the Works.....289
CHAPTER XII.
_STEAM NAVIGATION. THE ‘GREAT EASTERN’ STEAM-SHIP. THE LAUNCH._
A.D. 1857, 1858. ÆTATIS 52.
Determination that the Ship should be launched broadside to the
River--And that the Launch should be slow--_Extracts from Mr. Brunel’s
Report of February 1855_--Reasons for the Adoption of Iron Sliding
Surfaces--Description of the Ways and Cradles--And of the Motive Power
provided for launching the Ship--_Memorandum on proposed Arrangements
for the Launch_ (September 26, 1857)--_Letter to Captain Harrison on
River Tackle_ (September 30, 1857)--_Letter on the Nature of the
Operations_ (October 23, 1857)--_Memorandum on general Arrangements and
intended Mode of Proceeding_ (October 30, 1857)--History of the Launch,
Nov. 3, 1857 to January 31, 1858--_Letter to the Directors_ (November
26, 1857)--_Report and Memorandum on the Launching Operations_ (December
17, 1857)--Floating the Ship--_Note A_: Experiments and Observations on
Friction--_Note B:_ Letter to W. Froude, Esq. (February 2, 1858).....340
CHAPTER XIII.
_STEAM NAVIGATION. THE ‘GREAT EASTERN’ STEAM-SHIP. COMPLETION AND
SUBSEQUENT HISTORY._
A.D. 1858, 1859. ÆTATIS 52-54.
A.D. 1859-1870.
Preparations for completing the Ship--Formation of the Great Ship
Company--Mr. Brunel’s Absence from England--Progress of the Works from
his Return to his last Illness--Voyage to Weymouth--Explosion of
Water-Heater--Storm at Holyhead--Description of the Ship--Her first
Voyage to New York, June 1860--Second Voyage to New York, May
1861--Voyage with Troops to Quebec, June 1861--Fracture of Rudder Head
and Destruction of Paddlewheels, September 1861--Voyages in
1862--Accident off Montauk Point, August 27, 1862--Voyages in
1863--Formation of the Great Eastern Steam-Ship Company--Remarks on the
History of the ‘Great Eastern’ previous to her Employment in laying
Submarine Telegraph Cables--Telegraph Expeditions of 1865 and
1866--French Cable Expedition of 1869--Voyage to Bombay and Aden, 1869,
1870--Concluding Remarks--_Note_: Dimensions of the Ship and
Engines.....392
CHAPTER XIV.
_DOCK AND PIER WORKS._
A.D. 1831--1859. ÆTATIS 26--54.
Monkwearmouth Docks, 1831--Bristol Docks--Floating Harbour,
1832--Proposed Works at Portishead--New Lock at Bristol, 1845--Bristol
Dock Gates--Plymouth Great Western Docks, 1847--Briton Ferry Docks,
1851--Brentford Dock, 1856--Pier at Milford Haven, 1857.....417
CHAPTER XV.
_MISCELLANEOUS WORKS._
The Great Exhibition of 1851--The Crystal Palace Water Towers,
1853--Polygonal Rifle, 1852--Gunnery Experiments, 1854--Floating
Gun-Carriage, 1854--Renkioi Hospital Buildings, 1855.....445
CHAPTER XVI.
_MR. BRUNEL’S PROFESSIONAL OPINIONS AND PRACTICE._
Scheme of the Chapter--Mr. Brunel’s Position in relation to the
Companies of which he was Engineer--_Letter on the Direction of Railway
Works in Italy_ (March 4, 1845)--_Letter on the Position of Joint
Engineer_ (October 16, 1843)--_Letter on the Position of Consulting
Engineer_ (December 30, 1851)--_Letter on the Position of the Engineer
in relation to the Contractors_ (May 26, 1854)--_Letters on the Position
of the Engineer in relation to the Directors_ (April 15, 1850, December
6, 1851, January 22, 1857)--Mr. Brunel’s Assistants--_Letters on
Interference of Directors with the Assistant Engineers_ (January 19,
1842, January 28, 1842, January 12, 1851)--Mr. Brunel’s Pupils--His
Relations with other Engineers--Inventors--_Letter in reply to an
Inventor_ (September 17, 1847)--Mr. Brunel’s Views as to State
Interference--_Letter on the Royal Commission on the Application of Iron
to Railway Structures_ (March 13, 1848)--_Letter on a Proposal to obtain
the Recognition in England of Decorations conferred at the Paris
Exhibition of 1855_ (February 9, 1856)--Mr. Brunel’s Opinion on the
Patent Laws--_Memorandum for Evidence before the Select Committee of the
House of Lords on the Patent Laws, 1851_--_Extract from Observations on
the Patent Laws, made by Mr. Brunel at a Meeting of the Society of
Arts,_ March 26, 1856.....474
CHAPTER XVII.
_PRIVATE LIFE._
Reminiscences of Mr. Brunel’s Private Life--Removal to 18 Duke Street,
Westminster--His Marriage, 1836--Special Constable in 1848--Mr. Brunel’s
Love of Art--His Journey to Italy, 1842--Accident with the
Half-Sovereign, 1843--Purchase of Property in Devonshire, 1847--His life
at Watcombe--The Launch of the ‘Great Eastern,’ 1857--Mr. Brunel’s
Failing Health--Journeys to Switzerland and Egypt, 1858--_Letter from
Philæ_ (February 12, 1859)--His last Illness--His Death, September 15,
1859--Funeral--Address of Joseph Locke, Esq., M.P., at the Institution
of Civil Engineers, November 8, 1859.....499
APPENDIX I.
Report to the Directors of the Great Western Railway on the Broad Gauge,
&c. (August 1838).....525
APPENDIX II.
Report to the Directors of the Great Western Steam-Ship Company,
recommending the Adoption of the Screw Propeller in the ‘Great Britain’
Steam-ship (October 1840).....539
INDEX.....559
LIST
OF
REPORTS AND OTHER ORIGINAL DOCUMENTS.
PAGE
1. Extract from Mr. Brunel’s Diary (December 26, 1835).....78
2. Letter on the Box Tunnel (June 21, 1842).....81
3. Extract from Report to Directors of the Great Western Railway Company
on Break of Gauge (December 13, 1838).....105
4. Extract from Report to Directors of the Great Western Railway Company
on the Permanent Way (February 1837).....109
5. Letter on various Points relating to the Broad Gauge (August 4,
1845).....120
6. Extract from Letter on Atmospheric System (April 8, 1844).....137
7. Report to the Directors of the South Devon Railway Company,
recommending them to adopt the Atmospheric System (August 19,
1844).....138
The question had been frequently considered by him (p. 138)--Stationary
power is cheaper and otherwise better than locomotive power (p.
138)--The Atmospheric System is a good, economical mode of applying
stationary power (p. 138)--Reasons for considering it applicable to the
South Devon Railway (p. 139)--In the construction of the line (p.
140)--In the subsequent working (p. 141).
8, 9. Letters on giving Evidence before the Select Committee of the
House of Commons on the Atmospheric System (March 31, 1845; April 3,
1845).....145
10. Report to the Directors of the South Devon Railway on the State of
the Atmospheric Apparatus (August 27, 1847).....149
Regret at postponement of working (p. 149)--Which has been caused by
delay in completion of the engines (p. 149)--Experimental trains have
run (p. 149)--Difficulties have exceeded all just anticipations (p.
150).
11. Report to a Committee of the Directors of the South Devon Railway
Company on the Causes of the Failure of the Atmospheric System (August
19, 1848).....159
The first difficulty has been in the stationary engines, which have
consumed an excessive amount of fuel (p. 159)--The difficulties in the
working of the longitudinal valve have been more numerous (p. 161)--The
principal evil might be remedied in a new valve (p. 162)--An extension
of the system beyond Newton cannot be recommended (p. 162)--The delay in
obtaining the telegraph has been a great disappointment (p. 163).
12. Letter on the Design of Engineering Works (December 30,
1854).....178
13. Extract from Letter on the Use of Cast Iron in Bridge Construction
(April 18, 1849).....190
14. Extract from Letter on the same Subject (March 13, 1848).....192
15, 16, 17. Extract from Letters on Bridges of Large Spans (January 31,
1852; December 1, 1852; May 30, 1854).....212
18. Extract from Report on the Cornwall Railway as to making the Saltash
Bridge for a Single Line (February 5, 1852).....214
19. Report to the Directors of the Great Western Steam-Ship Company on
the Selection of the Builders of the Engines for the ‘Great Western’
Steam-ship (June 18, 1836).....235
Every means must be taken to secure the best engines possible in this
the boldest attempt yet made (p. 235)--The peculiar conditions required
in these engines (p. 235)--They must, as far as is possible, be perfect
in all their details from the moment of their completion (p. 235)--The
machinery required is by no means an ordinary steam-engine (p.
236)--Modifications necessary in designing engines of so large a size
(p. 236)--Reasons based on these considerations for preferring Messrs.
Maudslay and Field as builders of these engines (p. 236).
20. Letter on the Engines for the ‘Great Britain’ Steam-ship (June 12,
1839).....249
Both the plans of Messrs. Maudslay and Field and Mr. Humphrys are
adapted to the case, and the choice will depend upon the relative cost
and advantages of forming an establishment to build the engines, and
that of having the skill of experienced manufacturers (p. 249).
21. Letter to T. R. Guppy, Esq., on the Construction of Iron Ships
(August 3, 1843).....259
22. Extract from Letter on the ‘Great Britain’ Steam-ship (December 11,
1844).....261
23. Letter to Captain Claxton on the State of the ‘Great Britain’
Steam-ship (December 10, 1846).....264
24. Report on the Condition of the ‘Great Britain’ Steam-ship when
stranded in Dundrum Bay (December 14, 1846).....267
The ship is, apart from mere local damage, perfectly sound, which would
not have been the case had she been built of timber (p.
267)--Description of her injuries (p. 268)--Consideration of the best
means of recovering the property invested in her--It would not be
profitable to break her up (p. 268)--How, then, is the vessel to be got
into port? (p. 269)--This question is secondary to that of how she is to
be preserved until she can be removed (p. 269)--A stiff timber
breakwater would not stand, even if it could be safely constructed (p.
269)--The best plan is to form under the stern and along the exposed
side of the ship a mass of fagots (p. 270)--And in order to preserve the
ship, this must be done without delay (p. 270)--As to floating her off,
she should be lifted and made water-tight (p. 271)--But she must first
be preserved (p. 272).
25. Letter to Captain Claxton on the Breakwater (December 29,
1846).....272
26. Report enclosing Captain Claxton’s Account of the Proceedings at
Dundrum (February 27, 1847).....273
Success achieved by Captain Claxton in constructing the breakwater of
fagots (p. 273)--Introduction by him of several important alterations
and improvements in the plans proposed (p. 274).
27. Report on the proposed Means of Floating the ‘Great Britain’
Steam-ship (May 4, 1847).....278
The ship has been successfully protected and lifted, and made
water-tight, so that the operation of floating by camels becomes more
practicable (p. 279)--The Directors would do well to call in Mr. Bremner
to advise them (p. 280).
28. Extract from Letter relating to Proceedings at the Admiralty as to
the Screw Propeller (July 8, 1842).....283
29. Extract from Letter on the same Subject (August 6, 1842).....286
30. Statement of Project for a Line of large Steam-ships (June 10,
1852).....292
The principle advocated is that of making the vessel large enough to
carry her own coal for the voyage, just as the ‘Great Western’
steam-ship did in 1838 (p. 292)--The size being limited only by the
extent of demand for freight, and by the circumstances of the ports to
be frequented (p. 292).
31. Extract from Letter describing the Project of the Great Ship (July
1, 1852).....293
32. Letter to J. Scott Russell, Esq., on the Form and Dimensions of the
Great Ship (July 13, 1852).....294
33. Report to the Directors of the Eastern Steam Navigation Company on
mode of Proceeding (July 21, 1852).....296
34. Report on Enquiries relating to the Draught and Form of the Great
Ship (October 6, 1852).....297
35. Report on the Dimensions of the Great Ship (March 21, 1853).....299
36. Report on the Tenders for the Ship and Engines (May 18,
1853).....301
A short specification was drawn up for the engines, and detailed
drawings and specifications for the ship (p. 301)--Tenders have been
received for the engines from Mr. J. Scott Russell, Messrs. Watt and
Co., and Mr. Humphrys (p. 302)--After frequent communications with these
gentlemen, Messrs. Watt and Co.’s designs are preferred for the screw
engines, which will be the largest yet made, and on which will mainly
depend the performances of the ship (p. 302), and Mr. J. Scott Russell’s
for the paddle engines (p. 302)--As regards a tender for the ship, after
communications with several parties, the result is a tender from Mr. J.
Scott Russell (p. 303).
37. Extracts from Mr. Brunel’s Memoranda relating to the ‘Great Eastern’
Steam-ship (July 11, 1852, to November 18, 1853).....304
July 11, 1852: Dimensions of the ship (p. 304)--Division of power
between the screw and paddle engines (p. 305)--Every known means must be
adopted to ensure efficiency (p. 305)--Jacketing of steam pipes, &c. (p.
305). July 17, 1852: Conference with Mr. Field as to division of power
between the screw and paddle engines (p. 305)--Pressure of steam (p.
305)--Nothing uncertain must be risked (p. 305)--Jacketing (p. 305).
July 19, 1852: Strong bulkheads every 30 feet or thereabouts, and the
main ribs, and even at least two main deck beams, to be longitudinal,
instead of transverse (p. 305). February 2, 1853: Present views as to
the construction of the ship and engines (p. 306)--Boilers (p.
307)--Advantages of oscillating engines for both screw and paddle
engines (p. 307). February 21, 1853: Proper dimensions for the Calcutta
line (p. 308)--Gas (p. 308)--Ventilation (p. 308)--Steering (p. 308).
March 14, 1853: Dimensions now determined on (p. 308). March 22, 1853:
Various dimensions settled (p. 308). April 28, 1853: Tenders are being
sought for (p. 308)--Arrangements for measuring the coal (p. 309)--Use
of clean water (p. 309). August 7, 1853: Memoranda for engines (p. 309).
November 18, 1853: Governors (p. 309)--Auxiliary engine and boiler (p.
309).
38. Extracts from Mr. Brunel’s Memoranda relating to the ‘Great Eastern’
Steam-ship (February 25 to March 10, 1854).....310
February 25, 1854: Thought and labour involved in the details of the
construction both of the ship and engines (p. 310)--Cabin arrangements
(p. 310)--Economy of material in the construction of the ship (p.
310)--A matter generally neglected in shipbuilding (p. 310)--All this
misconstruction forbidden (p. 311). March 3, 1854: Details of screw
engines (p. 311). March 10, 1854: Details of ship (p. 311).
39. Letter to the Secretary of the Eastern Steam Navigation Company, on
Position as Engineer of the Company (August 16, 1854).....311
His unusual stake in the undertaking, and the heavy responsibility he
has incurred (p. 311)--The work is one which requires that it should be
entirely under his individual management and control (p. 312)--And
therefore there must be no other adviser or source of information on any
question connected with the construction or mode of carrying out the
work (p. 312).
40. Letter to the same on an Article in a Newspaper (November 16,
1854).....313
His general rule is not to notice newspaper articles, but this one bears
the stamp of authority (p. 313)--Marked care is shown in depreciating
his former efforts in advancing steam navigation, and in representing
him, in the present case, as the passive approver of the project of
another (p. 313)--Whereas it originated solely with him, and has been
worked out by him with great thought and labour (p. 314).
41. Report to the Directors of the Eastern Steam Navigation Company,
describing the Nature of the Undertaking (February 5, 1855).....315
Labour of preparing the preliminary designs for the ship (p.
316)--[Proposed arrangements for launching]--Principal peculiarities in
the construction of the ship (p. 316)--Water-tight compartments (p.
316)--Transverse bulkheads (p. 316)--Double skin (p. 317)--Longitudinal
bulkheads (p. 318)--Economy in materials (p. 318)--Engines (p.
318)--Boilers (p. 319)--The best advice has been sought on every point
(p. 319)--The position and design of the paddlewheels (p. 319)--The
screw propeller--(p. 320)--Protection from fire (p. 320)--Masts and
sails (p. 320)--Astronomical observations (p. 320)--Lightning conductors
(p. 321)--Adjustment of compasses (p. 321).
42. Letter to G. B. Airy, Esq., Astronomer Royal (October 5,
1852).....321
As so much depends on perfect navigation, every means is to be taken to
ensure a constant determination of the ship’s position and course (p.
321)--It is proposed to have an observatory and staff of observers to be
constantly engaged in taking observations (p. 322)--What should be the
nature of these observations and of the instruments required? (p. 322).
43. Memorandum on the Management of the Great Ship (October
1855).....324
The principles to be followed in the use of this new machine, and the
qualifications of the commander, have long been a subject of anxious
consideration by him (p. 324)--This ship requires a totally different
management from that suited to ordinary vessels (p. 325)--Examples of
this proposition (p. 326)--Size of the great ship (p. 326)--By no
possibility must she be allowed to touch the ground (p. 327)--Probable
effects of the great size and mass of this vessel (p. 329)--And of her
speed (p. 330)--The proposed system of continuous observation (p.
330)--The exact course the ship is to take must be determined previously
to the voyage, and must be strictly adhered to (p. 331)--Economy of fuel
another consideration of the highest importance (p. 332)--Proper speed
of the engines (p. 332)--Use of the sails (p. 333)--Peculiarities of the
position of the commander (p. 333)--His attention must be devoted
exclusively to the general management of the system by which the ship is
to be made to go like a piece of machinery (p. 333)--His assistants (p.
334)--Four chief officers (p. 334)--A master at the head of a staff of
observers, who are to make continuous observations upon the position and
performances of the ship (p. 334)--The chief engineer (p. 335)--The
principles herein set out are to be adopted by the commander as the
guide of his conduct in working this machine (p. 335).
44. Letter on the Responsibility of his Position (sent with
last).....324
45. Letter on the Duties of the Chief Engineer of the Great Ship (March
19, 1857).....335
The success of the ship as a steamboat will depend entirely upon the
amount of power developed by the engines in proportion to the fuel
consumed (p. 336)--The peculiar duties of the chief engineer will be to
obtain the largest amount of steam from the defined expenditure of fuel,
and the use of this steam so as to obtain the largest amount of power
and the largest amount of result (p. 337)--Accurate measurements
required of fuel expended and results obtained (p. 337)--Economy in
every department may make the difference between the success and failure
of the ship (p. 337)--The chief engineer should, if possible,
superintend the erection of the engines (p. 338).
46. Extract from Report to the Directors of the Eastern Steam Navigation
Company, describing the proposed Arrangements for Launching (February 5,
1855).....341
Reasons for deciding to launch the ship sideways (p. 341)--And probably
gradually (p. 342).
47. Extract from Memorandum as to Power required to move the Ship
(September 26, 1857).....352
48. Letter to Captain Harrison on the River Tackle (September 30,
1857).....354
49. Letter to the Directors of the Eastern Steam Navigation Company on
the Nature of the Launching Operations (October 23, 1857).....355
The date is uncertain (p. 355)--The ship is to be lowered down and
floated off by a slow and laborious operation (p. 355)--She may stop or
not move at all (p. 356).
50. Memorandum on General Arrangements and intended Mode of Proceeding
in the Launching Operations (October 30, 1857).....356
51. Letter to the Directors of the Eastern Steam Navigation Company on
the State of the Operations (November 26, 1857).....366
52. Letter to the Directors, and Memorandum on the State of the
Operations (December 17, 1857).....377
53. Letter to W. Froude, Esq., describing the Floating of the ‘Great
Eastern’ (February 2, 1858).....389
54. Extract from Report to the Directors of the Bristol Dock Company on
the Condition of the Floating Harbour (August 31, 1832).....423
55. Extract from Report on the same subject (January 31, 1842).....424
56. Extract from Report on Portishead Pier (December 26, 1839).....427
57. Letter on the Distribution of Prizes, addressed to the Chairman of
the Committee of the Section of Machinery of the Exhibition of 1851
(March 11, 1850).....445
58. Extract from Report of the Jury of Class VII. of the Exhibition of
1851 on Sir Joseph Paxton’s Design for the Building.....447
59, 60, 61. Letters to Westley Richards, Esq., on the Polygonal Rifle
(October 25, 1852; February 7, 1853; November 26, 1858).....450-1
62. Extract from Letter to James Nasmyth, Esq., on the Construction of
Large Guns (April 2, 1855).....452
63. Extract from Letter to W. G. Armstrong, Esq., on the Wire Gun (June
8, 1855).....454
64. Memorandum on the Floating Gun-Carriage (December 20, 1855).....455
The principle is fixing a very heavy gun in a floating shot-proof
chamber (p. 455)--Mode of working the gun (p. 455)--Mode of manœuvring
the vessel (p. 456)--Mode of attacking the Baltic forts with a fleet of
such vessels (p. 457)--Thickness of iron required to make the vessel
shot proof (p. 458)--Best manner of constructing the vessels (p. 458).
65. Letter to the Secretary of the Admiralty on the Floating
Gun-Carriage (July 27, 1855).....459
66. Memorandum on Renkioi Hospital Buildings (March 1855).....463
Necessary conditions in designing these buildings (p. 463)--General
description of them (p. 463)--Closets and lavatories (p. 464)--External
and internal covering (p. 464)--Ventilation (p. 464)--Kitchens (p.
465)--Drainage (p. 466)--Officers’ quarters (p. 466)--Transport of
materials (p. 466)--Portable baths (p. 467)--Cost of buildings (p.
467).
67. Letter on the Direction of Railway Works (March 4, 1845).....475
68. Letter on the Position of Joint Engineer (October 16, 1843).....476
69. Letter on the Position of Consulting Engineer (December 30,
1851).....477
70. Letter on the Position of the Engineer in relation to the
Contractors (May 26, 1854).....477
71, 72, 73. Extracts from Letters on the Relations between the Engineer
and the Directors (April 15, 1850; December 6, 1851; Jan. 22,
1857).....478-481
74, 75, 76. Extracts from Letters on Interference of Directors with the
Assistant Engineers (January 19, 1842; January 28, 1842; December 12,
1851).....481-3
77. Extract from Diary (May 5, 1846).....485
78. Letter to an Inventor (September 17, 1847).....486
79. Letter on the Royal Commission on the Application of Iron to Railway
Structures (March 13, 1848).....486
80. Letter on a Proposal to obtain Recognition in England of Decorations
conferred at the Paris Exhibition of 1855 (Feb. 9, 1856).....489
81. Memorandum for Evidence before the Select Committee of the House of
Lords on the Patent Laws, A.D. 1851.....490
He has had large experience of the patent laws (p. 490)--Has never taken
out one, and is of opinion that the system is productive of immense evil
(p. 491)--Reasons for this belief (p. 491)--Conditions necessary for a
successful patent (p. 493)--Disadvantages of patents (p.
494)--Impediments in the way of improvements (p. 495).
82. Extract from Observations on the Patent Laws made by Mr. Brunel at a
Meeting of the Society of Arts (March 28, 1856).....497
83. Letter from Philæ, describing the Ascent of the Cataracts (February
12, 1859).....517
84. Report to the Directors of the Great Western Railway Company on the
Broad Gauge, &c. (August 1838).....525
He is desirous of combining his views into one report (p. 525)--The
difficulties have been overcome, or are gradually diminishing (p.
525)--And the result justifies the attempt which has been made (p.
526)--The gradients of the Great Western Railway are favourable (p.
526)--Advantages of the broad gauge (p. 527)--Reasons for adopting it
(p. 528)--Additional cost in construction is very slight (p.
529)--Weight of carriages (p. 530)--Freedom from accidents (p.
531)--Greater space for works of locomotives (p. 532)--The greater width
gives scope for improvement in every part (p. 532)--Speed obtained (p.
532)--Design of the engines (p. 533)--The continuous system of permanent
way is best adapted to high speeds (p. 535)--Calculations as to its cost
compared with that of a well constructed line with stone blocks (p.
537).
85. Report to the Directors of the Great Western Steam-Ship Company,
recommending the Adoption of the Screw Propeller in the ‘Great Britain’
Steam-ship (October 1840),.....539
This subject will be considered under two heads: 1. The efficiency of
the screw propeller, compared with the paddlewheel. 2. The advantages or
disadvantages attending its use (p. 539)--The first question involves
the consideration not merely of the effect produced, but also of the
proportionate power absorbed in producing that effect (p.
539)--Observations on the slip of the paddlewheel and screw in the
‘Great Western’ and ‘Archimedes,’ respectively (p. 540)--The result of
the comparison being, that with similar areas the screw will meet with
at least equal, if not a greater resistance, and will consequently slip
as little as or less than the ordinary paddle-board (p. 542)--Refutation
of the common error, that the action of the screw is a very oblique one,
and that it imparts a considerable rotatory motion to the water (p.
543)--Description of the action of the screw (p. 543)--The result of the
experiments is that, as compared with the ordinary paddlewheel of
sea-going steamers, the screw is, both as regards the effect produced
and the proportionate power required to obtain that effect, an efficient
propeller (p. 548)--Objections to the use of the screw propeller (p.
548)--Answered seriatim (p. 549)--Statement of the principal advantages
peculiar to the use of the screw (p. 552)--The result of these enquiries
is a strong and decided opinion in favour of the screw propeller being
adopted in the ‘Great Britain’ steam-ship (p. 557).
LIST
OF
ILLUSTRATIONS.
_ENGRAVINGS._
Portrait (engraved with permission of Messrs. Graves and Company by
T. O. Barlow, from a portrait by J. C. Horsley, R.A., in the possession
of Mrs. Brunel). ....._Frontispiece_
PLATE. ....._to face_ PAGE
I. The Clifton Suspension Bridge.....49
II. The Hungerford Suspension Bridge.....59
III. The Royal Albert Bridge at Saltash. General View......171
IV. The Newport, Windsor, and Chepstow Bridges. Elevations
and Sections.....206
V. The Royal Albert Bridge at Saltash. Elevations and Sections......218
_WOODCUTS._
FIG. .....PAGE
1. Maidenhead Bridge (longitudinal section).....174
2. Bourne Viaduct (outline elevation).....181
3. Ivybridge Viaduct (the same).....182
4. Landore Viaduct (the same).....184
FIG. PAGE
5. St. Pinnock Viaduct (outline elevation, transverse section, and
plans of piers).....187
6. Experimental Girder (transverse section).....193
7. Girder on South Wales Railway (the same).....194
8. Girder on Eastern Bengal Railway (the same).....195
9. Cumberland Basin Swing Bridge (transverse section of girder).....196
10. Windsor Bridge (transverse section of truss).....200
11. Chepstow Bridge (the same).....208
12. Saltash Bridge (the same).....219
13. Transverse Section of the ‘Great Britain’ Steam-Ship.....256
14. Copy of a Sketch in a Letter on Iron Ships.....259
15. Transverse Section of the Cradles and the Launching Ways of
the ‘Great Eastern’ Steam-Ship.....347
16. Longitudinal Section, Plan, and Midship Section of the ‘Great
Eastern’ Steam-Ship.....397
17. Monkwearmouth Dock Gates.....421
18. Bristol Dock Gate.....430
19. Plymouth Great Western Dock Gates.....435
20. Briton Ferry Dock Gate.....439
21. Brentford Dock Gate.....441
22. Renkioi Hospital.....470
LIFE
OF
ISAMBARD KINGDOM BRUNEL.
CHAPTER I.
_EARLY LIFE._
A.D. 1806--1828.
BIRTH OF MR. BRUNEL, APRIL 9, 1806--SIR MARC ISAMBARD BRUNEL--THE
BLOCK MACHINERY--MR. BRUNEL’S SCHOOL LIFE--THE THAMES
TUNNEL--SINKING OF THE ROTHERHITHE SHAFT--DESCRIPTION OF THE
SHIELD--EXTRACTS FROM SIR ISAMBARD BRUNEL’S JOURNALS FROM THE
COMMENCEMENT OF THE THAMES TUNNEL TO THE DATE OF THE SECOND
IRRUPTION OF THE RIVER, JANUARY 12, 1828--_NOTE A:_ THE BOURBON
SUSPENSION BRIDGES--_NOTE B:_ EXPERIMENTS WITH CARBONIC ACID GAS.
ISAMBARD KINGDOM BRUNEL was born on the ninth day of April, 1806, at
Portsmouth, and was the only son of Sir Marc Isambard Brunel.[1]
Most biographies commence with an account of the parentage of the person
whose life is about to be written. If this be permitted in any case, no
apology can be needed for prefixing to a Life of Mr. Brunel some
particulars of his father’s career, since he was indebted to him, not
only for the inheritance of many natural gifts, and for a professional
education such as few have been able to procure, but also for a bright
example of the cultivation of those habits of forethought and
perseverance, which alone can ensure the successful accomplishment of
great designs.
Sir Marc Isambard Brunel was a native of Hacqueville, a village in
Normandy, where his family had been settled for several generations. He
was originally intended for the priesthood; but, as he showed no
inclination for that calling, and a very decided talent for mechanical
pursuits, he was permitted to enter the French Navy; and he served in
the West Indies for six years, namely, from 1786 to 1792. On his return
home, at the expiration of his term of service, his strong Royalist
sympathies made it unsafe for him to remain in France, and with great
difficulty he managed to escape to America. He landed at New York in
September 1793, and soon obtained employment as a civil engineer. A few
years afterwards he was appointed engineer to the State of New York;
and, while holding that office, he designed a cannon foundry and other
important public works.
In January 1799, when Sir Isambard was in his thirtieth year, he came
over to England, and shortly after his arrival married Miss Sophia
Kingdom, a lady for whom he had formed an attachment some years
before.[2]
The first great work undertaken by him in this country was the machinery
for making blocks, which he designed and erected for Government at
Portsmouth.
The history of the invention and construction of this system of
machinery (for it consisted of _forty-three_ separate machines) need not
be given at length; but it may be permitted to extract the following
passage from Mr. Beamish’s ‘Life of Sir Isambard Brunel’ (pp. 97, 99,
2nd edition), in which he points out the benefits which have resulted
from its introduction, and the position its inventor is entitled to hold
among those who have contributed to the progress of mechanical science.
Where fifty men were necessary to complete the shells of blocks
previous to the erection of Brunel’s machinery, four men only are
now required, and to prepare the sheaves, six men can now do the
work which formerly demanded the labours of sixty. So that ten men,
by the aid of this machinery, can accomplish with uniformity,
celerity, and ease, what formerly required the uncertain labour of
one hundred and ten.
When we call to mind that at the time these works were executed,
mechanical engineering was only in its infancy, we are filled with
amazement at the sagacity and skill that should have so far
anticipated the progress of the age, as to leave scarcely any room,
during half a century, for the introduction of any improvement....
Beautiful as are the combinations and contrivances in the block
machinery, and highly deserving as the inventor may be of credit
for originating such labour-saving machines for the production of
ships’ blocks, there is a far higher claim to the admiration and
gratitude of all constructors of machinery, and of all workers in
metal. In this block machinery exist the types and examples of all
the modern self-acting tools, without the aid of which the various
mechanical appliances of the present day could not be produced with
the marvellous accuracy which has been attained. It is true that to
the trades unions or combinations among the artisans, is in a great
measure directly due the introduction of self-acting machines; but
the types of all these tools existed in the machines and
combinations of Brunel’s block machinery. The drilling, the
slotting, and the shaping machines, the eccentric chuck, and the
slide rest, with the worm wheel motion, are all to be found in his
machine.
On the completion of the block machinery Sir Isambard Brunel removed to
London, and took a house in Lindsay Row, Chelsea, where he remained
until he was obliged to live nearer the works of the Thames Tunnel.
Mr. Brunel’s first recollections were of the house at Chelsea; and in
1814, when he was eight years old, he commenced his school life under
the Rev. Weeden Butler, who resided in the neighbourhood. Previously to
his going to Mr. Butler, he had been taught Euclid by Sir Isambard; and
he had also a great talent for drawing, for which he had been remarkable
even from four years old. His drawings were beautifully precise and
neat, but, when the subject admitted of it, full of vigour and
picturesque effect.
After some time he was sent to Dr. Morell’s school at Hove, near
Brighton. The following extract is taken from one of his letters home in
1820:--
I have past Sallust some time, but I am sorry to say I did not read
all, as Dr. Morell wished me to get into another class. I am at
present reading Terence and Horace. I like Horace very much, but
not as much as Virgil. As to what I am about, I have been making
half a dozen boats lately, till I have worn my hands to pieces. I
have also taken a plan of Hove, which is a very amusing job. I
should be much obliged to you if you would ask papa (I hope he is
quite well and hearty), whether he would lend me his long measure.
It is a long eighty-foot tape; he will know what I mean. I will
take care of it, for I want to take a more exact plan, though this
is pretty exact, I think. I have also been drawing a little. I
intend to take a view of _all_ (about five) the principal houses in
that great town, Hove. I have already taken one or two.
In the intervals of his classical studies he seems to have employed
himself, not only in making a survey of Hove in its existing state, but
also in a critical examination of the works in progress for its
enlargement. It is told of him that one evening he predicted the fall,
before the next morning, of some houses which were building opposite the
school, and laid a bet on the subject, which his companions readily
accepted. He had noticed the bad way in which the work was done, and
that the stormy weather, which appeared to be setting in for the night,
would probably blow the walls down. In the morning he claimed the
wager, for the buildings had fallen in the night.
Except from November 1820 to August 1822, when he was at the Collége
Henri Quatre at Paris,[3] Mr. Brunel was so very little absent from home
that he became thoroughly acquainted with all his father’s undertakings.
Among these was the veneering machinery at Battersea, remarkable for the
great diameter of the saw, the steadiness of its motion, and the
mechanical arrangements for clearing the veneer from the saw; also the
works at the Government establishments at Woolwich and Chatham, and the
machinery for making shoes. They have been fully described by Mr.
Beamish; but the mere mention of their names is enough to show how great
were the advantages enjoyed by Mr. Brunel in receiving from his father
his early professional education.
From the year 1823 Mr. Brunel was regularly employed in his father’s
office. It was in the early part of this year that the project of the
Thames Tunnel first began to occupy Sir Isambard’s attention; but he was
also engaged at that time in other works of great importance, among them
the suspension bridges for the Ile de Bourbon, and designs for bridges
of the same character over the Serpentine, and over the Thames at
Kingston.[4] Some account of the Bourbon bridges, and also of
experiments with carbonic acid gas, on which Mr. Brunel was engaged,
will be found in the notes to this chapter.
The history of the Thames Tunnel will be told, as far as possible, in
Sir Isambard Brunel’s own words, as given in his journals.[5] Although
these extracts do not relate to works for which Mr. Brunel was
personally responsible, they have been inserted in the belief that they
are valuable, not only as showing the nature and extent of his duties as
his father’s assistant, but also as displaying, in the most interesting
and authentic form, Sir Isambard’s character and genius at a time when
his son was brought into hourly contact with him, and under
circumstances which would cause the influence of his example to make a
deep and lasting impression.
Previously to the year 1823 there had been several plans suggested for
the construction of a tunnel under the Thames; and it would seem that a
great demand was supposed to exist for some such means of communication
between the two sides of the river eastward of London Bridge; for after
the failure of the operations undertaken by Mr. Vasie in 1805, and Mr.
Trevethick in 1807,[6] a high level suspension bridge was proposed,
although it was not intended to be used for heavy traffic.[7]
The first reference to the Tunnel in Sir Isambard’s journals is dated
February 12, 1823. ‘Engaged on drawings connected with Tunnel;’ and on
the 17th and following days of the same month, ‘Isambard was engaged on
Tunnel.’ These entries become more and more frequent in the pages of his
diary, until it is evident that Sir Isambard’s whole time and thoughts
were absorbed in this work.
The spring of 1823 was occupied in preparing drawings and models of his
plans, and in enlisting the sympathy and assistance of various
influential persons. By the close of the year the designs were matured
sufficiently to enable the promoters of the scheme to commence the task
of organising a company for carrying it out; and in January 1824 they
resolved to call a general meeting of their friends, and invite public
subscriptions.
On February 17, Sir Isambard explained his plans at the Institution of
Civil Engineers, and on the next day a meeting was held at the City of
London Tavern, under the presidency of Mr. William Smith, M.P., more
than a hundred persons being present. Resolutions authorising the
formation of a company were passed unanimously, and the share list was
opened. In the course of an hour one-third of the subscriptions was
filled up, namely, 1250 shares; and before the end of the day the number
of shares taken was 1381.
Borings were then commenced in order to ascertain the nature of the
strata through which the Tunnel would pass. A bed of gravel was found
over the clay, which gave Sir Isambard great anxiety. A large pipe or
shaft was sunk on the side of the river, and in it the water rose to
within three feet of the surface of the ground, and fell about eighteen
inches with the tide. ‘It is manifest (Sir Isambard writes) from this
that unless the Tunnel is enclosed in the stratum of clay, it would be
unsafe to drive through the bed of gravel. The Tunnel must, therefore,
begin with the substantial clay.’
However, the result of thirty-nine borings in two parallel lines across
the river, to the depth of from 23 to 37½ feet, seemed to prove that
there was below the gravel a stratum of strong blue clay of sufficient
depth to ensure the safety of the Tunnel.[8]
A report to this effect was made to the shareholders at their first
general meeting in July, and it was also stated that the works would be
completed in three years.
The first operation connected with the works, was the constriction of a
shaft; and for this purpose land was bought on the Rotherhithe bank,
about fifty yards from the river. On March 2, 1825, the ceremony of
laying the first stone of the shaft was performed.
Mr. Smith, our chairman, attended by most of the members of the
Court of Directors, and a very numerous cortége of friends invited
on the occasion, proceeded from the Tunnel Wharf to the ground,
where they were received among the cheers of a great concourse of
people. Mr. Smith addressed the assembly in a very eloquent speech
suitable to the occasion, and performed the ceremony of laying the
first stone. From this day dates the beginning of the work.[9]
The mode in which Sir Isambard decided to construct the shaft was one
not uncommonly adopted in the construction of wells; but to apply it to
sinking a shaft fifty feet in diameter was a novel and bold undertaking.
The brickwork intended to form the lining of the shaft was built on the
surface of the ground, and the earth being excavated from within and
underneath the structure, it sank gradually down to its final position.
The brickwork was 3 feet thick, bound together by iron and timber ties,
and there were built into it 48 perpendicular iron rods, one inch in
diameter, fastened to a wooden curb at the bottom, and to another curb
at the top of the wall, by nuts and screws.
When the shaft or tower of brickwork was completed up to the top, 42
feet in height, the next step was to remove the blockings on which it
rested, and this being done the gravel was excavated and hoisted up, and
the shaft descended by its own weight.
The Rotherhithe shaft was only sunk forty feet in this manner; the
remaining twenty feet, in order to leave the opening for the Tunnel, was
constructed by under-pinning, or underlaying, as it was then termed. The
underlaying was commenced in the beginning of June.[10]
By July 4 they had got down to the level of the intended foundation of
the shaft, having passed into a stratum of gravel, black pebbles
embedded in greenish sand, with little or no water; from which
circumstance Sir Isambard was of opinion that it was unconnected with
the stratum of gravel above.
_July 12._--Engaged on a general drawing for the great shield, and
in preparing some instructions for moving the same (a very
intricate operation!)
_July 22._--Underlaying is a very laborious mode of proceeding. The
sinking of a wall well bound as the first, would evidently be the
best and cheapest mode for making another tower of 50 feet
diameter.
On the 28th Sir Isambard enters in his journal the following additional
observations upon the success of his plans for sinking the shaft:--
Considering the great labour necessary for securing the ground for
the underlaying, the waste of planking, and of shores, and the time
necessarily taken up in moving about, in securing and in baling
out the water, and the many causes of interruption, and the
imperfect way that things are done in underlaying, it is quite
conclusive that the original plan of making a shaft, by sinking the
structure, is the safest and the most economical. What is done is
sound, and when once in place, may be secured with foundations in a
very easy manner. The brickwork of the shaft is remarkably hard.
Had it been made with brick facings and rubble stone, it would
certainly be water-tight, and almost impenetrable by ordinary ways.
The _vertical ties_ and the _circular wall bands_ are not to be
dispensed with in a structure destined to be moved as the present
has been.
On August 11 the underlaying was completed, and preparations were made
for constructing a reservoir in the bottom of the shaft for receiving
the permanent pumps. This was finished on October 11, with great
difficulty, owing to the nature of the ground, which consisted of loose
sand containing a large quantity of water.
_August 19._--Engaged at home in revising my plans for the manner
of carrying on the horizontal excavation, more particularly of
penetrating through the shaft. This part of the operation requires
_indeed_ very great attention, as it presents great difficulties,
arising from the wall to be broken through, and chiefly from the
angular opening that is to be made at each extremity. Then another
consideration is the uniting the brick arches to the brickwork of
the shaft.
_September 16._--Engaged in the early part of the day on revising
my plans of future operations in the Tunnel work, and in adapting
them to the nature of the ground as it is found at the various
depths we have penetrated: namely, to about 73 feet. Went
afterwards to Maudslay to request that the great shield may be
completed.
[Sidenote: Great shield.]
_October 14._--Engaged in the early part of the morning in making
some arrangements for the working of the great shield. Too much
attention cannot be given to that subject at the early part; for,
when once in its place, it would be extremely inconvenient to make
any alteration.
[Sidenote: Preparing for the frames.]
_October 15._--The dome of the reservoir will be covered to-day
about noon; the bottom of the shaft will therefore be completed.
They are now preparing to apply two frames of the shield. The
ground now open in the front is remarkably hard; it consists of
pebbles imbedded in a chalky substance, with hard loose stones of
the nature of the Kentish rag. Everything is going on well. Devised
with Isambard how to make our wells for the descent of the
materials, &c.
Thus at last the shaft was completed, and Sir Isambard was able to
commence the Tunnel itself, which he ultimately determined to construct
in the form of a rectangular mass of brickwork, 37½ feet wide and 22
feet high, pierced by two parallel horseshoe archways, each 14 feet wide
and 17 feet high.
Before entering upon the history of this undertaking, some account must
be given of the machine which Sir Isambard Brunel devised for effecting
its accomplishment.
In order to avoid a quicksand of considerable depth and extent, the
Tunnel had to be carried but a short distance below the bed of the
river; and, as in all tunnelling through soft soil,[11] the top and
sides of the excavation had to be supported until the brickwork was
built in; and the front or face had also to be held up as the miners
advanced. This support was given by means of a machine called ‘the
shield,’ described on one occasion by Sir Isambard as ‘an ambulating
cofferdam, travelling horizontally.’[12]
The main body of the shield consisted of twelve independent structures
or ‘frames’ made of cast and wrought iron. They were each 22 feet high,
and rather more than 3 feet wide; and, when placed side by side, like
books on a shelf, against the face of the excavation, they occupied the
whole area of the face, and also the top, bottom, and sides for 9 feet
in advance of the brickwork. Each frame stood on two feet resting on
the ground, and was divided in its height into three cells by cast-iron
floors. In these cells, of which there were thus thirty-six in all, the
miners stood, and worked at the ground in front of them.
The duty which the shield had to perform was to support the ground until
the brickwork was built within the excavation; but it was essential that
this should be done in such a manner as to allow of the mining
operations being carried on; and it was also necessary that the machine
itself should be capable of being moved forward.
The first point, therefore, which has to be explained in the action of
the shield is the manner in which the earth was supported by it.
It has been already stated that each frame rested upon two feet, or
large iron plates. These two feet together covered the ground under the
frame to which they belonged, and thus the whole of the earth beneath
the frames was pressed down by the feet.
The earth above was supported by narrow iron plates, called staves, laid
on the heads of the frames parallel to the line of the Tunnel, the ends
resting on the completed brickwork behind it. The earth at the sides was
kept up by staves resting against the outermost frames.
The arrangement for holding up the earth at the face of the excavation
was necessarily of a more complicated character. Each frame supported a
series of boards called poling-boards, by means of small screw-jacks or
poling-screws, two to each poling-board, which abutted against the
frames, and pressed the boards against the earth. The boards were 3 feet
long, 6 inches wide, and 3 inches thick, and were arranged horizontally.
These poling-boards, more than five hundred in number, covered the whole
surface in front of the frames.
To resist the backward thrust of the poling-screws against the frames,
each frame was held forward by two large screws, one at the top of the
frame, and the other at the bottom, abutting against the brickwork of
the Tunnel. The brickwork was completed close up behind the shield as it
advanced.
The way in which the earth was excavated, and the shield moved forward,
has now to be explained.
The plates or staves which supported the ground at the top and sides of
the shield were pushed forward separately by screw-jacks; but in order
to advance the poling-boards in front, it was necessary that that
portion of the ground against which they pressed should be removed.
The miner, standing in his cell, took down one, or, at the most, two of
the poling-boards, commencing at the top of the cell, and having
excavated the earth a few inches in advance, replaced the poling-boards
against the newly-formed face, pressing them against it with the
poling-screws. Thus the excavation was carried on without depriving the
ground of the support it received from the shield, except at the point
where the miner was actually at work.
The operation of advancing the frames was effected in the following way.
When everything was ready for a move, one of the feet which carried the
frames on jointed legs was lifted up, and advanced forward a few inches,
and then pressed down on to the ground, until in its new position it
again bore the weight of the frame. This done, the other foot was
lifted, moved forward, and screwed down in the same manner, and then the
frame itself was pushed ahead by means of the large abutting screws,
which kept it top and bottom from being forced back on the brickwork.
It is, however, evident that these abutting screws would have been
unable to push on the frame, while the ground in front was pressing back
the poling-boards against it; therefore, during the process of moving a
frame, it had to be relieved from the thrust of its poling-screws.
Accordingly, when it was desired to advance any one of the frames, the
butts of the poling-screws of the tier of boards in front of it were
shifted sideways, so as to rest, not against the frame to which they
belonged, but against the frames next it on either side. This done, the
frame itself was advanced, and was then ready to receive again its own
poling-screws, and also those belonging to the adjoining frames, so that
they might in their turn be moved forward. It will thus be seen that the
whole shield was not moved forward at one time, but that the frames were
advanced alternately.
There were many other ingenious arrangements in the design of the
shield, which need not be referred to in a description intended only to
give such a general idea of the machine as may make the history of its
operation intelligible.[13]
When the frames had been completed in Messrs. Maudslay’s factory, they
were conveyed to Rotherhithe, and lowered down the shaft. An opening had
been left at the bottom of the wall, about 37 feet wide by 22 feet high,
and against this the shield was erected. It was then ready to commence
its progress through the ground below the river.
On November 25, 1825, the shield made its first start. Sir Isambard was
unfortunately unable to witness what was in fact the actual commencement
of the Tunnel, as he had three days before been seized with a sudden and
alarming attack of illness, which kept him at home till December 6. The
works were left under the direction of Mr. Brunel.
_December 8._--The great shield is advancing very slowly, meeting
with much interruption by the water, which still runs within the
cells, and also by the difficulty of forming abutments for the
frames. [_Temporary abutments were necessary until the shield was
sufficiently advanced to allow of its being pushed forwards from
the brickwork built up behind it._]
_December 29._--The frames are very much out of level in the
transverse line of the Tunnel. This would be attended with serious
inconvenience if I had not provided for the means of recovering any
irregularity that might take place, and which, as it appears,
cannot perhaps be prevented; but having foreseen this, I have
provided the remedy by being able to take down the top of each
frame, and to remove the top staves in parts, or the whole, at
pleasure--a very important provision it proves to be.
_January 16, 1826._--Too much precaution cannot be taken, in the
management of the frames, to have the leg-screw particularly well
secured, as every foot-run of the arch of the Tunnel sustains 82
tons. Each frame carries as follows:--
The two end frames each 65 tons = 130
Ten others, each 52½ " = 525
---
655 tons.
_January 21._--The ground at the top and sides very good; same in
the front. In breaking the ground out of the limits of the shield
on the right a great deal of ground fell in. This indicates that,
if it was not for the protection of the shield, nothing could be
done. This accounts also for the occasional breaking of the ground
in making the drift in 1809.
[Sidenote: Tunnel begun.]
The brickwork of the entrance being carried as far as directed, the
body of the Tunnel was begun to-day.
[Sidenote: Water broke into the works.]
_January 26._--Isambard went down to Rotherhithe; the water had
broken in in great abundance upon the work over Nos. 4 and 5. [_The
twelve frames were distinguished by numbers._] A 4-inch pipe was
driven over the shield from inside the shaft, but the water did not
follow it, and the stream augmented very rapidly. The frame No. 5
was moved forward, and it checked the water for a moment, but it
came again with violence. A heading was immediately ordered by
Armstrong [_the resident engineer_] from the east well, in which
Isambard concurred.
_February 3_.--Ordered a pit to be opened and made by sinking a curb 8
feet diameter and 18 inches thick, well bound with bolts. [_This pit was
a well sunk from the surface to enable the gravel containing water, into
which the head of the shield had penetrated, to be removed, and clay
substituted_.]
_February 6_.--The shaft begun last night, and was sunk 20 feet to-day,
and remarkably true. Had we known the ground as we now know it, we
might, by having opened a well contiguous to the great shaft, have sunk
the shaft in a week; but for that purpose we must have had two steam
engines, one for pumping the water, and the other for taking up the
ground.
[Sidenote: Unremitted attention wanted.]
_February 10_.--Went very early to the Tunnel for the purpose of giving
directions to prop up the back of the staves, which, for want of weight
at the new shaft, might be overbalanced by the pressure of the ground at
the back. I could not rest a moment until it was done, for the
consequences might have been fatal, at this moment in particular. What
incessant attention and anxiety! To be at the mercy of ignorance and
carelessness! No work like this.
[Sidenote: Observations on the mode adopted to check the water.]
_February 12_.--The ground having been opened carefully from under the
curb of the pit [_see above on date February 3_], the greater part of
the gravel was removed, and stiff clay substituted for it. This was done
by driving first some wrought-iron flat bars, which kept the ground up.
This shows that the shield is a most powerful protection, and would
enable us to penetrate through a bed of gravel. Though the breaking in
of the water had somewhat terrified the man in No. 5, he soon returned
to his post, and the others have acknowledged their full confidence in
the security afforded by the shield. The boring ahead had not yet been
attended to: it is owing to the want of this precaution that this
accident is chiefly to be ascribed; for had we known as much as we now
do, we might have passed through without the pit being opened.
_March 1_.--Water at the back of the frames, but less than before. The
men show a great deal of spirit in overcoming the present difficulties.
Isambard was very busy yesterday and to-day in the frames, and about the
works. He was severely hurt in the leg by a piece of timber falling
against it. [_This accident prevented his attending again at the Tunnel
until the 24th_.]
On March 6 the proprietors paid a visit to the Tunnel, and were highly
satisfied with what they saw. On that evening Sir Isambard writes:--
It is of absolute necessity _now_ to provide for everything that is
conducive to the more expeditious management of the frames, and to
a greater facility in getting up the brickwork. If these two points
are realized, then indeed we may soon expect to be moving at a good
rate--not less than I have held out, namely, 3 feet per 24 hours.
[Sidenote: Water stopped as expected.]
_March 11._--Received early in the morning a report from Armstrong
stating that the water was completely stopped--that it had been
stopped during the night. Aware that we had passed the gravel, it
was of course expected that we were under the clay; means were
therefore resorted to, to drive clay and oakum at the tail of the
top staves, which was productive of a very good effect. The great
shield was soon entirely free of water. This shows the efficiency
of the shield to oppose difficulties which could not have been
overcome without the complete protection it affords, under almost
any circumstances. Indeed this has been a tedious operation since
January 25, when the water first burst upon No. 5, at the front of
the shield. The miners as well as the bricklayers have worked with
great spirit and perseverance through the whole, during a period of
44 days. The well that was made at the front of the shaft has been
of use in acquainting us with the extent of the open ground we had
to pass through. It will be made a useful opening for ventilating
the works. By means of this well we have been able to apply the
lead pipes with which the water has been diverted: it is not
therefore a useless expense. Things were put in better order to
prepare for a more expeditious way of working. Directions were
given to place the frames in a better condition. Isambard is still
too unwell to go to the Tunnel.
[Sidenote: Considerable slip of ground: how to check it.]
[Sidenote: Very dangerous.]
_March 25._--Went to the Tunnel with Isambard. Found that a
considerable fall of ground had taken place again at the right
side. No one could account satisfactorily for it. I inspected it,
and directed that, after making it good, flat bars of iron be
driven at the head of the side staves, in order to pin it up, and
in order to enable the miners to get at the solid ground. It is
very bad and extremely dangerous; the ground is evidently the same
as that which, in the report of the first attempt, was found so
loose as to have dropped upon the works, leaving a large cavity
above, when it is said the man ascended and made good the hole. We
should be warned by this, lest we should meet another as fatal as
it ultimately was on that occasion. [_This observation refers to
the driftway of 1807._]
_April 24._--By Armstrong’s report the water is entirely out, and
the men at work in the morning in removing the dirt, &c. Isambard
engaged at the Tunnel, where I am not yet able to attend as often
as I could wish. Everything goes on well, much through his
exertions.
_May 11._--One hundred feet will be completed to-night.
_May 22._--The top plate over the frame No. 1 has been cracked
without any particular violence or stress. It appears that it is
nothing but the change of temperature that is the cause of that
rupture. The accident justifies the opinion I have of cast-iron not
being safe upon traction, and the precaution of having had
wrought-iron bolts at the back of the frames. [_These were vertical
rods which took the tensional strain._] Without these bolts what
would have become of the shield, if one casting was to break? The
fracture was accompanied with a loud report like that of a gun.
Isambard was in the works at the time of breaking: nothing could
have prevented it.
[Sidenote: The shield being too much out, resolved to move it
bodily.]
_May 25._--I observed that nothing whatever had been gained to
recover the deviation [_the shield had gradually worked 2 feet 3
inches to the westward_], which subjects us to so much
inconvenience and loss of time. The only way to bring the shield
right is by taking the frames sideways.
_June 3._--Finding it too laborious and almost fruitless to bring
the frames in the right way, I came to the determination of having
them brought bodily to the east by cutting the ground on the side.
I accordingly gave directions to Armstrong to proceed in making a
heading out of No. 12, and by securing the side staves to continue
downwards until the ground be clear. The working was accordingly
discontinued in front.
_June 4._--The mode of proceeding by the common way of mining shows
the impracticability of carrying a large excavation anywhere,
particularly under a considerable body of water. The expense of
timbering would be too great, even if it could be sound. The ground
above the frames is remarkably good, but under it there is a
stratum of silt which breaks and falls in large masses.
[Sidenote: Isambard’s service very important and most efficient.]
_June 5._--Isambard got into the drift, and gave the line for the
better disposition of the staves, which was afterwards done in a
proper manner. Isambard’s vigilance and constant attendance were of
great benefit. He is in every respect a most useful coadjutor in
this undertaking.
_June 10._--The last frame (No. 1) is brought close to the others,
and the brickwork brought up to fill the back.
[Sidenote: Dangerous state of the ground. Precautions taken.]
_June 15._--On inspecting the face of the ground this morning I
observed a breach in the front of Nos. 3, 4, and 5, where the
ground has given way in the lower cell. This was truly alarming. I
ordered iron staves to each floor in order to pin the ground, and
thereby to counteract the slipping which would immediately take
place.
_June 19._--The bricklayers left off work, but, on enquiring into
the cause, I learned there was no other but to have a libation upon
the new arrangement of piece-work.
_June 29._--Gave positive directions to cut only 4½ to 5 inches
thick at a time at the front of the top cells, instead of 9 inches,
as they had done for some time.
_July 3._--The great question is, does the clay undulate at its
surface? We should have some reason to apprehend that it does so,
because at the beginning we had not proceeded many feet into the
clay when we struck again into the gravelly stratum. The surface of
the clay must therefore have sunk at that particular spot; which
circumstance seems to warn one of the need of great vigilance and
great prudence in the progress of the enterprise.
[Sidenote: Cofferdam burst at Woolwich.]
[Sidenote: Warning for us.]
_July 10._--A cofferdam burst yesterday at the works at Woolwich,
having blown up from the foundation. How cautious this should make
our men! The cofferdam may be repaired, and very easily too, but an
irruption into the Tunnel--what a difference, particularly at this
early period!
[Sidenote: Carelessness of the miners.]
_August 10._--Found the lowest cell of No. 1 left by the workmen
_without a single poling against the ground_. This is indeed a most
unjustifiable neglect.
_August 12._--At six this morning completed 205 feet.
[Sidenote: Observations on the bad effect and consequence of
driving on as is done.]
_August 21._--This piece-work has not been productive of much
effect as to quantity of work. As to quality it is very
questionable. A work of this nature should not be hurried in this
manner. Fewer hands, enough to produce 9 feet per week, would be
far better than the mode now pursued _from necessity_, but not from
inclination on my part. Great risks are in our way, and we increase
them by the manner the excavation is carried on. The frames are in
a very bad condition.
_September 5._--It is much to be regretted that such a work as the
Tunnel should be carried on by the piece. Obliged to drive on, no
time is left to make any repair, or to recover any lost advantage.
Isambard is most active. Mr. Beamish shows much judgment in his
exertions, and zeal in his attendance.[14]
[Sidenote: Water breaking in at back of frames.]
[Sidenote: How to check it. Isambard’s exertions.]
_September 8._--About 2 P.M. I was informed by Munday that water
was running down over No. 9. I went immediately to it. The ground
being open, and consequently unsupported, it soon became soft, and
settled on the back of the staves, moving down in a stream of
diluted silt, which is the most dangerous substance we have to
contend with. Some oakum was forced through the joints of the
staves, and the water was partly checked. Isambard was the whole
night, till three, in the frames. At three I relieved him. He went
to rest for about a couple of hours; I took some rest on the stage.
[Sidenote: Things improving.]
_September 9._--Towards noon the stream changed its character. The
clay, being loosened by the water, began to run, but it thickened
gradually. It was late in the evening before the loosened clay
acquired the consistency of a loose puddling, which covered the
staves, and made them a complete shield against further irruption,
or rather, oozings of mud. If we consider that at this place we
have at the utmost 9 feet between the top staves and the gravel,
over which the river flows, it is most satisfactory and most
encouraging to have this additional proof of the protection which
the shield affords. At nine o’clock at night Isambard sent me word
that ‘tout va à merveille;’ indeed it was so, for it was like a
stopper interposed between the river and the top-staves. Instructed
as the men were by the first accident, they went on as usual in the
irrespective occupations. Pascoe, junr., and Collins were
remarkably active and persevering, and some other men equally so;
while old Greenwell encouraged them by a speech of his own in high
commendation of the security of their situation.
[Sidenote: Water more abundant. Is it from the river?]
_September 12._--The water, bringing with it a sort of clay broken
in small particles, increased to an alarming degree. In consequence
of this continued displacement of the silt and clay, a cavity had
been formed above the staves. At about three, when I had gone to
the Court of Directors, the ground fell upon the staves with great
violence, causing a surge most alarming as to probable
consequences. Isambard was at that moment in the upper frames, and
he gave directions for increasing the means of security. On my
return I found things much worse than I left them, but every means
of security was judiciously applied. During the night in
particular things presented a very unfavourable appearance. The
men, however, were as calm as if there were no other danger to be
dreaded than wet clothes or the splashing of mud. I observed the
men in the lower cells were _sound asleep_.
[Sidenote: Exertions by the men.]
[Sidenote: Slight improvement.]
_September 13._--Every means were resorted to in the course of the
night and during the early part of the day to stop the water. The
men have shown great zeal and good management in their respective
avocations, and above all the utmost confidence. Isambard has not
quitted the frames but to lay down now and then on the stage. I
have prevailed on him to go to his bed, or rather, used my
endeavours to induce him; but he has not since last Friday night
(the 8th). Things were rather better at the close of the day.
_September 14._--Things upon the whole have assumed a more
favourable aspect. The situation is nevertheless very critical.
Nothing but the utmost precaution in following up what has begun
can bring us out of it. This has been a most eventful week!
_September 18._--Isambard was the greater part of the night in the
works, and the benefit of his exertions is indeed most highly felt:
no one has stood out like him! Everything is quite safe, the water
is kept back, and the work proceeds in a most satisfactory manner.
_October 22._--It is evident [_from a flow of silt which had taken
place on that day_] that with the shield we have passed close under
a body of collected water a few inches only above the staves.
Isambard is too unwell to stay long in the works.
[Sidenote: The want of a drain subjects us to much inconvenience.]
_October 24._--The want of the main drain which was originally
intended to carry the water to the main reservoir is felt
everywhere. This drain is in my original plan, but the committee
expressing on several occasions a wish that I should dispense with
it, I complied, most reluctantly however, to prove my earnest wish
to reduce the expenses. It will not, I apprehend, be found an
economy.
[Sidenote: Effect of the shoes in keeping the ground dense.]
_October 26._--Every step we take shows how much security is
derived from the shoes, supporting as they do the shield and the
superincumbent weight. They press down in the same proportion the
ground on which they bear. They keep it as dense as it originally
was, and fit it for the structure that is to come upon it. It is
evident, therefore, that what is wanted is that the ground should
be kept pressed. It is with this object in view that I have
holdfasts and jacks. What incessant vigilance is required, what an
incessant call on the resources of the mind, not only to direct,
but more particularly to provide for many things that may occur.
_November 17._--At this date 307 feet 9 inches had been
completed.[15]
_December 8._--The evil [_that of not having a proper drain_] is
going on with us, and without any remedy except the drain, or a
cesspool by way of expedient. How much anxiety must one feel at
being so circumstanced! Should any water break in, how should we
proceed? This is another source of great solicitude. We have no
command of the frames when they rest upon wooden legs, or when the
screws are bent; and what is worse is that the men drive on without
any consideration or any fear of consequences. This circumstance,
and the apprehension of the water breaking in, are matters of the
most dreadful anxiety.
[Sidenote: Superincumbent weight varying daily, and still more
every fortnight. What stress on the frames. The shoes have never
yielded; a most important circumstance.]
_December 12._--Little do others know of the anxiety and fatigue I
have to undergo day and night. Advanced as we are, we have only
gained somewhat more experience, but the casualties are just the
same. An accident now might be as fatal as it would have been 200
feet back, or as it would be 200 feet forwards. We have not a
period when we can think ourselves safe except when we have
connected these arches with a shaft on the other side. Loaded as we
are with the weight of the river, we have to advance our shield and
build our structure under that weight, a weight which varies twice
a day, and twice a month to a much greater extent. _The shoes are
the great foundation of our security._ When once pressed down with
the greatest power that can be applied, they do not give in the
least afterwards. They have not yielded even upon loose gravel; we
must therefore congratulate ourselves that they have answered so
completely. We have now walked our frames upwards of 350 feet; we
have had to renew the legs and the heads, but it is not through
want of strength so much as from mismanagement. The first legs were
never injured so long as their action was limited to 3 inches, but
when it was increased to 6 inches, they immediately gave way one
after another, without however any damage to the structure or to
the shield. The heads gave way, or began to give way, from the
moment the legs did; because, when a leg gave way, it brought upon
the contiguous frame an increased weight which broke the heads one
after another. That the breaking of so important a part of our
shield should not have been attended with any bad consequences is a
proof that provision had been made for the casualty. The proof that
it had been foreseen and provided for is in the manner these heads
were adapted to the frames. By the way they were fixed they would
be easily taken down and replaced. Though the heads gave way, the
top staves were not materially affected by it, and the service
continued until new heads were substituted. Some have fancied that
the ground did not bear wholly upon the shield and the arches, but
supported itself in parts. Experience proves that the pressure is
rather more than that which rests artificially on the frames. The
ground is compressed all round by the increased weight of high
water: we might therefore conclude that the shield operates as a
pillar, that supports beyond the limits of its base or cap. It is a
great satisfaction to be able to say that so long as we followed
the original plan, nothing gave way except the back screws. These
again were damaged by being run out of the sockets. We may
therefore ascribe most of the evils and damages to the increased
range of action, and still more to the rude implements the men have
used, whenever they met with any difficulty in moving the frames.
If it is considered that we had no other men to train in the use of
this immense machine but excavators and miners, very great
allowance must be made for what has occurred.
[Sidenote: Falling of three facings from neglect. Awful!]
_December 20._--An accident of an alarming nature occurred. The
poling-screws of Nos. 10 and 12, being on No. 11, Moul, the miner
in that frame, removed his butting screw; the consequence was that
the frame started back, the polings and poling-screws fell down
with a tremendous crash, and the ground followed to a considerable
extent. This is the most formidable accident that has yet occurred
in the face of the work. The ground was fortunately unusually firm,
and no fatal consequences ensued.
_December 31._--Isambard and nine friends sat down to a dinner
_under the Thames!_ Now a year is over since we began to make any
progress horizontally, for we had only 11 feet of arch when the
water broke in on January 24 last. We may therefore say that the
whole of what has been made of the Tunnel has been made in that
period. It is worthy of remark that until the end of April no
fracture whatever, no bending of the legs, had taken place,
notwithstanding that we had supported for a period of nearly three
months a greater weight than we ever had since. The ground nearly
40 feet high _kept sinking upon us_ as we advanced, and yet no
stave, no top, no leg gave way. Each leg was capable of carrying
nearly 80 tons at the point of fracture, consequently the aggregate
strength of 36 legs was equal to 2,880 tons, which is six times
over the greatest effort that could be exerted by the
superincumbent weight. The heads, after they had given way,
remained in place, some--namely, Nos. 1, 8, 12--for seven months,
and the others from four to six months. It cannot be said therefore
that there was a want of strength, since the broken heads continued
to perform for so many months after being so much damaged; nor is
there any defect in the iron. If the frames were, as some have
fancied, lanky, which implies weakness in their sides, how could
they have supported the alternate stress to which they are put by
standing alternately on one leg? Not one single joint has yet
started. Every frame has been upwards of 2,000 times in that raking
posture, consequently the shield has been upwards of 24,000 times
strained under the weight that has broken the heads. One single
side has broken, and is now as good as the rest. Is such a machine
to be stigmatised as it has been, without looking more minutely
into its operations?
[Sidenote: Observations on the responsibility attached to this
enterprise.]
_January 4, 1827._[16]--A work that requires such close attention,
so much ingenuity, and carried on day and night by the rudest hands
possible--what anxiety, what fatigue, both of mind and body! Every
morning I say, Another day of danger over!
_January 12._--It is astonishing how the silt resists the sliding
of the top staves. Assured as we were of having stiff clay from 33
to 37 feet, with what confidence we might have looked to making 18
feet per week. There would be no difficulty in having accomplished
it. We must not look back, but overcome all difficulties!
[Sidenote: Isambard on duty several successive nights.]
_January 16._--Isambard having been up several successive nights,
went to bed at ten, and slept till six the next morning. I am very
much concerned at his being so unmindful of his health. He may pay
dear for it.
_February 2._--Work done to this day 405 feet 4 inches.
_February 3._--I visited the works; and, being in the cabin, I
complained of the dust there. _Dust under the Thames!_
_February 26._--I went to the Tunnel. The arch being well lighted
up, and the whole walk completed, a few visitors were admitted. The
coup d’œil was splendid. Mrs. Brunel, Emma, Sophia and her three
little children were the first. It gave me great pleasure to see
the whole of my family in the new scene.
_March 21_.--There being no clay above us, there is much to
apprehend from the springs. It would be much better to work slower
than we do. It is indeed very hard to be under the necessity of
driving. Anxiety increasing daily.
[Sidenote: No clay above head; should work slower.]
[Sidenote: Water increasing daily.]
_March 28_.--The top pumps failed; the water rose above the
abutting screws. The frames of some of them could not be advanced,
nor could the bottom brickwork be laid down--great source of
complaint. Isambard called the men in at 10 o’clock; they went on
cheerfully. It is surprising that the men are so steady.
[Sidenote: Out situation is getting much worse daily.]
_March 29_.--Things are getting worse every day by the influx of
water; by which the ground is softened, and the operation rendered
extremely complicated and slow. As to the ground, it is evident we
are now as Isambard found it by his borings of August last. We have
nothing above our heads but clayey silt, and it is of a nature to
be detached and run into mud by the action of water.
_April 3_.--The pumping now requires forty hands. There is no
exaggeration in saying that the influx of water, and the badness of
the ground, cause an extra expense of 150_l_. a week.
[Sidenote: Obstacles in every way.]
_April 7_.--It may now be said that we are contending with the
elements above and around, gaining and disputing every inch that we
add to the structure.
_April 9_.--Isambard’s birthday, he being of age to-day.
_April 14_.--Doing as well as can be expected from the nature of
the ground, and the difficulties that increase upon us.
[Sidenote: To be obliged to drive too fast is a sad alternative.]
_April 18_.--The faces are found extremely tender; but having
proceeded with great caution, no accident occurred. None, I feel
confident, would occur if all idea of piece-work were abandoned. It
always operates as a stimulant, a very dangerous one. Obliged to
drive on, on account of expense, we run imminent risks indeed for
it. That a work of this nature, under such circumstances, should be
thus carried on, is truly lamentable. It is obvious that the clay
we have above our heads has been broken, by the ground beneath it
running or breaking in upon us. We shall have to fight it out until
we have a stronger or thicker stratum of clay. Sad prospect indeed
it is for us!
_April 20_.--The ground at No. 1 broke in again, and occasioned
great delay. Some bones and china came down.
_April 22_.--The diving-bell being on the spot, and Isambard having
moored it over the shield, he and Gravatt[17] descended at thirty
feet water. They found the same substances which had come through
the ground into the Tunnel. When Isambard was in the bell, he drove
a strong rod into the ground. Nelson, who was in the frame, heard
the blows.
[Sidenote: A dreadful panic.]
_April 29_.--Ground improving as we advance; we are not, however,
free from danger: a dreadful alarm took place this morning. While
Isambard and Gravatt were at breakfast, the porter came running in,
and exclaiming, ‘It is all over! The Tunnel has fallen in, and one
man only has escaped.’ Gravatt was the first to get to the spot,
and found all the pumpers upon the floor of the shaft, all
stupefied with horror, though every one was there quite safe, and
no rush of water was heard. Gravatt and Isambard were soon in the
shield, where they observed that a small portion of clay had fallen
from the top on the top floor.
_May 8_.--At half-past three in the morning, an irruption took
place, bringing down the deposits of the bottom of the river--lumps
of clay, stones, bones, wood, nails, &c., &c., with water. The
pumpers and men on the stage (Irish) all ran away, some exclaiming,
‘The Thames is in! The Thames is in!’ Ball and Rogers stood to
their post, and soon stopped this most formidable attack.
_May 10_.--Great difficulties present themselves, that oppose our
progress; the chief, however, is the lodgment of water above our
heads. There it loosens the silt or sand, and runs out, leaving
cavities that cause the clay above to break, and run down in lumps
and disturbed streams. This is very awful! This opens the way for
the river.
[Sidenote: Consequences of want of care more terrific and
mischievous than any preceding ones.]
_May 12_.--In moving No. 6, they left by some unaccountable neglect
the top staves behind, and in that state two top polings were taken
down. The ground being very bad, and high water at the same moment,
the ground began swelling. Attention was called to several points,
and Gravatt continued in No. 6. He drew out at the front of the top
staves a shovel, and also a hammer, that had come through the
ground above. They are the same which Isambard left at the bottom
of the river, when he went down in the diving-bell.
[Sidenote: Triumph of the shield.]
_May 13_.--Notwithstanding every prudence on our part, a disaster
may still occur. _May it not be when the arch is full of visitors!_
It is too awful to think of it. I have done my part by recommending
to the directors to shut the Tunnel. My solicitude is not lessened
for that: I have indeed no rest, and I may say have had none for
many weeks. So far the shield has triumphed over immense obstacles,
_and it will carry the Tunnel through_. During the preceding night
the whole of the ground over our heads must have been in movement,
and that too at high water. The shield must have therefore
supported upwards of _six hundred tons_: it has walked for many
weeks with that weight twice a day over its head. What flippancy
and inconsistency in some individuals, who, without any knowledge
of the subject, without so much as examining the state of the work,
will without the least reflection and hesitation obtrude their
suggestions upon every case. What shallow conceit for such to
pretend they can know better than those that have already the
experience that must result from years of deep thought, from days
and nights of incessant attention; who have the advantage of the
combined talents of several ingenious men, who devote their
undivided study, the whole resource of their well-stored minds, to
the enterprise; and to add to this, the benefit of the skill of one
hundred miners and excavators. Among this class of men, some have
been employed in the most perilous enterprises, when each
individual must have acted upon his sole judgment, where, in fact,
there is no room for an engineer to instruct and direct their
efforts. How easy it is to attack everything, to detract from the
merits of the best plan. There is always some weak point which may
be open to the penetration of the shallowest mind. Then comes the
exulting expression, _That I always said would never do, &c.,_ and
all the consequences with it.
[Sidenote: How easy to detract.]
_May 15_.--The water increased very much at 9 o’clock. This is
_inquiétant_! My apprehensions are not groundless. I apprehend
nothing, however, as to the safety of the men, but first the
visitors, and next a total invasion by the river. We must be
prepared for the worst. I have had no rest for many weeks on this
apprehension. Should it occur we must make the best of it, by
improving our situation.
_May 17_.--There is no doubt of the ground having improved very
materially since last Saturday. Very cheering indeed.
_May 18_.--Visited by Lady Raffles and a numerous party. Having had
an intimation by Mr. Beamish of their intended visit, I waited to
receive and to accompany them, not only from the interest I felt at
being acquainted with Lady Raffles, but also from motives of
solicitude, knowing that she intended to visit the frames. Indeed,
my apprehensions were increasing daily. I had given some
instructions for enquiring where we could obtain clay, that we
should have some barges full of clay to be in readiness. I was most
anxiously waiting for the removal of the tier of colliers that was
over us, being convinced that we should detect some derangement
then. I attended Lady Raffles and party to the frames, most uneasy
all the while, as if I had a presentiment, not so much of the
approaching catastrophe to the extent it has occurred, but of what
might result from the misbehaviour of some of the men, as was the
case when the Irish labourers ran away from the pumps and the
stage. I left the works at half-past five, leaving everything
comparatively well: Mr. Beamish continued on duty.[18]
Mr. Gravatt’s account is as follows: I was above with I. Brunel
looking over some prints, Beamish being on duty. Some men came
running up and said to Isambard something I did not hear. He
immediately ran towards the works, and down the men’s staircase. I
ran towards it, but could not get down. I leaped over the fence,
and rushed down the visitors’ stairs, and met the men coming up,
and a lady, who I think was fainting. Met Flyn on the
landing-place, who said it was all over. I pushed on, calling him a
coward, and got down as far as the visitors’ barrier. Saw Mr
Beamish pulled from it. He came on towards the shaft walking. I
went up to him to ask him what was the matter. He said it was no
use resisting. The miners were all upon the staircase; Brunel and I
called to them to come back. Lane[19] was upon the stairs, and he
said it was of no use to call the men back. We stayed some time
below on the stairs, looking where the water was coming in most
magnificently. We could still see the farthest light in the west
arch. The water came upon us so slowly that I walked backwards
speaking to Brunel several times. Presently I saw the water pouring
in from the east to the west arch through the cross arches. I then
ran and got up the stairs with Brunel and Beamish, who were then
five or six steps up. It was then we heard a tremendous burst. The
cabin had burst, and all the lights went out at once. There was a
noise at the staircase, and presently the water carried away the
lower flight of stairs. Brunel looked towards the men, who were
lining the staircase and galleries of the shaft, gazing at the
spectacle, and said, ‘Carry on, carry on, as fast as you can!’ Upon
which they ascended pretty fast. I went up to the top and saw the
shaft filling. I looked about and saw a man in the water like a
rat. He got hold of a bar, but I afterwards saw he was quite spent.
I was looking about how to get down, when I saw Brunel descending
by a rope to his assistance. I got hold of one of the iron ties,
and slid down into the water hand over hand with a small rope, and
tried to make it fast round his middle, whilst Brunel was doing the
same. Having done it he called out, ‘Haul up.’ The man was hauled
up. I swam about to see where to land. The shaft was full of casks.
Brunel had been swimming too.
The first alarm, as I heard it, was as follows: Goodwin, in No. 11,
said to Roger, in the next box, ‘Roger, come, help me.’ Roger said,
‘I can’t, I have my second poling down, and my face will run in.’
In a little time Goodwin said, ‘You must come,’ which Mr. Beamish
directed him to do. Roger turned round and saw Goodwin through a
sheet of water. Corps, a bricklayer, went to help Goodwin: he was
knocked down. Roger made his way alone, calling to Mr. Beamish,
‘Come away, sir, ‘tis no use to stay.’ Roger saw Corps fairly
washed out of his box like a lump of clay.
Sir Isambard’s journal continues:--
_May 19._--Relieved as I have found myself, though by a terrible
catastrophe, of the worst state of anxiety, that which I have been
in for several weeks past, I had a most comfortable night. Isambard
and Gravatt descended with the diving-bell, and stood upon the
tails of Nos. 10, 11, and 12.
_May 20._--Having descended into the hole and probed the ground, I
felt that the staves were in their places, and that the brickwork
was quite sound. It is evident that the great hole has been a
dredging spot. A large mass of bags full of clay, and united
together with ropes, was let down. The Rotherhithe curate, in his
sermon to-day, adverting to the accident, said it was a fatal
accident, that it was but a just judgment upon the presumptuous
aspirations of mortal men, &c.! The poor man!
_May 23._--Went with the diving-bell to examine the ground and the
bags, which do apparently well, but it is working rather in the
dark. It cannot, however, fail of making a much better stratum than
that we had before. The plan is therefore good.
On the 30th a raft was sunk over the shield, and the water in the shaft
was brought so low that the last flight of steps was visible. However,
on the next day the river broke in again; and as it was found that the
raft was open at the west side, it was raised and towed on shore.
_June 5._--There is much danger in getting out of the diving-bell,
the bags are so loose in some places. One might sink and be
swallowed, which had very nearly happened to-day. Isambard and
Pinckney being down, the latter lost his hold. The footboard being
accidentally carried away, he could not have recovered himself had
not Isambard stretched out his leg to his assistance.
_June 17._--Visited by Charles Bonaparte. Isambard took him into
the arch with the yawl. Isambard fell overboard.[20]
On June 19, a general meeting of the proprietors was held, to consider
the position of the company. Sir Isambard addressed the meeting, and
also presented a long report, in which he entered very fully into the
circumstances of the recent accident and the causes which led to it. He
then described the means he had taken to restore the works by sinking
bags of clay and gravel. He adds: ‘I have already succeeded in closing
the hole through which the water first penetrated, and feel confident
that the second opening which afterwards appeared is also stopped, but a
short time is necessary to elapse for the new ground over the shield to
settle and consolidate. It has already supported a head of water of
thirty-five feet.’
_June 25._--At 7 P.M. made preparations to re-enter the shield.
Isambard, mustering the men who had been the last to quit the
frames, told them they would be the first to take possession of
them again--a precedence due, as he said, to them. Rogers, Ball,
Goodwin, Corps, and Compton, were accordingly ordered to trim
themselves for the expedition, provided with a phosphorus box, and
dressed in light clothes, to be fit for a swim.
At about ten o’clock, Isambard and Mr. Beamish, accompanied by Ball
and Woodward (miners), went down with the punt, and got to the
large stage, the head of the crane just emerging. It was found
impossible to get into the frames, as a mound of clay and silt
closed the entrance. The centering was in place and quite sound,
and of course the brickwork. Finding that they could not get
nearer, they gave three cheers, which were rapturously answered by
the men at the mouth of the Tunnel. Having placed candles upon the
ground that closed the entrance, and upon the head of the crane,
they returned. Isambard, having promised that the men who had left
the frames last should be the first to re-enter, returned with
them. This is a great day for our history!
_June 27._--Mr. Beamish was able to get to the frames, which he
found firm and undisturbed.
A small tarpaulin was now spread over the frames, and operations
commenced for cleaning them. This was a most difficult and dangerous
work, especially as the water was still so high that the frames could
only be approached by boats. The men, even the best hands, were at first
greatly alarmed at the danger they were in; but the example set by Mr.
Brunel and Mr. Beamish produced, as Sir Isambard notes, the best effect,
and they soon became reconciled to their situation.
_July 7._--Very uncomfortable in the frames; the candles cannot
burn, the ventilation cannot act. Isambard went several times
to-day down in the diving-bell. On one occasion the chain slipped
through the stoppers, but most providentially it jammed itself
tight before being altogether run out. _The consequence might
indeed have been fatal._ Can there be a more anxious situation than
that which I am constantly in? Not one moment of rest either of
mind or body. Mr. Beamish always ready. Poor Isambard always at his
post too, alternately below, or in the barges, and in the
diving-bell.
On July 11, Sir Isambard thought that matters had so far advanced that a
large tarpaulin, which it was proposed to sink over the frames, ‘would
have its full effect.’ It was accordingly sunk on the following day,
under the superintendence of Mr. Brunel. Sir Isambard adds to his
account of the operation--‘This reflects great credit on Isambard, and
the apparent facility with which it was effected evinces his presence of
mind, for a single _faux pas_ would have spoilt the whole.’[21]
_July 21._--During the early part of the night an alarm was given,
by Fitzgerald calling for clay wedges, and exclaiming that the
whole of the faces were coming in altogether. Rogers collected a
quantity of wedges to go to the frames, but no boat was to be seen.
He called to the men in the frames, but received no answer. Taking
the small boat in the east arch, he reached the frames, but found
nobody, nor any appearance of derangement in the ground.
Conjecturing they might be drowned, he explored further, and saw
the four men stretched on the small stage, not drowned, but sound
asleep!
_July 26._--Water nearly out of the arches. For the first time we
could walk to the frames--a most gratifying circumstance indeed!
_Two months and eight days._
_September 30._--How slow our progress must appear to others; but
it is not so, if it is considered how much we have had to do in
righting the frames and in repairing them; what with timbering,
shoring, shipping and refitting--all these operations being in
confined situations, the water bursting in occasionally, and the
ground running in: in short, it is truly terrific to be in the
midst of this scene. If to this we add the actual danger, magnified
by the re-echoing of the pumps, and sometimes (still more awful
warning!) the report of large pieces of cast iron breaking, it is
in no way an exaggeration to say that such has been the state of
things. Nevertheless, my confidence in the shield is not only
undiminished--it is, on the contrary, tried with its full effect,
and it is manifest now that it will soon replace us in good
ground, and in a safe situation. No top staves have given way. That
is our real protection.
_October 17._--At 2.15 A.M. Kemble, having first called upon
Gravatt, came to Isambard in a hurry, and, quite stupefied with
fright, told him that the water was in. Says Isambard--‘I could not
believe him. He said it was up the shaft when he came. This being
like positive, I ran without a coat as fast as possible, giving a
double knock at Gravatt’s door in my way. I saw the men on the top,
and heard them calling earnestly to those whom they fancied had not
had time to escape. Nay, Miles had already, in his zeal for the aid
of others, thrown a long rope, and was swinging it about, calling
to the unfortunate sufferers to lay hold of it, encouraging and
cheering those who might not find it, to swim to one of the
landings. I immediately, I should say instantly, flew down the
stairs. The shaft was completely dark. I expected at every step to
splash into the water. Before I was aware of the distance I had
run, I reached the frames in the east arch, and met there
Pamphillon, who told me that nothing was the matter, but a small
run in No. 1 top, where I found Huggins and the _corps d’élite_.
They were not even aware that any one had left the frames. The
cause of the panic was one of the labourers; hearing the man in No.
1 call for Ball, he ran away, jumping off the stage, crying, “_Run,
run, murder, murder; put the lights out._” His fellow-labourers
followed like sheep, making the same vociferations.’
_November 10._--Isambard gave his entertainment to nearly forty
persons, who sat at table in the Tunnel. Nothing could exceed the
effect for brilliancy. About 120 men partook of a dinner in the
adjoining arch.
As the year drew to a close, the difficulty of working the silt
increased, and with this difficulty increased also the expense of
maintaining the staff of men required. On December 18, Mr. Brunel,
writing for his father, who was absent from town for a few days, thus
describes the nature of the soil through which they were then passing.
The state of the ground over Nos. 1, 2, and 3 top has caused
considerable delay, particularly this week, although not such as to
give any cause of anxiety as to our future rate of progress, or to
have any serious effect except the increased expense incidental to
this delay. My father desired me to describe to the Board the
causes of these difficulties. There is a considerable spring at
this point, and a corresponding soft part in the bed of the river,
which seems to indicate the rising of the spring. The ground in the
neighbourhood is affected by this spring in rather a peculiar
manner: at the half-flood tide the pressure is greatest: dry hard
clay oozes with great force through openings hardly observable, the
silt and water running by starts. At high-water the pressure and
quantity of water begin to diminish and on the ebb-tide the ground
is hard and dry, and can be worked with ease. On the flood-tide
there are as many as twelve and fifteen of the best hands, besides
myself (or one of my assistants) and the foreman, engaged entirely
at one face.
On January 1, 1828, Sir Isambard returned to London; and on the 12th,
when about 600 feet of the Tunnel had been completed, a second irruption
occurred, which put a stop to the works for seven years.
The particulars of this accident are thus described by Mr. Brunel, in a
letter to the Directors of the Company:--
I had been in the frames (shield) with the workmen throughout the
whole night, having taken my station there at ten o’clock. During
the workings through the night, no symptoms of insecurity appeared.
At six o’clock this morning (the visual time for shifting the men)
a fresh set or shift of the men came on to work. We began to work
the ground at the west top corner of the frame: the tide had just
then begun to flow; and finding the ground tolerably quiet, we
proceeded by beginning at the top, and had worked about a foot
downwards, when on exposing the next six inches, the ground swelled
suddenly, and a large quantity burst through the opening thus made.
This was followed instantly by a large body of water. The rush was
so violent as to force the man on the spot, where the burst took
place, out of the frame (or cell) on to the timber stage behind the
frames. I was in the frame with the man, but upon the rush of the
water I went into the next box (or cell), in order to command a
better view of the irruption, and seeing that there was no
possibility of then opposing the water, I ordered all the men in
the frames to retire. All were retiring, except the three men who
were with me, and they retreated with me. I did not leave the stage
until those three were down the ladder of the frames, when they and
I proceeded about twenty feet along the west arch of the Tunnel. At
this moment the agitation of the air, by the rush of water, was
such as to extinguish all the lights, and the water had gained the
height of our waists. I was at that moment giving directions to the
three men, in what manner they ought to proceed in the dark to
effect their escape, when they and I were knocked down, and covered
with a part of the timber stage. I struggled under water for some
time, and at length extricated myself from the stage, and by
swimming and being forced by the water, I gained the eastern arch
where I got a better footing, and was enabled by laying hold of the
railway rope, to pause a little, in the hope of encouraging the men
who had been knocked down at the same time with myself. This I
endeavoured to do by calling to them. Before I reached the shaft
the water had risen so rapidly that I was out of my depth, and
therefore swam to the visitors’ stairs, the stairs for the workmen
being occupied by those who had so far escaped. My knee was so
injured by the timber stage that I could scarcely swim, or get up
the stairs, but the rush of the water carried me up the shaft. The
three men who had been knocked down with me were unable to
extricate themselves, and I am grieved to say, they are lost; and I
believe also two old men, and one young man, in other parts of the
work.
This statement Sir Isambard embodied in a report to the Directors of
January 28, which was circulated among the proprietors.
As soon as the first excitement caused by the irruption had ceased, Mr.
Brunel directed the diving-bell to be prepared in order to ascertain the
state of the shield and the extent of the disturbance of the bed of the
river caused by the rush of water into the Tunnel.
He was, however, so seriously injured that he could not actively
superintend the preparations, but his orders were given with his usual
clearness, calmness, and decision; and as soon as the barge containing
the diving-bell was properly moored over the Tunnel, he was carried out
and laid upon a mattress on the deck of the barge, that he might direct
what was to be done.
As evening came on he became so much worse that he was taken into the
cabin; but everything which took place was reported to him.
At length, the bell being ready, it was lowered early on the Sunday
morning, but the chain not being long enough, proceedings were delayed
until a longer chain could be obtained.
As, however, a chain of the right size and length could not be obtained,
the strongest cable which could be procured in the neighbourhood was
substituted for the chain. A controversy then arose between the
assistant engineers and the foremen as to the sufficiency of the
strength of the cable; and it was agreed to consult and to abide by the
opinion of Mr. Brunel, who was then lying in great pain in the cabin.
No answer could be obtained from him for some minutes, and then he only
said, ‘Don’t go down.’ This not being satisfactory to the advocates of
the sufficiency of the cable, it was agreed to lower the bell empty,
which was done, and it was brought up safely; but just as it was swung
over the barge, the rope broke and the bell fell on to the stage.
The next day Mr. Brunel was taken home, when it was found that, besides
the injury to his knee which he received while endeavouring to save the
lives of the three men who were with him,[22] he had received serious
internal injuries, which kept him under medical treatment for several
months.
When he was able to return to Rotherhithe all hope of continuing the
works was for the time abandoned. When they were resumed, in 1835, he
was entirely engrossed in the independent pursuit of his profession;
and, with the exception of a few occasions when he acted for his father,
he had no further connection with the Tunnel.
It is not, therefore, necessary to continue the narrative in detail; but
a brief summary of the subsequent history of the enterprise may be
interesting to those who are unacquainted with it.
The Tunnel was cleared of water, and efforts were made, unfortunately
without success, to raise funds for the completion of the undertaking.
Great enthusiasm was exhibited by the general public and by many eminent
persons, including the Duke of Wellington; but the money was not
forthcoming, and nothing was left but to brick in the shield, and wait
for more favourable times.
It was not till the beginning of 1835 that the Company was able, by the
aid of a loan from Government, to recommence the works. The old shield
was removed and a new one substituted, in which considerable
improvements were introduced. Slings connecting the frames were added,
which enabled each frame to support its neighbours when necessary, and
important alterations were also made in the arrangements for keeping the
frames at the right distance from one another, and for giving greater
facility of adjustment to the various parts.
Before the Wapping side was reached there were three more irruptions of
the river, namely, August 23, November 3, 1837, and March 21, 1838; but
in October 1840 the shaft on the Wapping shore was commenced. It
differed from the Rotherhithe shaft, in being sunk the whole depth
without underpinning, and was made of a slightly conical form, to reduce
the friction in sinking, and had a larger quantity of iron hoops
introduced into the brickwork, in order to increase its strength. When
this structure had been sunk to the required depth (70 feet), the
excavation of the Tunnel was resumed, and at last the shield was brought
up to the brickwork of the shaft. The operation of making the junction
between the Tunnel and the shaft was one of much difficulty, but it was
at length satisfactorily accomplished, and the Tunnel was opened to the
public on March 25, 1843--eighteen years and twenty-three days after the
commencement of the work.[23]
Sir Isambard Brunel, whose health had for some time been failing, now
retired altogether from his professional labours. After passing a few
years in peaceful and happy seclusion, surrounded by those he loved, and
watched over by their affectionate care, he died on December 12, 1849,
in his 81st year, having been spared to carry to completion his greatest
work, and to see his son following in his footsteps with a success which
must have exceeded his most sanguine expectations.
* * * * *
The education Mr. Brunel received from his father was well calculated to
form the foundation of his future career. During the later and more
arduous part of the contest, which was ended by the irruption of January
1828, he held both the nominal and actual post of Resident Engineer of
the Thames Tunnel; but from the commencement of the works, when he was
only nineteen years old, he had been, as stated by Sir Isambard, ‘a most
valuable coadjutor in the undertaking.’ While placed in this responsible
position he acquired habits of endurance and of self-reliance, and
learnt to act with promptitude and decision in the application of those
measures which experience had shown to be effective in each particular
class of emergency. But beyond all other advantages, he had before him
the example of his father’s character, in which a rare degree of
gentleness and modesty of disposition was joined to unflinching energy,
and a determination to overcome all difficulties.
NOTE A (p. 5).
_The Bourbon Suspension Bridges_.[24]
The suspension bridges designed by Sir Isambard Brunel for crossing
rivers in the Ile de Bourbon were two in number. One of them had two
spans of 122 feet each in the clear, and 131 feet 9 inches between the
points of suspension of the chains. The second had but one span of the
same dimensions as those of the larger bridge. In the design of these
bridges one of the most important points to be attended to, was to
render them secure against hurricanes, which are both frequent and
severe in the Ile de Bourbon.
In the larger bridge there was a pier of masonry, built in the middle of
the river up to the level of the roadway of the bridge. The suspension
chains of the bridge were in three groups, 9 feet 8 inches apart, so as
to leave room for two roadways, each about 8 feet 9 inches wide. Each of
these groups of chains consisted of two chains side by side. Each chain
was made with long links like those of the chain cables used for
moorings.
These links, which were made of iron 1·36 inch in diameter, were 4 feet
8 inches long, inside measure, and were each connected together by two
short coupling links, 8¾ inches long, inside measure, of iron 1·36 inch
by 1 inch, and two pins, each two inches in diameter.
The two chains of each group were placed side by side, with the links
upright; one of the pins at each joint was made long enough to serve for
both chains, and, in the middle of its length between the two chains,
was passed through an eye at the upper end of one of the suspending rods
of the bridge. Thus to every joint in each group of the main chains, or
at intervals of about 5 feet, there was a suspending rod. These rods
were 1¼ inch in diameter.
The pins of the joints of the main chains had half heads at each end of
them. They could thus be easily inserted in erecting the bridge, but
once in place were quite secure. At every fourth joint in the main
chains one of the joint pins was made in two halves, with wedges
inserted between them for adjusting the length of the main chains.
Thus there were six chains, and as the links of these had each two parts
of iron 1·36 inch in diameter, the total sectional area of the six
chains was 17·4 inches.
Each group of the main chains was supported at a height of 25 feet 6
inches above the roadway at the centre pier, and at a height of 5 feet 3
inches at each of the side piers, the lowest portion of the curve of the
chain being about 1 foot below the points of suspension of the side
piers.
The upright standards, carrying the chains both at the centre pier and
at the side piers, consisted for each group of chains of a triangular
framework of cast iron, strengthened by long bolts of wrought iron.
There were thus three of these triangular frames parallel to each other
at each of the piers, and those at the centre pier were braced together
over the carriage road. The main chains were not bolted to the
standards, but were slung from them by a vertical suspension link, which
thus allowed them to move a little lengthways. This link, in fact,
performed the function of the rollers now generally put under the
saddles of suspension bridges.
The ends of the main chains were held by back stays, formed of bars 3
inches broad by 1¼ inch thick, and 10 feet long, with joints made with
short links, and 2⅜ inch pins. The ends of those back stays were
secured to holding down plates 3 feet in diameter, sunk deep in the
ground and well loaded.
As there was a vertical suspension rod at each joint of the main chains,
there was a suspension rod hanging from each of the three groups of
chains at about every five feet of the length of the bridge. To each set
of these rods was attached a cross girder of cast iron of a =T= section,
with a large rounded bead at the lower edge of the upright web; and
connecting these under each of the main chains was a longitudinal timber
beam about 8 inches square.
The cast-iron cross girders carried longitudinal teak planking, the
planks on which the carriage wheels ran being 12 inches wide and 4
inches thick, protected at the top by wrought-iron plates running
longitudinally. The horse-path was protected by iron plates arranged
crosswise.
Under each span of the bridge were four chains curved upwards and also
sideways. These chains were fastened at their ends into the piers, and
were connected to the roadway by ties drawn up tight and attached to the
main longitudinal bearers of the platform; the object being to stiffen
the platform.
These under tie chains were made each of a set of rods 1¼ inch in
diameter with eyes at their ends, the ends being connected by short
joint links and 1¼ inch pins; and to these joint links were attached the
tie rods which connect these inverted chains with the platform of the
bridge, and so prevented its being lifted or blown sideways by the force
of the wind.
In the smaller bridge, which, as has been said, consisted of one span of
131 feet 9 inches between the points of suspension, these points were 15
feet 5 inches above the roadway, and the lowest part of the chain was 9
feet 7 inches below the points of suspension. The details of this bridge
were similar to those of the larger one.
NOTE B (p. 5).
_Experiments with Carbonic Acid Gas._
In 1823 Mr. Faraday made the important discovery that under certain
conditions of temperature and pressure many gases could be liquefied,
and that these liquids exerted great expansive force by slight additions
of temperature, returning quickly with regularity and certainty to their
original state upon the application of cold.
The discovery of this new force appeared of such importance, that Mr.
Faraday lost no time in publishing it to the world; and Sir Isambard
Brunel very soon afterwards commenced a series of experiments to
determine the value of the liquid gas as a mechanical agent.
The first experiments were made at Chelsea; but the prosecution of them
was soon transferred to the care of Mr. Brunel at Rotherhithe, where he
devoted all his spare time to the construction of his father’s proposed
‘Differential Power Engine.’
That the progress of this discovery, and of the experiments made with a
view to the application of the liquid gas, as a motive power, may be
understood, it is necessary to state that in March 1823 Mr. Faraday
communicated to the Royal Society the results of his first experiments
on the liquefaction of gases.
The fluid was then produced by the decomposition of the hydrate of
chlorine by heat in a closed tube, the amount of gas evolved being so
great as to produce a pressure in the tube sufficient to condense the
gas into a fluid of the same volume.
This interesting experiment was followed by others with that rapidity
and success so remarkable in everything undertaken at that time in the
laboratory of the Royal Institution; and within a month another paper
was read before the Royal Society, in which the degrees of pressure and
temperature at which several gases could be liquefied were recorded, and
the means employed to produce and liquefy each gas accurately described.
On April 17 a third paper was communicated by Mr. Faraday, ‘On the
Application of Liquids produced by the Condensation of Gases as
Mechanical Agents.’
The question is thus stated: ‘The ratio of the elastic force dependent
upon pressure is to be combined with that of the expansive force
dependent on temperature; and the development of latent heat on
compression and the necessity of its reabsorption in expansion must
awaken doubts as to the economical results to be obtained by employing
the steam of water under very great pressures and very elevated
temperatures.
No such doubt can arise respecting liquids, which require for their
existence even a compression equal to thirty or forty atmospheres, and
where slight elevations of temperature are sufficient to produce an
immense elastic force, and where the principal question arising is
whether the effort of mechanical motion is to be most easily produced by
an increase or diminution of heat by artificial means.’
Difficulties were suggested by Mr. Faraday as to the possibility of
obtaining sufficient strength in the apparatus, but the small difference
of temperature required to produce an elastic force of many atmospheres,
he considered would render the risk of explosion small.
To construct the machinery whereby this new force could be practically
applied as a substitute for steam, occupied the time of Sir Isambard
Brunel and his son at intervals for several years; for although Mr.
Brunel was satisfied at an early period of the enquiry that the
liquefied gases could only be advantageously employed where the cost of
motive force was secondary to economy of space and to the avoidance of
the cumbrous apparatus required for the use of steam, still he was so
impressed with the importance of the subject, if the difficulties he
foresaw in its application could be overcome, that he continued his
experiments for a long period with unflagging energy and perseverance.
The facts relating to the liquefaction of the gases, their elastic force
when liquefied under different temperatures, the rapidity with which
they could be alternately expanded and condensed, and the best mode of
producing each gas, were determined by Mr. Faraday; and as Mr. Brunel
was at that time attending the morning chemical lectures at the Royal
Institution, he was in constant communication with him, and thoroughly
conversant with his experiments.
After Mr. Brunel had made a few preliminary experiments, Sir Isambard
determined to employ liquefied carbonic acid gas for the motive power of
the proposed new engine, the facility and cheapness of its production,
its great expansive force, and its neutral character distinguishing it
from any other gas; but it was long before vessels were constructed, in
which gas could be produced in sufficient quantity and purity to exert
the force required to liquefy it in its own volume, for it was soon
found to be impossible to obtain the required pressure with pumps.
Carbonate of ammonia and sulphuric acid were the elements used, and the
generator was so arranged that it could be charged, emptied of
atmospheric air, and the joints made perfect, before the commencement of
the formation of the gas which was to be liquefied.
To the generator was attached a receiver, which could be surrounded with
a freezing mixture, so that the temperature of the gas in the cylinder
might be below that in the generator.
The gradual formation of the liquid, the development of its elastic
force, and the regularity and rapidity with which it increased or
diminished by each degree of heat or cold, were carefully watched
through a glass gauge, and the receiver when filled with liquid could be
disconnected from the generator.
The mechanical difficulties as they arose, one after the other, in the
construction and arrangement of the various parts of the generator and
receiver were at length overcome; and the receiver was not only filled
with liquid gas, but found to be capable of retaining it, whether
exerting an elastic force of 30 atmospheres at ordinary temperatures, or
of 100 atmospheres when subjected to a slight degree of heat.
The receiver being satisfactorily completed, the next object of
attention was the design and construction of a working cylinder capable
of resisting at least 1,400 lbs. pressure on the square inch; a task
which was one of great anxiety, as any weakness might have caused a
serious accident.
It was only after the trial of every known method of making joints to
resist high pressures had failed, that an arrangement was devised,
requiring the most perfect workmanship, by which packing of any kind was
dispensed with, and the cylinder fitted for use.
With the improved tools of the present day it is not easy to realise the
difficulties, delays, and disappointments which forty-five years ago
occurred from the failure, first of one part of a joint, and then of
another; but the construction of vessels capable of producing and also
of retaining the gas in its liquid state, with the means of alternately
expanding and condensing it from thirty or forty to eighty or one
hundred atmospheres, having been accomplished, the object of the
expenditure of so much labour and inventive power appeared to be within
reach.
The construction of the machinery to utilise the elastic force contained
in the cylinder was now proceeded with. Day by day new difficulties
arose, and each as it was successfully met seemed but to leave another
of greater importance to be surmounted.
It is not necessary in this Note to describe the various arrangements
which were devised for transferring the great elastic force in the
cylinder of small diameter to a piston in another cylinder of much
larger dimensions; it is sufficient to say, that after the devotion of
much valuable time extending over several years, and a very large
expenditure of money, and after carefully considering the cost of the
liquid carbonic acid gas, the difficulty of preventing waste, and the
necessarily very expensive character of the machinery, Mr. Brunel was
satisfied ‘that no sufficient advantage in the sense of economy of fuel
can be obtained by the application of liquefied carbonic acid gas as a
motive power’; but so thoroughly did he exhaust the subject before he
committed himself to this opinion, that no one has since renewed the
enquiry or attempted to make a machine to be moved by the elastic force
of liquefied gases, the construction of which, it was well known, had
baffled the inventive genius of Sir Isambard Brunel and his son.
CHAPTER II.
_THE CLIFTON SUSPENSION BRIDGE._
A.D. 1829--1853. ÆTATIS 24--48.
ORIGIN OF THE UNDERTAKING--THE FIRST COMPETITION, NOVEMBER
1829--DESCRIPTION OF MR. BRUNEL’S PLANS--MR. TELFORD’S DECISION AS
UMPIRE--MR. TELFORD’S DESIGN--THE SECOND COMPETITION--MR. BRUNEL
APPOINTED ENGINEER, MARCH 1831--COMMENCEMENT OF THE WORKS, AUGUST
1836--DESCRIPTION OF THE DESIGN--ABANDONMENT OF THE WORKS,
1853--FORMATION OF A NEW COMPANY AND COMPLETION OF THE BRIDGE,
1864. _NOTE_: THE HUNGERFORD SUSPENSION BRIDGE.
After Mr. Brunel had recovered from his accident in the Thames Tunnel,
he went for a trip to Plymouth, where he examined with great interest
the Breakwater and other engineering works in the neighbourhood. He
notes in his diary that he went to Saltash, and that he thought the
river there ‘much too wide to be worth having a bridge.’ This remark was
no doubt made in consequence of his father having some years before been
consulted as to the construction of a suspension bridge at this place,
which Mr. Brunel himself, eighteen years afterwards, selected for the
crossing of the Tamar by the Cornwall Railway, and built there the
largest and most remarkable of his bridges.
For the remainder of the year 1828, and during the greater part of 1829,
Mr. Brunel kept himself fully employed in scientific researches, and in
intercourse with Mr. Babbage, Mr. Faraday, and other friends; but he was
without any regular occupation, until, in the autumn of 1829, he heard
that designs were required for a suspension bridge over the Avon at
Bristol, and he determined to compete.
This project originated in a bequest made in 1753, by Alderman William
Vick, of the sum of 1,000_l._ to be placed in the hands of the Society
of Merchant Venturers of Bristol, with directions that it should
accumulate at compound interest until it reached 10,000_l._, when it was
to be expended in the erection of a stone bridge over the river Avon,
from Clifton Down to Leigh Down. Alderman Vick stated that he had heard
and believed that the building of such a bridge was practicable, and
might be completed for less than 10,000_l._
* * * * *
The legacy was duly paid to the Society of Merchant Venturers, and
invested by them. The interest accumulated; and in 1829, when the fund
amounted to nearly 8,000_l._, a committee was appointed to consider in
what way it would be possible to carry out Alderman Vick’s intentions.
An estimate for a stone bridge was procured, but as it gave the cost at
90,000_l._, it was evident that this scheme must be abandoned.
* * * * *
The committee then advertised for designs for a suspension bridge. Mr.
Brunel, on hearing through a friend of the proposed competition, went to
Bristol; and, after examining the locality, he selected four different
points within the limits prescribed by the instructions of the
committee, and made a separate design for each of them. His plans were
sent in on the day appointed, Nov. 19, 1829, with a long statement, from
which the following description of them is taken.
The first design was for a bridge of 760 feet span between the points of
suspension, the length of the suspended floor being 720 feet. In order
to obtain a height of 215 feet above high-water mark (which was the
least that the levels allowed of), towers 70 feet high would have had to
be built on the cliffs to carry the chains. The total length of chain,
including the land-ties, was about 1,620 feet. Mr. Brunel did not
approve of this design, as the situation was not favourable to
architectural effect, a point to which the committee attached great
importance; but he suggested it from its being somewhat more economical
in construction than his other plans.
In another design, the situation being some way farther down the river
than that of the design last mentioned, towers would also have been
necessary. The distance between the points of suspension was 1,180 feet,
with a suspended floor of over 900 feet. It is probable that Mr. Brunel
only proposed this plan because the site came within the limits of
deviation, as he does not say anything in favour of it in his report.
The two remaining plans are the most interesting of the series, as there
can be no doubt that, if Mr. Brunel had had his own way, he would have
adopted one of them for execution; and it appears from a little sketch
on the top of one of his earliest letters from Bristol, that his first
idea for the bridge was that which is carried out in these two designs.
The site selected was one where the rocks rise perpendicularly for a
considerable height above the proposed level of the bridge, and
therefore piers and land-ties were dispensed with, the chains being hung
directly from the rock. No masonry was required except for architectural
effect.[25]
[Illustration: CLIFTON SUSPENSION BRIDGE.
Plate I.
Fig. 1.
Elevation of Drawing Nº 3 of Mr. Brunel’s Designs in the first
competition. AD. 1829
Fig. 2.
H. Adlard So.
Elevation of the Bridge according to the Design on which the works were
commenced. AD. 1836.]
The principal difference between these two designs is that in the second
a short tunnel is avoided at one end. The style of architecture selected
for the tunnel-front and the face of the rock, as shown on the drawings
sent in to the committee, is Norman. There are also extant many
beautiful sketches made by Mr. Brunel for different parts of the
design.[26]
In determining upon the mode of construction, which was the same in the
four designs, Mr. Brunel acted upon the principle which guided him in
all his subsequent undertakings, which was, as he states in his report,
‘to make use of all that has been found good in similar works, and to
avail himself of the experience gained in them, and to combine with all
their advantages the precautions which time and experience had pointed
out.’
He dismissed in a few words the plan of breaking the span into two or
three lengths. This was in his opinion unnecessary, and he computed that
the cost of a pier built up from the water’s edge to sufficient height
above the bridge to carry the chains, would be at least 10,000_l._ For
this reason he recommended the adoption of spans, the smallest of which
far exceeded any up to that time constructed.
In designing the chains, he dispensed with the short connecting links,
which had been previously adopted in suspension bridges, introducing
instead the method now universally used, of connecting each set of links
directly with the adjoining one by means of a pin passed through the
holes of both. The number of joints and pins was thus reduced one half,
and a considerable saving of expense, as well as diminution of weight,
effected.
Another improvement, which diminished still further the weight of the
chains, was making the links in lengths of 16 feet, or nearly double
that of the longest links at the Menai bridge. The chief reason for this
alteration was to ensure a near approximation to equality in the strains
on the different links, should all the distances between the holes not
be exactly equal. This improvement was afterwards carried still further
in the Hungerford Suspension Bridge, the links of which were 24 feet
long.[27]
Mr. Brunel also intended to introduce equalising beams in the supports
of the floor, so that each chain should bear an equal share of the load.
By this arrangement, there would have been comparatively few points of
suspension, and ‘the view of the scenery would not be impeded from the
observer being surrounded by a forest of suspension rods.’
The disturbance of the strains on the links arising from the greater
expansion of the metal of the outer links by the direct heat of the sun,
he proposed to obviate by sheet-iron plates placed on each side of the
chains, but separated from them by a small interval, and thus screening
them from the heat. He did not, however, use this protecting covering at
the Hungerford bridge.
All the designs show a camber or rise in the centre of the platform of
the bridge, to the extent of two or three feet; and the main chains are
brought down almost to the level of the platform. To this last
arrangement, as tending to prevent undulation, Mr. Brunel attached some
importance; and he further intended to stiffen the bridge against the
action of high winds by a system of transverse bracing, and by the
addition of inverted chains, similar to those used with success by his
father in the Bourbon bridges.[28]
Such, then, were the main features of the bold and carefully matured
designs placed by Mr. Brunel before the committee. Out of twenty-two
plans submitted, only those of Mr. Brunel and four other competitors
were deemed worthy of consideration. He and his friends were naturally
much gratified at this, and were full of hope for his ultimate victory.
But now, when he seemed to have a fair chance of success in a contest
which he justly deemed would have a most important bearing upon his
future professional career, an obstacle presented itself, which for the
time seemed almost insurmountable; for he met with an unexpected
opponent in Mr. Telford, the foremost engineer of the day, and the
designer of the famous suspension bridge over the Menai Straits.
The committee of the Society of Merchants had, not unnaturally, found
themselves unable to decide upon the merits of designs for a suspension
bridge, and had asked Mr. Telford to act as their adviser in the matter.
Unfortunately for Mr. Brunel, Mr. Telford was of opinion that the
maximum span admissible was that of the Menai bridge, _i.e._ under 600
feet, and that Mr. Brunel’s proposed bridge, though very pretty and
ingenious, would most certainly tumble down in a high wind.
This decision was, of course, fatal to the success of any design which
substituted one large span for two or more smaller ones, and dispensed
with pillars. Mr. Brunel therefore obtained permission to withdraw his
plans from the competition.
Mr. Telford then reported to the committee that none of the remaining
designs were suitable for adoption without the introduction of such
material alterations as would, in fact, constitute a new design.
Whereupon the committee took the only course which, under the
circumstances, was open to them, and requested Mr. Telford to prepare a
design himself.
Mr. Brunel was not a little disappointed at the turn matters had taken;
but, having, as he said,‘smoked away his anger,’ he took leave of his
friends at Bristol, and went for a visit to some of the principal
manufacturing towns in the north.
Meanwhile Mr. Telford prepared his design, and it was exhibited in
Bristol in January 1830. It consisted of a suspension bridge of three
spans (the centre span 360 feet, and the side ones 180 feet each), the
chains being supported at the intermediate points by tall stone piers
rising from the river’s banks at just sufficient distance apart to avoid
interfering with the roadways on either side of the stream. The style of
architecture was a florid Gothic; and, in order to display the peculiar
features of that style, the faces of the piers were covered with
elaborate panelling, and the chains ornamented with fret-work.
This design was received with a flourish of trumpets; numerous
engravings were published, exhibiting the bridge from various points of
view, and ‘thousands of copies were disposed of;’ but, after a time, it
would appear that the captivating effect of the Gothic belfries wore
off, and that the more the citizens of Bristol looked at Mr. Telford’s
plan, the less they were satisfied with it; for, although it was
deposited in the Private Bill Office, on application being made for an
Act of Parliament, the trustees who were appointed under the Act
determined to invite a second competition.
On this occasion, Mr. Telford appeared as a competitor and not as a
referee, that office being filled by Mr. Davies Gilbert, sometime
President of the Royal Society.
The site of the bridge was fixed, being that selected by Mr. Telford;
but the trustees expressly left it to the judgment of the competitors to
decide whether there should be intermediate piers or one unbroken span.
Of the thirteen designs sent in, five, including those submitted by Mr.
Telford and Mr. Brunel, were reserved for further examination. On March
17, 1831, Mr. Davies Gilbert (who had been assisted by Mr. Seward) made
his report. Mr. Telford’s design was put aside, ‘on account of the
inadequacy of the funds requisite for meeting the cost of such high and
massive towers as were essential to the plan which that distinguished
individual had proposed.’
Mr. Brunel’s design was placed second.[29] Although Mr. Gilbert reported
that it presented every desirable strength and security, he saw
objections to many of the details, and therefore did not recommend it
for adoption. However, on the following day, March 18, he stated to the
trustees that he had seen Mr. Brunel, and that it gave him much pleasure
to state that the explanations made by Mr. Brunel had materially altered
his views as to the details of the plans, which he (Mr. Gilbert) was now
satisfied were quite equal to those which he had placed first, and that,
considering the superiority of Mr. Brunel’s design in the essential
particular of strength, he should judge it preferable to any of the
others.
Thereupon the trustees, ‘having considered Mr. Davies Gilbert’s report,
and referred to all the plans, including Mr. Telford’s, unanimously gave
the preference to Mr. Brunel’s,’ and appointed him their engineer.
Subscriptions came in but slowly, and it was not till 1836 that the
works were commenced.
The first stone of the abutment on the Leigh woods or Somersetshire side
of the river was laid on August 27 by the Marquis of Northampton,
President of the British Association, which was then holding its meeting
in Bristol.[30]
The span of the bridge is greater than that of Mr. Brunel’s design for
the second competition, but much less than the spans of the earlier
designs, to which he had given the preference.[31] On this point, as
well as on the question of site, he had to conform to the wishes of the
trustees.[32] The span approved of by them necessitated the building of
a very large abutment on the Leigh woods side, the height of which, from
the surface of the rock to the level of the roadway, is 110 feet. Above
the roadway, the tower to carry the chains is built to a height of 86
feet. On the Clifton side, the base of the tower is formed by one of the
boldest of the range of St. Vincent’s rocks, which here rise almost
perpendicularly to a height of 230 feet above high water, and
consequently a very small abutment was required. The tower on this side
is 3 feet higher than that on the Leigh woods side, and the roadway has
a general inclination of about 1 in 233. Mr. Brunel thought that if the
roadway were level, it would have the appearance of falling towards
Clifton, owing to the ground there being precipitous, while on the
Leigh woods side it is sloping.
He intended, in the construction of the bridge, to have followed out the
ideas embodied in his report of 1829, and would have preferred to have
had only one chain on each side of the bridge, and that much stronger
than was usually adopted; but, in deference to public opinion, he put
two chains, though he doubted if they would expand equally. ‘A rigid
platform would in some degree prevent the unequal distribution of load
thus caused, but he endeavoured to lessen the effect of unequal
expansion by arranging a stirrup at the top of each suspending rod, so
as to hold equally at all times on both chains, and thus to cause each
to sustain its proportion of the load.’
The road platform was to have had beneath it ‘a complete system of
triangular bracing, which would render it very stiff.’
In order to lessen the action of wind on the bridge, he brought down the
main chains in the centre nearly to the level of the platform, and
intended to apply the system of brace chains at a small angle to check
vibration. There were, moreover, to be two curved chains lying
horizontally, and attached underneath the platform, so as to resist the
lateral action of the wind.[33]
He here introduced movable saddles to carry the chains on the top of the
towers, with rollers running on perfectly flat and horizontal roller
beds.[34] By this arrangement no pressure except a vertical one could
come on the towers.
He also devised means, by levers and hydraulic presses, for relieving
the rollers and roller beds from pressure, in the event of their
requiring renewal.
Mr. Brunel ultimately determined to adopt the Egyptian style of
architecture. His brother-in-law, Mr. John Callcott Horsley, R.A., gives
the following account of the proposed designs for the towers:--
‘His conception of the towers or gateways at either end of the bridge
was peculiarly grand and effective, as may be seen from his sketches
still existing. They were to be purely Egyptian; and, in his design, he
had caught the true spirit of the great remains at Philæ and Thebes. He
intended to case the towers with cast iron, and, as in perfect
accordance with the Egyptian character of his design, to decorate them
with a series of figure subjects, illustrating the whole work of
constructing the bridge, with the manufacture of the
materials--beginning with quarrying the iron ore, and making the iron,
and ending with a design representing the last piece of construction
necessary for the bridge itself. The subjects would have been arranged
in tiers (divided by simple lines) from top to bottom of the towers, and
in the exact proportion of those found upon Egyptian buildings. He made
very clever sketches for some of these proposed figure subjects, just to
show what he intended by them. I remember a group of men carrying one of
the links of the chainwork, which was excellent in character. He
proposed that I should design the figure subjects, and he asked me to go
down with him to Merthyr Tydvil, and make sketches of the iron
processes. We accomplished our journey, and all the requisite drawings
for the intended designs were made.’
The works were commenced with the Leigh abutment, which was completed in
1840, great delay having been caused by the failure of the contractors.
This misfortune led to a large excess of expenditure over the original
estimates. In 1843 the whole of the funds raised (amounting to
45,000_l._) were exhausted, and there still remained to be executed the
ornamental additions to the piers (the cost of which was estimated at
about 4,000_l._), half of the iron work, the suspension of the chains
and rods, the construction of the flooring, and the completion of the
approaches, &c., the estimate for the execution of which was 30,000_l._
Unfortunately, all efforts to raise further subscriptions were
unsuccessful; and in July 1853, when the time limited for the completion
of the bridge had expired, the works were closed in, and the undertaking
abandoned.[35]
Several proposals for completing the bridge were made in Mr. Brunel’s
lifetime, and he took every opportunity of furthering this object, which
he had very much at heart. It was not, however, till about a year after
his death that the superstructure of the bridge was actually commenced.
A company was formed in 1860 by some of the principal members of the
Institution of Civil Engineers, ‘who had an interest in the work as
completing a monument to their late friend Brunel, and at the same time
removing a slur from the engineering talent of the country.’[36] Mr.
John Hawkshaw, F.R.S., and Mr. W. H. Barlow, F.R.S., were appointed the
engineers, and Mr. Brunel’s old friend Captain Christopher Claxton,
R.N., the secretary. The works were carried on with vigour; and the
bridge was opened with much ceremony on December 8, 1864.
The chains were brought from the Hungerford Suspension Bridge, then in
process of demolition. A description of the Hungerford bridge will be
found in the note to this chapter.[37]
Although the Clifton bridge was not completed by Mr. Brunel, his
connection with it forms a very important passage in the history of his
life. Doubtless, if he had never heard of the proposed competition in
1829, or if he had been one of the disappointed competitors, he would
have found some other opportunity of making a name in his profession;
but, as a matter of fact, the Clifton bridge competition did give him
the opportunity he desired, and all his subsequent success was traced by
him to this victory, which he fought hard for, and gained only by
persevering struggles. He never forgot the debt he owed to Bristol, and
to the friends who helped him there; and he would have greatly rejoiced
to see the completion of his earliest and favourite work.
[Illustration: HUNGERFORD SUSPENSION BRIDGE
H. Adiard Sc.]
NOTE (p. 58).
_The Hungerford Suspension Bridge._
The suspension bridge which spanned the Thames at Charing Cross, on the
site of the present railway bridge, was designed and constructed by Mr.
Brunel between the years 1841 and 1845. It consisted of a centre span of
676 feet, and two side spans of 343 feet each. Being intended for foot
passengers only, its width was 14 feet. The versed sine, or deflection
of the middle of the catenary, was 50 feet. The two river piers, which
still exist up to the level of the railway, and form piers of the
present bridge, were of brickwork, with large footings at the bottom, so
as to distribute the pressure over a considerable area. The whole
structure was made hollow and as light as possible. From the level of
the footway the piers were carried up as ornamental campanile towers,
the weight of the chains being taken by four solid pillars of brickwork,
7 feet 3 inches square, forming the angles. Mr. Brunel introduced here
many of the arrangements he had designed for the Clifton bridge. In
order that the pressure from the chains might be always vertical on the
piers, the saddles rested on rollers working in oil, on the level
surface of a large cast-iron bed-plate. By this arrangement it was
rendered possible for the chains of the land spans to leave the tower at
a greater inclination than those of the middle span, so that the chains
were made shorter, and as they were at a lower level where they met the
abutment, there was less change in their direction at that point, and
consequently less thrust on the brickwork. Freedom of horizontal motion
was also secured, so that, in the case of unequal loading of the spans,
the chains might accommodate themselves to the strains, and move
horizontally until equilibrium was restored. At each of the land
abutments the chains passed down over a fixed saddle, at an inclination,
to anchorages placed at the bottom of the abutment. The brickwork under
the fixed saddle was so disposed as to resist directly the thrust
resulting from the change of direction between the main chains and the
anchor chains. To resist any movement of the abutments, the piles on
which they rested were driven obliquely, with their heads inclined from
the river. These piles were very numerous, the abutments spreading out
so as to cover a large area at the foundations. Nearly all the spaces
between the longitudinal, cross, and outside walls were filled with
concrete, in order that the abutments might be as massive as possible.
The details of the brickwork in the piers and abutments showed Mr.
Brunel’s skill in the economical employment of this material. The chains
were constructed so that the sectional area was proportional to the
strain; the total area at the centre was 296 square inches, while near
the piers it was 312 square inches. There were four chains, two on each
side of the bridge, placed one above the other, and consisting each
alternately of ten and eleven links. The links were 24 feet long and 7
inches in depth, the thickness varying so as to give the requisite
sectional area.
The relative diameter of pin, and proper form of the ends of the link,
were subjects of much consideration, and many experiments were made in
order to determine these points. The fact that two specimens of iron,
apparently identical in every respect, sometimes exhibit considerable
difference in their breaking weights, shows that an average of a great
number of experiments is required in order to test satisfactorily any
proposed refinements of construction. Mr. Brunel, however, convinced
himself by experiment that he had practically arrived at such a form of
link and diameter of pin that the chain would have no tendency to break
at one point rather than another. The links were forged with shoulders
near the eyes, in order that by means of clamps the pin could be taken
out and the links disengaged, if necessary.
The efficient action of the rollers was demonstrated shortly after the
completion of the bridge. On the occasion of the opening of the Corn
Exchange by Prince Albert, one of the land spans was crowded with
people, while the centre span was nearly empty. In consequence of this
the land chains became depressed considerably below their normal
position; and the saddles on the top of the tower nearest to the loaded
span moved horizontally on the rollers to the extent of 3 inches; and,
when the crowd had dispersed, they returned to their original position.
Many years after the completion of the bridge a proposal was made to
widen it for carriage traffic; but this was not carried out, and
eventually the superstructure was removed, to make way for the bridge of
the Charing Cross Railway. As the Hungerford Suspension Bridge has
ceased to exist, an engraving has been given of it (Plate II. p. 59), in
order that some record of its appearance may remain.
CHAPTER III.
_EARLY HISTORY OF THE GREAT WESTERN RAILWAY._
A.D. 1833--1835. ÆTATIS 27--30.
SKETCH OF THE HISTORY OF RAILWAYS IN ENGLAND PRIOR TO 1833--THE
STOCKTON AND DARLINGTON--THE LIVERPOOL AND MANCHESTER--THE LONDON
AND BIRMINGHAM--PROPOSED RAILWAY BETWEEN LONDON AND BRISTOL--MR.
BRUNEL APPOINTED ENGINEER, MARCH 7, 1833--SURVEY OF THE
LINE--UNSUCCESSFUL APPLICATION TO PARLIAMENT IN 1834--SUCCESSFUL
APPLICATION IN 1835--REMINISCENCES OF MR. BRUNEL,
1833-1835--EXTRACT FROM MR. BRUNEL’S DIARY, WRITTEN AT THE CLOSE OF
1835.
Before entering upon the history of the Great Western and the other
railways of which Mr. Brunel was the engineer, it may be useful to give
a brief sketch of the development of the railway system, previous to the
period when he first became engaged in works of this description.
The first railway in England designed for the conveyance of general
merchandise and passengers, was the Stockton and Darlington. An Act of
Parliament authorising the construction of this line was passed in 1821.
In 1823, a further Act was obtained, in which a clause was inserted, at
the request of Mr. George Stephenson, then the engineer of the company,
taking power to work the railway by locomotive engines, and to employ
them for the haulage of passengers. This railway, which consisted of a
single line with four sidings in the mile, was opened for traffic on
September 27, 1825. Its success led at once to the promotion of similar
works in other parts of the country.
Next in order must be noticed the celebrated railway between Liverpool
and Manchester. A project for constructing a line of railway between
these important towns was discussed as early as the year 1822; but a
company for carrying it out was not formed till two years later. In
1825, the directors applied to Parliament for an Act; and after a long
contest before a committee of the House of Commons, the preamble
approving of the construction of the railway was carried by a majority
of one. The Bill was, however, withdrawn, as the first two clauses
empowering the company to make the line, and to acquire land for that
purpose, were lost.[38] In the following year the Act was obtained, and
the works were commenced under the direction of Mr. George Stephenson.
The line was opened for traffic on September 15, 1830.
In 1824, Mr. George Stephenson wrote a report on a proposed line
connecting Liverpool and Birmingham. Surveys were made, and plans
deposited; but the Bill was thrown out on standing orders. A similar
fate attended the introduction of a Bill in 1826. In 1830, a new line
was surveyed by Mr. Joseph Locke and Mr. Rastrick, under the direction
of Mr. George Stephenson. The Act was obtained in 1833, and the railway,
which was called the Grand Junction, and is now a part of the London and
North-Western system, was constructed by Mr. Locke.[39]
In 1830, surveys were commenced by Mr. Robert Stephenson for a line
between London and Birmingham, and a Bill was introduced into Parliament
in 1832. The Liverpool and Manchester Railway had now been opened for
some time, and the promoters of the Birmingham line had the advantage of
being able to give in evidence the results of the working of the earlier
undertaking. Those results, it is said, were such as to startle most of
those who heard them. It was shown that a speed had been attained double
that of the fastest stage-coach, that the cost of travelling had been
diminished by one half, and that out of 700,000 persons carried since
the opening of the railway, only one had met with a fatal accident. The
amount of travelling between Liverpool and Manchester had increased
four-fold, and the value of the shares of the railway had risen one
hundred per cent. Similar evidence was given as to the results of the
working of the Stockton and Darlington Railway, and the promoters
endeavoured to prove that advantages at least as great would arise from
the construction of a railway between Birmingham and London. They were
successful in the House of Commons; but, they failed to convince the
Upper House that the benefits which such a railway would confer on the
country traversed by it were sufficient to entitle its promoters to
receive for it the sanction of the legislature. The Bill was again
introduced in the following session (1833); and, strange to relate, it
passed both Houses almost without opposition.[40]
* * * * *
Meanwhile, the principal merchants of Bristol, who had in 1825 made an
attempt to get up a railway company, were urged forward, both by the
inadequacy of their communications with the metropolis, and by the
success of the Liverpool and Manchester Railway, to make another effort.
In the autumn of 1832 a committee was formed of members of the
corporation, and other public bodies of the city of Bristol, to carry
out the project of a railway to London.
The first step taken by the committee was the appointment of an engineer
to make the preliminary surveys, and to prepare an estimate of the cost
of the undertaking.
Among the candidates for the post was Mr. Brunel. He was well known in
Bristol as the engineer of the Clifton Suspension Bridge, and of the
works for the improvement of the Floating Harbour. He had made many
friends among the leading citizens, and they used their best exertions
to procure his election; but there were several other candidates in the
field who had great local interest, and the contest was a close one.
While the issue was yet undecided, an unexpected difficulty arose. Some
members of the committee resolved to select their engineer by means of a
competition among the candidates, as to which of them would provide the
lowest estimate. Upon this being announced, Mr. Brunel declared that he
must withdraw his name, as he could not consent to become a party to so
objectionable a proceeding. ‘You are holding out,’ he wrote to the
committee, ‘a premium to the man who will make you the most flattering
promises. It is quite obvious that the man who has either least
reputation at stake, or who has most to gain by temporary success, and
least to lose by the consequences of disappointment, must be the winner
in such a race.’ Happily, this plan was abandoned; Mr. Brunel obtained a
majority of votes, and was appointed engineer on March 7, 1833.
He commenced the survey without delay; and in addition to his strictly
professional duties, he assisted in forming a committee in London, and
took a leading part in the consultations which were held upon various
important matters connected with the general interests of the
undertaking.
A hasty survey of the country between London and Bristol occupied him
till the middle of June; and as soon as it was completed, and the course
of the line settled on, preparations were made for placing the scheme
before the public.
The first public meeting was held on July 30, 1833. Mr. Brunel thus
refers to it in his diary:--‘Got through it very tolerably, which I
consider great things. I hate public meetings: it is playing with a
tiger, and all you can hope is, that you may not get scratched, or
worse.’ The result, however, seems to have been successful, and in a
month’s time a company was formally constituted, and the parliamentary
survey commenced.
Mr. Brunel organised a staff of assistants, at that time rather a
difficult task, and set them to work on various parts of the line. His
own duty of superintendence severely taxed his great powers of work. He
spent several weeks travelling from place to place by night, and riding
about the country by day, directing his assistants, and endeavouring,
very frequently without success, to conciliate the landowners on whose
property he proposed to trespass.
His diary of this date shows that when he halted at an inn for the
night, but little time was spent in rest, and that often he sat up
writing letters and reports until it was almost time for his horse to
come round to take him on the day’s work. ‘Between ourselves,’ he wrote
to Mr. Hammond, his assistant, ‘it is harder work than I like. I am
rarely much under twenty hours a day at it.’
A great portion of this labour was for the time thrown away, for as
November 30 drew near, it became evident that subscriptions were not
coming in to the extent which would enable the directors to lodge a Bill
for the whole line in the session of 1834.
The directors therefore determined to apply to Parliament for powers to
make a railway from London to Reading, and from Bath to Bristol, ‘as a
means of facilitating the ultimate establishment of a railway between
London and Bristol;’ postponing till a future session their application
for an Act to enable them to complete the undertaking by making the line
from Reading to Bath.
The Bill was introduced into the House of Commons, and on March 10, Lord
Granville Somerset moved that it be read a second time. This motion was
seconded by the Earl of Kerry, and supported by several influential
members, amongst whom were Mr. Labouchere (the late Lord Taunton) and
Mr. Daniel O’Connell.
The second reading was carried by a majority of ninety in a House of 274
members.
The Bill was then referred to a committee which met on April 16, Lord
Granville Somerset being in the chair. Evidence was called to prove the
advantages of the railway to the agricultural and trading community of
the country through which it would pass, even if only the two proposed
divisions of the line were constructed.
The traffic in merchandise between Bristol and London was at this time
principally carried on by means of water carriage, consisting, first of
the river Avon navigation from Bristol to Bath, next of the Kennet and
Avon Canal from Bath to Reading, and lastly of the river Thames from
Reading to London. The evidence went to show that the distance between
London and Reading, which by railway would be thirty-six miles, amounted
by the river to nearly eighty; that the delays and impediments arising
from drought, flood, and frosts on the rivers, were such as sometimes to
detain barges for several weeks; and that so great were the consequent
uncertainties and inconveniences of this navigation, that goods which
came as far as Reading by the canal, were frequently sent thence to
London by road, although at a great increase of expense. Even under the
most advantageous circumstances, goods could not be conveyed from
Reading to London in less than three days, or in less than a day by the
river Avon from Bath to Bristol. It was therefore contended, that to
form a railway which should supersede, or at all events come in aid of,
the worst portions of the navigation between London and Bristol, would
be an important public benefit.[41] The various advantages of the
measure were most fully discussed in an investigation which lasted
during fifty-seven days. Against the Bill was arrayed every class of
opponent that a private Bill could possibly encounter. Those interested
in the canals, rivers, and stage-coaches, opposed it from the fear of
competition; the inhabitants of Windsor opposed it, because the railway
did not run so near to the town as they wished; the corporation of
Maidenhead opposed it, because they thought that all the traffic which
paid toll on their bridge over the Thames would be diverted to the
railway; landowners and farmers near town opposed it, because they
feared it would bring produce to London from a distance, as cheap as
that supplied by themselves.
There was another very formidable class of opponents to the Bill,
consisting of landed proprietors and owners of houses in the immediate
neighbourhood of London.
Many engineers were called by these several opponents, to show that a
more advantageous line of railway might have been selected; but, upon
sifting the merits of the various new lines proposed, it became apparent
that the one chosen by Mr. Brunel was the best. Indeed, although some
trifling deviations of his line were suggested, the opposing engineers
admitted that in all essential features the railway had been most
skilfully laid out. It was generally agreed that the line through the
valley of the Thames, and thence in a direction north of the Marlborough
Downs, was the only proper course for a railway between Bristol and
London, as the levels were much better, and communication could be made
with much greater ease with the northern and South Wales districts, than
if the route to the south of the Marlborough Downs had been selected.
The plans proposed for entering London raised great opposition. In this
respect public feeling has greatly changed, for now no railway is
thought complete which has not a terminus in the heart of London; and it
is considered an advantage for houses to be within easy reach of a
railway station; but in 1834 such a neighbour was looked upon with
horror and dismay--a nuisance to be, if possible, absolutely prohibited.
When Mr. Brunel commenced the survey for the London terminus, he had
some idea of bringing the railway in on the south side of the Thames;
but this was abandoned, as it was found to involve very heavy works, and
the line proposed in the first Bill was made to terminate on the north
side of the river at Vauxhall Bridge. It was to have been carried on a
viaduct 24 feet high, with a parapet 6 feet 6 inches high, to prevent
the passengers looking into the windows of the neighbouring houses.
The owners of the land through which this part of the line would pass
were influential members of the Upper House, and therefore the directors
thought it useless to brave their opposition; accordingly, on the
thirteenth day of the hearing, they abandoned the last two miles of the
viaduct, and proposed to stop at the ‘Hoop and Toy,’ a public-house
near the site of the South Kensington Station of the Metropolitan
Railway.
But although the opposition of some of the landowners was conciliated by
this concession, that portion of the line through Brompton which had not
been abandoned was attacked with unabated energy. The residents in
Brompton opposed the Bill from the apprehension that the railway would
interfere with their quiet and seclusion; Brompton being at that time
considered, at any rate by one of the counsel for the opposition, ‘the
most famous of any place in the neighbourhood of London for the
salubrity of its air, and calculated for retired residences.’ They could
not, indeed, be blamed for indulging in these apprehensions, if they
really believed in their counsel’s statement that ‘streams of fire would
proceed from the locomotive engines.’
Others objected to the viaduct itself as being an undertaking of so
colossal a nature as hardly to be practicable; and the supposed increase
of traffic and consequent obstruction in Piccadilly and other leading
thoroughfares brought down upon the promoters the opposition of the
Commissioners of Metropolitan Roads.
All these objections were made the ground of much argument in committee,
and doubtless had great influence over the minds of those who voted
against the Bill.
The engineering evidence occupied, as might be expected, the greater
part of the forty-two days during which witnesses were examined before
the committee, and of these forty-two days no less than eleven were
taken up by the cross-examination of Mr. Brunel. So protracted a
cross-examination has probably never been heard in any court or
committee-room. One of those present thus describes it:--
‘The committee-room was crowded with landowners and others interested
in the success or defeat of the Bill, and eager to hear Brunel’s
evidence. His knowledge of the country surveyed by him was marvellously
great, and the explanations he gave of his plans, and the answers he
returned to questions suggested by Dr. Lardner, showed a profound
acquaintance with the principles of mechanics. He was rapid in thought,
clear in his language, and never said too much, or lost his presence of
mind. I do not remember ever having enjoyed so great an intellectual
treat as that of listening to Brunel’s examination, and I was told at
the time that George Stephenson and many others were much struck by the
ability and knowledge shown by him.’
In his evidence, Mr. George Stephenson stated that he did not know any
existing line so good as that proposed by Mr. Brunel. ‘I can imagine (he
said) a better line, but I do not know of one so good.’[42]
At length, on the fifty-fourth day of the sittings of the committee, Mr.
Harrison, K.C., rose to reply on behalf of the promoters, and on the
conclusion of his address the Bill was passed.
In the House of Lords the second reading was moved by Lord Wharncliffe.
It was opposed, and on a division being taken, the motion was lost by a
majority of seventeen (30 content and 47 non-content). The Bill was
therefore thrown out.
The directors, undaunted by their defeat, lost no time in making
preparations for bringing a Bill before Parliament in the session of
1835, with such improvements as the experience of the past campaign
suggested to them. Taking into consideration the various grounds on
which opposition had been raised to the plans they had proposed for
entering London through the Brompton district, they opened negotiations
with the London and Birmingham Railway Company, and arrangements were
concluded by which the traffic of the Great Western Railway was to be
carried upon the London and Birmingham line for the first four miles out
of London, the junction being made a little to the west of the Kensal
Green Cemetery.
They had also during the autumn raised money enough to enable them to
apply to Parliament for powers to construct the whole of the line from
London to Bristol. They thus escaped all the sarcastic observations
which had been made upon the scheme of 1834, of which it had been said,
that it would be a head and a tail without a body, and neither ‘Great’
nor ‘Western,’ nor even a ‘railway’ at all, but ‘a gross deception, a
trick, and a fraud upon the public, in name, in title, and in
substance!’
On March 9, the earliest day allowed by the standing orders, the Bill
was read a second time and committed. A division being taken on the
motion for committal, there appeared in favour of the motion 160, and
against it none but the tellers.
Shortly after its first meeting, the committee, of which Mr. Charles
Russell, then member for Reading, was chairman, came to the resolution
that, inasmuch as the evidence given in the previous year as to the
public advantages of a Bristol railway had been referred to them by
order of the House, they needed no further evidence on that subject.
Counsel were therefore directed to confine their case as much as
possible to the merits of the line proposed.
Evidence was called by the opponents chiefly with a view to show the
advantages of a proposed line from Basing to Bath, and the inexpediency
of granting an entirely new line of 115 miles in length to the Great
Western Railway Company, which involved the construction of a ‘monstrous
and extraordinary,’ ‘most dangerous and impracticable, tunnel’ at Box,
and this, when 44 miles of railway in a western direction--viz. as far
as Basingstoke, had already been sanctioned by the legislature in the
Southampton Railway Act, passed in the previous session. The promoters
of the Bill contended that the levels of the Basing and Bath line were
not so good as those proposed for their own, and that the Great Western
Railway would approach almost every town of importance situated on the
proposed Basing and Bath line, by means of short branches; whilst at the
same time it presented the great advantage of being capable of easy
extension to Gloucester and Wales, and to Oxford, an object wholly
unattainable by the other line. In reply to these assertions, the
opponents maintained that although the levels of the Basing and Bath
Railway presented greater inclinations than those of the Great Western,
yet that they were so balanced as that the rises and falls compensated
one for another, so as to render the line practically level. The
enunciation of this theory called forth a remark by the chairman that
according to this principle the Highlands of Scotland would be as good
as any other place for the construction of a railway.
The preamble was voted proved, and the Bill passed the House of Commons
without further opposition, and on May 27 was read a first time in the
Lords. On June 10, the second reading was carried after a sharp debate,
the numbers being 46 contents, and 34 non-contents.
Lord Wharncliffe was chairman of the committee.[43] The proceedings
began by an opposition on the standing orders, which, after much
skirmishing, were voted to have been complied with. The promoters,
however, judged from the nature of the first day’s proceedings, that
they had to expect a contest of no inconsiderable duration; and the
result proved their anticipations to have been correct. For forty days
the battle was fought with a degree of earnestness and vigour on both
sides, almost unequalled in any similar proceedings.
The committee soon came to the same decision as the House of Commons,
that, with regard to the advisability of a Bristol railway, they were
satisfied, and needed no further evidence. The case became then one of
mere comparison between the relative merits of the two lines proposed.
The case in support of the Bill occupied eighteen days, and was closed
with a speech by the Hon. John Talbot.
Mr. Serjeant Merewether, whom the opponents had chosen as their leader
in the House of Lords, was then heard on their behalf, and occupied no
less than four days in the delivery of his speech, in which certainly no
argument that ingenuity could devise was omitted to strengthen his case.
There was hardly any conceivable injury which, according to the learned
serjeant’s notions, the Great Western Railway would not inflict. It was
said that the Thames would be choked up for want of traffic, the
drainage of the country destroyed, and Windsor Castle left unsupplied
with water. As for Eton College it would be absolutely and entirely
ruined: London would pour forth the most abandoned of its inhabitants to
come down by the railway and pollute the minds of the scholars, whilst
the boys themselves would take advantage of the short interval of their
play hours to run up to town, mix in all the dissipation of London life,
and return before their absence could be discovered. Moreover, while the
beauty of the country and the retirement of private dwellings would be
destroyed, the interests of the public would be far more effectually
served by the adoption of the Basing and Bath line, and a line from the
London and Birmingham Railway to Gloucester. This was in fact the point
at issue, and on this the result of the contest depended. The promoters
of the Bill had called, in support of their line, in addition to Mr.
Brunel, who being engineer to the company might be considered an
interested witness, Mr. Locke, Mr. Palmer, Mr. Price, Mr. George
Stephenson, and Mr. Vignoles. They expressed their unqualified
approbation of the line chosen by Mr. Brunel, and of the estimates he
had prepared.
The preamble was proved, and after an unsuccessful opposition the Bill
was read a third time, on August 27. The Royal Assent was given on the
last day of that month.[44]
* * * * *
During this contest Mr. Brunel made among his fellow-labourers many deep
and lasting friendships. One of the most intimate of these friends, Mr.
St. George Burke, Q.C., has, in compliance with a request made to him,
furnished the following reminiscences of his intercourse with Mr.
Brunel during the progress of the Bill through Parliament.
March 9, 1869.
‘My dear Isambard,--You wish me to supply you with reminiscences of
my old associations with your father, in order that, in your
biography of him, you may present a true picture of those features
of his character which so endeared him to his most intimate
friends.
‘For many years it was my good fortune to enjoy his friendship, and
many of the pleasantest hours of my life were due to it.
‘For a period of nearly three years, viz. during the contest for
the Great Western Railway Bill, I think that seldom a day passed
without our meeting, whether for purposes of business or pleasure,
both of which his buoyant spirits enabled him to combine in a
manner which I have seldom seen equalled.
‘It would be wearisome to detail the many incidents which occurred
illustrative of the singularly facile manner in which, in the midst
of the heaviest and most responsible labours, he could enter into
the most boyish pranks and fun, without in the least distracting
his attention from the matter of business in which he was engaged;
but all who knew him as I did could bear testimony to this
characteristic of his disposition.
‘I believe that a more joyous nature, combined with the highest
intellectual faculties, was never created, and I love to think of
him in the character of the ever gay and kind-hearted friend of my
early years, rather than in the more serious professional aspect
under which your pages will, no doubt, rightly depict him.
‘In 1833 your father and I occupied chambers facing each other in
Parliament Street, and as my duties involved the superintendence,
as Parliamentary agent, of the compliance with all the Standing
Orders of Parliament, and very frequent interviews and negotiations
with the landowners on the line, we were of necessity constantly
thrown together. To facilitate our intercourse, it occurred to your
father to carry a string across Parliament Street, from his
chambers to mine, to be there connected with a bell, by which he
could either call me to the window to receive his telegraphic
signals, or, more frequently, to wake me up in the morning when we
had occasion to go into the country together, which, it is needless
to observe, was of frequent occurrence; and great was the
astonishment of the neighbours at this device, the object of which
they were unable to comprehend.
‘I believe that at that time he scarcely ever went to bed, though I
never remember to have seen him tired or out of spirits. He was a
very constant smoker, and would take his nap in an arm-chair, very
frequently with a cigar in his mouth; and if we were to start out
of town at five or six o’clock in the morning, it was his frequent
practice to rouse me out of bed about three, by means of the bell,
when I would invariably find him up and dressed, and in great glee
at the fun of having curtailed my slumbers by two or three hours
more than necessary.
‘No one would have supposed that during the night he had been
poring over plans and estimates, and engrossed in serious labours,
which to most men would have proved destructive of their energies
during the following day; but I never saw him otherwise than full
of gaiety, and apparently as ready for work as though he had been
sleeping through the night.
‘In those days we had not the advantage of railways, and were
obliged to adopt the slower, though perhaps not less agreeable,
mode of travelling with post-horses. Your father had a britzska,
so arranged as to carry his plans and engineering instruments,
besides some creature comforts, never forgetting the inevitable
cigar-case among them; and we would start by daybreak, or sometimes
earlier, on our country excursions, which still live in my
remembrance as some of the pleasantest I have ever enjoyed; though
I think I may safely say that, pleasurable as they were, we never
lost sight of the business in which we were engaged, and for which
our excursions were undertaken.
‘I have never known a man who, possessing courage which to many
would appear almost like rashness, was less disposed to trust to
chance or to throw away any opportunity of attaining his object
than was your father. I doubt not that this quality will be fully
exemplified in the details which you will have received of his
engineering experiments; but I speak of him also in the character
of a diplomatist, in which he was as wary and cautious as any man I
ever knew.
‘We canvassed many landowners together, and I had plenty of
opportunities of judging of his skill and caution in our
discussions with them, though we had many a good laugh afterwards
at the arguments which had been addressed to us as to the inutility
and impolicy of the scheme in which we were engaged, and the utter
ruin it would be sure to entail on its promoters, as well as on the
country affected by it.
‘I frequently accompanied him to the west of England, and into
Gloucestershire and South Wales, when public meetings were held in
support of the measures in which he was engaged, and I had occasion
to observe the enormous popularity which he everywhere enjoyed. The
moment he rose to address a meeting he was received with loud
cheers, and he never failed to elicit applause at the end of his
address, which was distinguished as much by simplicity of language
and modesty of pretension as by accurate knowledge of his subject.
Yours very truly,
ST. GEORGE BURKE.
Isambard Brunel, Esq.’
The following is an extract from Mr. Brunel’s diary, written at the end
of the year 1835:--
53 Parliament Street, December 26.
What a blank in my journal [_the last entry is dated January
1834_], and during the most eventful part of my life. When last I
wrote in this book I was just emerging from obscurity. I had been
toiling most unprofitably at numerous things, unprofitably, at
least, at the moment. The railway was certainly being thought of,
but still very uncertain. What a change. The railway now is in
progress. I am thus engineer to the finest work in England. A
handsome salary, on excellent terms with my directors, and all
going smoothly. But what a fight we have had, and how near defeat,
and what a ruinous defeat it would have been. It is like looking
back upon a fearful pass; but we have succeeded.
And it is not this alone, but everything I have been engaged in has
been successful. Clifton bridge--my first child, my darling, is
actually going on: recommenced work last Monday--glorious!! [_Here
follows a list of the undertakings on which he was then engaged._]
I think this forms a pretty list of real sound professional work,
unsought for on my part, that is, given to me fairly by the
respective parties--all, except the Wear Docks, resulting from the
Clifton bridge, which I fought hard for, and gained only by
persevering struggles.... And this at the age of twenty-nine. I
really can hardly believe it, when I think of it. I am just leaving
53 Parliament Street, where I may say I have made my fortune, or,
rather, the foundation of it, and I have taken 18 Duke Street.
CHAPTER IV.
_RAILWAY WORKS._
A.D. 1835--1859. ÆTATIS 30--54.
CONSTRUCTION OF THE GREAT WESTERN RAILWAY--THE BOX TUNNEL--THE BATH
AND BRISTOL STATIONS--THE PADDINGTON STATION--THE GREAT WESTERN
HOTEL--BRANCHES AND EXTENSIONS OF THE GREAT WESTERN RAILWAY--THE
BRISTOL AND EXETER RAILWAY--RAILWAYS IN DEVONSHIRE AND
CORNWALL--RAILWAYS TO BASINGSTOKE, TO WEYMOUTH, AND TO
SALISBURY--IN SOUTH WALES--IN IRELAND--IN ITALY--IN
INDIA--SUPERVISION OF WORKS--MR. BRUNEL’S ENGINEERING STAFF--HIS
REPUTATION AS A WITNESS--REMINISCENCES OF MR. BRUNEL, 1835-1838.
In the extract from Mr. Brunel’s diary given at the close of the last
chapter he refers to the successful issue of the contest for the Great
Western Railway Act as a very important event in his life.
As the result proved, he did not take too hopeful a view of his future
prospects; for from that time to his death he was fully employed as the
engineer of railways which, in number and importance, were not inferior
to those of any of his contemporaries. Of the main lines he constructed,
one extends uninterruptedly from London to the Land’s End, and another
to the extremity of South Wales, at Milford Haven, 285 miles from
Paddington.
* * * * *
It would be impossible to describe in detail all the engineering works
which are to be found on Mr. Brunel’s railways, the aggregate length of
which is upwards of 1,200 miles; but in this chapter it is proposed to
give a brief sketch of the lines he constructed, omitting all that can
be more properly inserted in the three chapters which follow, relating
to the broad gauge, to the Atmospheric System, and to the bridges and
viaducts.
* * * * *
The Great Western Railway was opened to Maidenhead, a distance of nearly
twenty-three miles, in June 1838, and to Twyford, eight miles farther
on, in July 1839. A description of the Wharncliffe Viaduct at Hanwell
will be found at p. 172, and of the Maidenhead bridge at p. 173.
The line from Twyford to Reading was opened in March 1840, and from
Reading to Chippenham by May 1841. Meanwhile the portion from Bristol to
Bath had been opened in August 1840. The last division, namely, that
from Chippenham to Bath, containing the Box Tunnel, was opened on June
30, 1841; and the railway was completed throughout its whole length.
* * * * *
A considerable part of the history of the Great Western Railway is
connected with the adoption on it of the broad, or 7-foot gauge, and
will be dealt with in the next chapter, in which is also given some
account of the longitudinal system of permanent way.
The bridges are described in Chapter VII.; but some of the other works
may be noticed here.
In laying out the line, Mr. Brunel endeavoured to make it as straight
and as level as possible throughout, and to concentrate those changes of
level, which could not be avoided, into short inclines, to be worked, if
necessary, by auxiliary power.
Accordingly the line is thus divided:--
Miles Yards
Level, or with an inclination not exceeding
4 feet in the mile 67 88
Above 4 feet, and not exceeding 8 feet in
the mile 47 110
Steep inclines 3 1210
The steep inclines are two in number, of a gradient of 1 in 100, or
about 53 feet in a mile, and descend towards the Bristol end of the
line.
The Wootton Basset incline, 85½ miles from London, is 1 mile 550 yards
long.
The second incline is at Box, 99 miles from London, and is 2 miles 660
yards in length. An assistant engine is still occasionally used to work
heavy trains at this point.
On this incline the line passes through the Box Tunnel. This tunnel is
the first out of London, and could only have been dispensed with by
taking a circuitous route several miles longer than that adopted by Mr.
Brunel.
The tunnel is 1⅞ mile in length, and is ventilated by six shafts.
They are 30 feet in diameter, and from 70 to 300 feet deep.
The Box Tunnel had been the subject of much criticism before the works
were commenced; and during its actual construction it did not escape the
unfavourable notice of those who were ignorant of the difficulties which
presented themselves, and the means which had been taken to overcome
them. Indeed, for some time after the opening of the line, there were
travellers who used to avoid the terrors of the tunnel by posting along
the turnpike road in that part of their journey.
Mr. Brunel never troubled himself about the ordinary gossip which is
always circulated concerning any remarkable work; but matters assumed a
different aspect when, a year after the completion of the tunnel, doubts
were expressed as to its safety by an eminent geologist, at a meeting of
the Institution of Civil Engineers. Mr. Brunel, who was on terms of
friendly intercourse with the speaker, addressed to him the following
letter:--
June 21, 1842.
I assure you, my dear Sir, that when my attention had been drawn to
the statements reported to have been made by you on this subject,
I refrained as far as possible from expressing any opinion. I
thought it my duty to read the notes taken, but I never said that I
thought your statements were correct. Indeed, I had hoped to have
avoided the necessity of making any observations upon these
statements; but as a letter to Mr. Saunders on such a subject is
almost the same thing as if it were addressed to myself, and as it
was shown to me, it would not be candid towards you if I now
refrained from saying, that the opinions you are reported to have
expressed with respect to the Box Tunnel are by no means considered
correct, either by myself or by those others who, from being
intimately acquainted with the rock as it was really found, and the
works as they were really executed, are capable of judging.
In the notes shown to me the observations alluding to this work in
particular, as an illustration of the views you were explaining,
appear to have been curtailed, and the allusions rendered somewhat
less direct; but still the inference unavoidably to be drawn from
them is, that the back joints, as we call them, and other defects
which exist originally, or which show themselves after a time, in
this rock, are not well known, and tolerably well understood and
guarded against, by practical engineers, and even by our workmen.
In this opinion I assure you you are mistaken. Ignorant as I may
probably be myself of the science of geology, I cannot have been
engaged for several years in making very extensive excavations,
probably the largest hitherto made, in this particular rock, having
also the opportunity of examining very old and large quarries in
the same rock and close to the line, having among my assistants men
not meanly acquainted with this particular branch of geology, and
surrounded by workmen of considerable experience, I cannot have
gone through such a study without acquiring a very intimate and
practical knowledge of the structure and peculiarities of the
particular mass of rock which is now in question; and I will say
frankly what I feel upon this point, which is, that I ought now to
possess a more thorough and practical knowledge of this particular
rock and its defects, and the best mode of remedying them, than
even you yourself, with your immeasurably greater scientific
knowledge of rocks generally.
The opinion you are said to have expressed of there being great
danger of some serious accident occurring in the tunnel is, I am
firmly convinced, erroneous; at all events the reason given
convinces me that you have not become acquainted with the means
which have been taken by me to examine and to ascertain the
security of every part of the rock, to remove or to support with
masonry any part not so ascertained to be secure, or with the
precautions taken to prevent any such accidents as those you have
imagined. And notwithstanding the heavy responsibility which rests
upon me, from all which you gentlemen of science are, happily for
yourselves, so free, I feel that as regards the works of the Box
Tunnel everything necessary has been done to render them secure,
and that the doubts and fears you have so easily raised, but which
it might be more difficult again to set at rest, are entirely
unfounded.
In conclusion, I must observe that no man can be more sensible than
I am of the great advantage it would be to me as a civil engineer
to be better acquainted with geology, as well as with many other
branches of science, that I have endeavoured to inform myself on
the subject, and that I have not altogether thrown away the many
opportunities afforded me in my professional pursuits; but that if
from a conviction that you possessed information far more extensive
than mine, if from doubts of the sufficiency of my abilities or the
means I was likely to bring to bear upon the subject, if from a
fear of such consequences as you now anticipate, you had kindly, on
any one of the many occasions when I have had the pleasure of
meeting you, intimated that you had any suggestions to make to me,
I should have been anxious to have availed myself of your
assistance. But after the lapse of years, the first intimation I
have of such doubts is the very public expression of a very strong
opinion, which, if weight be attached to it, must tend to alarm the
public unnecessarily, and to injure the value of the property of
individuals who have embarked several millions in that property.
Between Chippenham and Bristol the nature of the building stone enabled
Mr. Brunel, at moderate cost, to make the bridges, tunnel fronts, and
stations ornamental features in the picturesque scenery through which
the railway passes.
He took great pleasure in finishing minutely the various designs, and
making them correct in their proportions and details. One tunnel front,
near Bristol, may be singled out for especial mention. During its
construction a part of the ground behind slipped away, and it became
unnecessary to complete the top of one of the side walls. It was
therefore left unfinished, and was planted with ivy so as to present the
appearance of a ruined gateway.
The roofs of the Bath and Bristol stations are of large span, and are
handsome architectural structures. They are each in the form of a Tudor
arch; the Bristol roof is 72 feet span, and the Bath roof 50 feet span.
The framing is an example of a peculiar form of construction, somewhat
analogous to that adopted in the large shipbuilding sheds in the
dockyards. There are no cross tie-rods, but each principal of the roof
is formed of two frameworks, like cranes, meeting in the middle of the
roof; the weight being carried on columns near the edge of the platform,
and the tail ends of the frames held down by the side walls. As the two
frames do not press against each other at their meeting point at the
ridge of the roof, there is no outward thrust. The side walls being on a
viaduct could not without difficulty have been made to resist a
horizontal thrust.
At the Bristol station Mr. Brunel introduced hydraulic machinery for
working lifts. By these the waggons were lowered to and raised up from
the goods shed, which was placed at the level of the ground, about 12
feet below the railway.
Although the works already described were completed in 1841, the
permanent terminus at Paddington was not commenced till the year 1849.
It was completed in 1854. Previously to that time a temporary station
had been used, the booking offices being under the arches of the
Bishop’s Road bridge.
As the level of the railway was lower than that of the surrounding land,
no exterior architectural effect could be produced; but Mr. Brunel took
this opportunity to carry out his views as to the proper structural use
of metal in works of this description.
In the design of the ornamental details, he obtained the assistance of
Mr. (now Sir Matthew) Digby Wyatt.
The interior of the principal part of the station is 700 feet long and
238 feet wide, divided in its width by two rows of columns into three
spans of 68, 102, and 68 feet, and is crossed at two points by transepts
50 feet wide, which give space for large traversing frames. The roof is
very light, consisting of wrought-iron arched ribs, covered partly with
corrugated iron and partly with the Paxton glass roofing, which Mr.
Brunel here adopted to a considerable extent. The columns which carry
the roof are very strongly bolted down to large masses of concrete, to
enable them to resist sideways pressure.
This station may be considered to hold its own in comparison with the
gigantic structures which have since been built, as well as with older
stations. The appearance of size it presents is due far more to the
proportions of the design than to actual largeness of dimension. The
spans of the roof give a very convenient subdivision for a large
terminal station, dispensing with numerous supporting columns and at the
same time avoiding heavy and expensive trusses. The graceful forms of
the Paddington station, the absence of incongruous ornament and useless
buildings, may be appealed to as a striking instance of Mr. Brunel’s
taste in architecture and of his practice of combining beauty of design
with economy of construction.
The goods station was erected at about the same time as the passenger
station, and is remarkable for the completeness of its arrangements, and
for the great use made of hydraulic machinery. This is also applied in
the passenger station.[45]
In connection with the Paddington station mention may be made of the
Great Western Hotel, which was built at the extremity of the land
belonging to the railway company.
When, in 1854, no tenant could be found for it, a few of the
shareholders of the Great Western Railway, being unwilling that the
building should remain empty and be a loss to the proprietors, formed
themselves into a company to lease and work the hotel. Mr. Brunel became
a Director, and shortly afterwards (in December 1855) the chairman. He
occupied this post till his death, by which time the hotel had become
very prosperous. He found attendance at the meetings of the Directors
and the supervision of the management of the hotel a very agreeable
relaxation from the more important duties which took him to Paddington.
* * * * *
The branches and extensions of the Great Western Railway, as far as
their history affected the general interests of the company, are
referred to in the chapter on the broad gauge. Branches were opened to
Oxford in 1844, to Windsor in 1849, to Wycombe in 1854, to Uxbridge in
1856, to Henley in 1857, and to Brentford in July 1859.
* * * * *
The Bristol and Exeter Railway is a continuation of the Great Western
Railway, and was opened to Exeter in 1844. The two portions of it, from
Bristol to Taunton, and from Taunton to Exeter, are in marked contrast
to each other. The former part of the line is almost level, and has very
easy curves. Between Taunton and Exeter it passes over the high ground
on the borders of Devonshire, with the Whiteball Tunnel at the summit,
⅝ mile in length. On this part of the line there are long gradients of
from 1 in 80 to 1 in 120. Mr. Brunel resigned the position of engineer
in 1846, in consequence of differences having arisen between the Bristol
and Exeter and the Great Western Companies, which, in Mr. Brunel’s
opinion, made it impossible for him to continue engineer to both
railways.
The South Devon Railway, and the adoption on it of the Atmospheric
System, are described in Chapter VI. In connection with this line is the
important Torquay branch, and the railway in continuation of it to
Dartmouth. This was completed as far as Paignton during Mr. Brunel’s
lifetime.
The South Devon and Tavistock Railway branches off from the South Devon
Railway near Plymouth, and has several large viaducts.
On the Cornwall Railway from Plymouth to Truro, and the West Cornwall
Railway from Truro to Penzance, the most remarkable works are the
viaducts, and the Royal Albert Bridge.
In the case of the Cornwall Railway, it became necessary to reduce the
capital expenditure, even at the cost of increasing the charges for
maintenance. With this object the line was re-examined and modifications
introduced, principally by an increase in the extent of viaduct. These
lines pass through a very difficult country; involving the adoption of
steep gradients and sharp curves. Mr. Brunel, in a memorandum written in
1845, after having explained his reasons for considering that the
prejudicial effects of gradients and curves were commonly overrated,
gives the following opinion in reference to the proposed Cornwall
Railway:--
I must not be understood to argue against the advantage of straight
lines or large and easy curves, but I wish to show that where small
curves are unavoidable, they can in practice be so constructed as
not to be very prejudicial; and I consider that the character of
the country in Cornwall is such that no railway can be constructed
at any moderate expense without either sacrificing all
consideration for the interests of localities and the position of
the population to the mere choice of levels, or without steep
gradients and sharp curves.
The principal lines branching off from the Great Western, and since
incorporated with it, are, on the south, the Berks and Hants, from
Reading to Basingstoke and Hungerford; and the Wilts and Somerset, to
Weymouth and Salisbury. On the north-west is the Cheltenham and Great
Western Union Railway, from Swindon to Cheltenham and Gloucester. This
line passes through the Cotswold Hills at Sapperton by a tunnel 1⅜
mile in length. The Gloucester and Dean Forest Railway runs from
Gloucester to Grange Court, and thence to Ross and Hereford.
The South Wales Railway, which extends from Grange Court to Milford
Haven, contains a tunnel at Swansea ⅓ mile long, and some of Mr.
Brunel’s most important works, including the Chepstow bridge and several
other bridges of considerable size, and the viaducts at Landore and
Newport. There are also on this line four opening bridges across
navigable channels. The works at the termination of the line at Neyland,
in Milford Haven, are described in Chapter XIV. Mr. Brunel considered
that Milford Haven, with its excellent harbour, which can be entered at
all times of tide by the largest vessels, would probably become a great
port for ocean steamers, and especially for the ‘Great Eastern’ and
ships of her class.
There are also in South Wales the following railways: the Taff Vale, the
Vale of Neath, the Llynvi Valley, and the South Wales Mineral. The Taff
Vale, a line from Cardiff to Merthyr, was opened on the narrow gauge in
1841.[46] On this railway is the lofty masonry viaduct at Quaker’s Yard.
On the Vale of Neath Railway, from Neath to Aberdare and Merthyr, there
is a tunnel, near Merthyr, 1¼ mile long, and 650 feet below the summit
of the hill.
Full advantage is taken on this railway of the facilities which the
broad gauge offers for heavy traffic. The line has long steep gradients,
and the locomotives used on it, of the class known as tank engines, are
of great power. One of these gradients is 4½ miles long, with an
inclination of 1 in 50. Large quantities of coal are brought down by
this railway to the Swansea and Briton Ferry Docks. The coal of South
Wales is of a friable nature, and, in order to avoid the breakage
consequent on the ordinary mode of shipping coal, by tipping it down a
shoot, Mr. Brunel introduced on a large scale the use of trucks carrying
four iron boxes, each box about 4 feet 8 inches cube, and containing two
and a half tons of coal. At the docks machinery is provided by which
each box is lowered down into the hold of the ship, and the under side
being allowed to open, the coal is deposited at once on the bottom of
the vessel.
The Llynvi Valley Railway is a short line, leading from the South Wales
Railway at Bridgend into the coal and iron districts.
The South Wales Mineral Railway is another line of the same class. It
passes through a very heavy country, and has on it a self-acting incline
of 1 in 9, ¾ mile long, worked by a rope, and a tunnel ⅝ mile long,
and 470 feet below the surface.
In connection with the South Wales district is the Bristol and South
Wales Union Railway, a line running from Bristol to the banks of the
Severn, across which the traffic is carried by a steamer to a short
branch from the South Wales Railway on the other side. This railway had
been for a long time contemplated, and Mr. Brunel devoted much time to a
careful investigation of the Severn in order to determine the most
suitable point for the crossing. He decided that the best place would be
at what is known as the New Passage. The arrangements had to be made in
accordance with the requirements of the Admiralty. Trains run to the end
of timber piers extending into deep water, and there are staircases and
lifts leading to pontoons, alongside which a steamer can come at all
times of tide. The tide at this part of the Severn rises 46 feet.
The three railways last mentioned were not completed during Mr. Brunel’s
lifetime.
* * * * *
The Bristol and Gloucester Railway, on which is the tunnel at Wickwar,
¾ mile long, was opened in 1844, and passed into the hands of the
Midland Company in 1846.
* * * * *
The northern extensions of the Great Western Railway are the Oxford and
Rugby, constructed as far as Fenny Compton; the Birmingham and Oxford
Junction; and the Oxford, Worcester, and Wolverhampton Railways.
Mr. Brunel ceased to be engineer of the last-mentioned company in 1851,
and the works were completed by Mr. Fowler. The Oxford, Worcester, and
Wolverhampton line has since, under the title of the West Midland,
become a part of the Great Western Railway.
* * * * *
In Ireland Mr. Brunel was engineer of the line from Dublin to Wicklow,
round Bray Head, and of a line from Cork to Youghal.
* * * * *
He laid out two railways in Italy, the line from Florence to Pistoja,
and that across the Apennines from Genoa to Novi and Alessandria, in the
direction of Turin and Milan. He acted as engineer during the
construction of the former line; but the works of the latter were
carried out by the Sardinian Government.
* * * * *
One of the last of Mr. Brunel’s important railways was the Eastern
Bengal Railway, a line of about 100 miles in length, in a north-easterly
direction from Calcutta. He took a great interest in the work and
devoted much time to the special arrangements and designs, and to the
best way of crossing the Ganges and its branches in the future extension
of the railway; but no part of it was opened during his lifetime.
* * * * *
It was impossible for Mr. Brunel to look after all his works to the same
extent as he had done in the case of the Great Western Railway; and he
was compelled to spend a very considerable amount of time in attendance
on Committees of the Houses of Parliament on behalf of the railways to
which he was engineer. Mr. Brunel frequently regretted this, and
considered it a great evil that engineers were prevented by their duties
during the session from attending properly to the construction of their
works. He endeavoured as far as possible to superintend the execution of
his different undertakings. He availed himself of every opportunity of
examining them, and was acquainted throughout with all the designs which
were prepared. He would take advantage of two or three free days to go
down to the distant works in South Wales or in Cornwall, looking after
details, such as the pickling tanks for timber, and the masonry of the
viaducts.
He was fortunate in the selection of the members of his staff, and in
his organisation of it. He had a rare power of utilising the
capabilities of his different assistants; and although he had to deal
with a great variety of men, he managed that they should work in harmony
with him. From the complete personal supervision Mr. Brunel sought to
maintain over all his works, his assistants had not perhaps so many
opportunities of independent action as they might otherwise have
obtained, but they had, on the other hand, the advantage of constant
personal communication with their chief.
After the time when Mr. Brunel’s works became so numerous, and his time
so much occupied, that he could not exercise in person that general
supervision which he conceived to be necessary, he was ably assisted by
Mr. Robert Pearson Brereton, who, on the death of Mr. Hammond in 1847,
became the chief of his engineering staff.
Mr. Brunel rarely made any changes in the _personnel_ of his office. Mr.
Brereton had become one of his assistants in 1836; and his secretary,
the late Mr. Joseph Bennett, came to him in the same year.
* * * * *
The Great Western Railway retained its early place in his affections,
and among his most valued friends were members of the Board of
Directors, Mr. Saunders the Secretary, and other officers of the
company. When in the last year of his life he was obliged to go to Egypt
for his health, it was a matter of deep anxiety to him lest his absence
from England should cause any alteration in his relations with the
Company, and it was a source of great pleasure to him that no such
consequences followed.
* * * * *
Mr. Brunel’s position as confidential adviser of so large a number of
railway companies gave him frequent opportunities of acting as mediator
between contending parties; and his decisions were always received with
respect, for he was known to be scrupulously just.
Besides the more friendly task of reconciling opponents he had a large
practice as a referee under Acts of Parliament and orders of the
superior courts; and displayed in these matters great judicial
abilities.
In all the causes and parliamentary contests affecting the various
companies of which he was engineer, Mr. Brunel was a very important
member of the preliminary consultations, and during the proceedings
counsel relied with confidence on his suggestions.
* * * * *
One of the most arduous parts of his duty, as engineer of the Great
Western Railway Company, was connected with the conduct of the great
cases of Ranger and MacIntosh. To the former of these reference is made
in the letter printed below, at p. 478. The MacIntosh case, which was
commenced shortly after the opening of the line, was not concluded
before Mr. Brunel’s death. He was compelled to devote a considerable
portion of his time to it, even after his return home in the evening,
during the launch of the ‘Great Eastern.’
* * * * *
Mr. Brunel had a very high reputation as a witness. Mr. St. George
Burke, Q.C., has communicated a memorandum on this subject.
‘As a witness he could always be relied on as a perfect master of
the case he had to support, and he had the rare quality of
confining his answers to a simple reply to the questions put to
him, without appearing as an advocate. He was, however, extremely
particular as to the questions which should be put to him in his
examination in chief, and was therefore never satisfied to entrust
the preparation of his proof to the solicitor, without revising it
himself.
‘In his cross-examinations he was generally a match for the most
skilful counsel, and by the adroitness of his answers would often
do as much to advance his case as by his examination in chief.
‘He was almost as much of a diplomatist as an engineer, and knew
perfectly well how to handle a case in the witness-box so as to
leave no loophole for his opponents to take advantage of. At the
same time he was a perfectly honest witness, and while he avoided
saying more than was necessary for the advancement of the cause in
which he was engaged, he would have scorned to say or imply
anything by his evidence inconsistent with strict truth.
‘Although he had attained to great celebrity as a witness, the
committee room being crowded to hear him, he always declined to
engage in the very lucrative work of a professional witness. He
made a rule never to appear except on behalf of undertakings of
which he was the engineer, or with which his own companies were
interested. To help a friend, he occasionally but very rarely broke
through this resolve; but, whether he appeared in support of his
own plans or those of others, there were few, if any, professional
men whose evidence carried more weight than his did before
Parliamentary Committees.’
The following memorandum from Mr. George T. Clark, of Dowlais, formerly
one of Mr. Brunel’s assistants, contains his recollections of Mr. Brunel
during the construction of the Great Western Railway:--
‘I made your father’s acquaintance, rather characteristically, in
an unfinished tunnel of the Coal-pit Heath Railway; and when the
shaft in which we were suspended cracked and seemed about to give
way, I well remember the coolness with which he insisted upon
completing the observations he came to make. Shortly afterwards I
became, at his request, his assistant; and during the
parliamentary struggle of 1835, and the subsequent organisation of
the staff, and commencement of the works of the Great Western, I
saw him for many hours daily, both in his office and in the field,
travelled much with him, and joined him in the very moderate
recreation he allowed himself.
‘These two years, and the preceding year, 1834, were, I apprehend,
the turning points of his life. His vigour, both of body and mind,
were in their perfection. His powers were continually called forth
by the obstacles he had to overcome; and the result of his
examinations in the committee rooms placed him, in the opinion of
the members of the legislature, and of his own profession, in the
very first rank of that profession, both for talents and knowledge.
‘I wish I could convey to you even a tolerable idea of your father
as he was in those years, during which I knew him intimately, and
saw him often under circumstances of great difficulty.
‘He was then a young man, but in the school of the Thames Tunnel he
had acquired a close acquaintance with all kinds of masons’ and
carpenters’ work, the strength and cost of materials, bridge
building, and constructions under water, and with the working of
the steam engine as it then stood. It happened not unfrequently
that it was desirable to accept the tender of some contractor for
railway work whose prices upon certain items were too high, and
then it became the engineer’s business to go into the details and
convince the contractor of his error. On such occasions Brunel
would go step by step through the stages of the work, and it was
curious to see the surprise of the practical man as he found
himself corrected in his own special business by the engineer.
Thus, I remember his proving to an eminent brickmaker who had
tendered for the Chippenham contract that the bricks could be made
much cheaper than he supposed. He knew accurately how much coal
would burn so many bricks, what it would cost, what number of
bricks could be turned out, what would be the cost of housing the
men, what the cartage, and how many men it would require to
complete the work in the specified time. The contractor was
astonished; asked if Mr. Brunel had ever been in the brick trade,
and finally took and made money by the contract at the proposed
figure.
‘In the case of the Maidenhead bridge, the contractor being alarmed
at learning that the arch was the flattest known in brick, Brunel
pointed out to him that the weight which he feared would crush the
bricks, would be less than in a wall which he, the contractor, had
recently built, and he convinced him by geometry, made easy by
diagrams, that the bridge must stand. Knowledge of detail Brunel
shared with the carpenter, builder, or contractor for earthwork,
and he was their superior in the accuracy and rapidity with which
he combined his knowledge, and arrived at correct conclusions as to
the cost of the work and the time it would take to execute it.
‘In talking to landowners and others whose opposition it was
important to overcome, I have often been struck by your father’s
great powers of negotiation. The most absurd objections--and there
were many such--were listened to with good humour, and he spared no
pains in explaining the real facts, so that it sometimes happened
that he converted opponents into supporters of the railway. In the
course he took there was much skilful diplomacy, but there was no
dishonesty, no humbug. He was very frank and perfectly sincere. His
object was to impart his own convictions, and in that he often
succeeded.
I never met his equal for sustained power of work. After a hard day
spent in preparing and delivering evidence, and after a hasty
dinner, he would attend consultations till a late hour; and then,
secure against interruption, sit down to his papers, and draw
specifications, write letters or reports, or make calculations all
through the night. If at all pressed for time he slept in his
armchair for two or three hours, and at early dawn he was ready for
the work of the day. When he travelled he usually started about
four or five in the morning, so as to reach his ground by daylight.
His travelling carriage, in which he often slept, was built from
his own design, and was a marvel of skill and comfort. This power
of work was no doubt aided by the abstemiousness of his habits and
by his light and joyous temperament. One luxury, tobacco, he
indulged in to excess, and probably to his injury. At all times,
even in bed, a cigar was in his mouth; and wherever he was engaged,
there, near at hand, was the enormous leather cigar-case so well
known to his friends, and out of which he was quite as ready to
supply their wants as his own.
His light and joyous disposition was very attractive. At no time
was he stern, but when travelling or off work he was like a boy set
free. There was no fun for which he was not ready. On the old Bath
road, on a Wiltshire chalk hill-side, is cut a large horse, the
pride of the district, and only inferior in reputation to that of
the famous Berkshire vale. The people of the district, afraid to
lose their coach traffic, were violently opposed to the Great
Western Railway Bill. Talking over this one evening, some one
suggested turning the horse into a locomotive. Brunel was much
amused at the idea, and at once sketched off the horse from memory,
roughly calculated its area, and arranged a plan for converting it
into an engine. Ten picked men were to go down in two chaises, and
by moonlight to peg and line out the new figure, and then cut away
the turf, and with it cover up as much of the horse as might be
left. From the tube was to issue a towering column of steam, and
below was to be inserted in bold characters the offensive letters
G. W. R. It was, of course, not intended to carry this joke into
execution, but Brunel often alluded to it, and laughed over the
sensation it would have created.
‘He possessed a very fine temper, and was always ready to check
differences between those about him, and to put a pleasant
construction upon any apparent neglect or offence. His servants
loved him, and he never forgot those who had stood by his father
and himself in the old Tunnel days of trouble and anxiety.
‘No doubt the exertions of those three years, though they laid the
foundation, or rather built the fabric, of his reputation, also
undermined his constitution, and eventually shortened his life.
Everything for which he was responsible he insisted upon doing for
himself. I doubt whether he ever signed a professional report that
was not entirely of his own composition; and every structure upon
the Great Western, from the smallest culvert up to the Brent
viaduct and Maidenhead bridge, was entirely, in all its details,
from his own designs.’
In the press of work and the altered circumstances under which he
superintended the construction of his later railways, many changes
inevitably followed. The open britzska gave place to a close travelling
carriage, which in its turn became useless; and no time was left for fun
or practical jokes; but the same energy of mind and the same kindliness
of heart remained uninfluenced by increasing occupations or advancing
years.
CHAPTER V.
_THE BROAD GAUGE._
ORIGIN OF THE ORDINARY GAUGE OF RAILWAYS--ADOPTION BY MR. BRUNEL OF
THE BROAD GAUGE ON THE GREAT WESTERN RAILWAY--REASONS FOR ITS
ADOPTION--THE PERMANENT WAY--REPORTS OF MR. NICHOLAS WOOD AND MR.
JOHN HAWKSHAW, 1838--EXTRACT FROM REPORT OF DIRECTORS OF GREAT
WESTERN RAILWAY COMPANY (DECEMBER 20, 1838)--EXTENSION OF THE BROAD
GAUGE SYSTEM--BREAK OF GAUGE--ROYAL COMMISSION ON THE GAUGE OF
RAILWAYS, 1845--LETTER OF MR. BRUNEL ON THE BROAD GAUGE (AUGUST 6,
1845)--GAUGE ACT OF 1846--THE MIXED GAUGE--REPORT OF RAILWAY
COMMISSIONERS, 1847--NORTHERN EXTENSIONS OF THE GREAT WESTERN
RAILWAY--ADVANTAGES OF THE BROAD GAUGE--PARTIAL ABANDONMENT OF THE
BROAD GAUGE.
The railways designed by Mr. Brunel were, with a few exceptions,
distinguished from those in all other parts of England by a peculiarity
in the width between the two rails forming each line of way, or in what
is called the _gauge_. In most railways, the distance between the
internal edges of the rails is 4 feet 8½ inches, being what is termed
the _narrow gauge_; on Mr. Brunel’s railways, it was seven feet, or what
is termed the _broad gauge_.
* * * * *
The gauge of the earlier railways, which were but a modification of the
old wooden tramway, was made that of the tram plates which they
superseded; and this had been originally fixed to suit the distance
between the wheels of the country carts in the north of England.
When Mr. George Stephenson introduced the locomotive engine, the gauge
of the lines in the Northumberland district had been already fixed. In
laying out the Stockton and Darlington line (1821-1825) he saw no reason
to depart from the gauge he had previously adopted; and, indeed, some of
the waggons to be used on this line were brought from the
Northumberland collieries. In this way the first important railway in
England was made with the gauge of 4 feet 8½ inches; not from a
deliberate choice of this width on the ground of any peculiar
advantages, but from the mere fact of its already being established
elsewhere.
In the construction of the Manchester and Liverpool Railway, in 1826,
the same gauge was adopted as on the Stockton and Darlington; this
course was also followed by the Grand Junction and the London and
Birmingham Railways, and thus the 4 feet 8½ inches gauge became
established in that part of the country.
* * * * *
Long experience appears to have determined the general type of wheeled
vehicles: the wheels being of somewhat large size, and the body placed
between them, so as to come down close upon the axle-tree.
This type, which gives obvious advantages in a mechanical point of view,
appears to have been adhered to in all railway vehicles used before the
opening of the Liverpool and Manchester Railway; these, however, were
chiefly coal-waggons. But on the Liverpool and Manchester Railway it was
soon perceived that the great increase of carrying power which the
railway afforded must be met by a corresponding increase of space in the
rolling stock, as it was necessary to accommodate light bulky goods and
passenger traffic. The available width between the wheels was limited to
about 4 feet 6 inches, and to carry in this width any large amount of
cotton goods, or of passengers, would have required a train of an
inordinate length. To meet this difficulty a new form of vehicle was
designed; the wheels were made small, and the body was raised and
widened out, projecting on either side over the tops of the wheels.
The earliest description of this form of waggon is contained in the
second edition of Wood’s ‘Practical Treatise on Railroads,’ published in
1832, about two years after the opening of the Liverpool and Manchester
Railway. In Plate III., Mr. Wood shows a truck with a raised platform
overhanging the wheels, and adapted for carrying loose boxes of coals;
adding, in the description:
Although the drawing shows only the form of boxes used for the
conveyance of coals, yet it will readily occur that the form can be
varied to suit the carriage of any kind of articles; the framework
or body of the carriage being raised above the wheels, the breadth
can be extended to any width which the distance between the
railways [i.e. between the up and down lines of road] will admit
(p. 75).
Such was the state of matters when, in the year 1833, Mr. Brunel was
appointed Engineer of the Great Western Railway. With the view of
leaving the question of gauge open for future consideration, he procured
the omission in the Great Western Act of a clause defining it. He came
to the conclusion that it would be desirable to adopt a wider gauge, and
he recommended this measure to the Directors in a report dated October
1835.[47]
* * * * *
In October 1836 a Royal Commission, consisting of Mr. Drummond,
Under-Secretary for Ireland, Mr. R. Griffith, Colonel (now
Field-Marshal) Sir John Burgoyne, R.E., and Professor Barlow, of
Woolwich, was appointed to report on the establishment of railways in
Ireland. They considered carefully the question of gauge, and their
arguments in favour of an increase in the gauge were afterwards stated
by Mr. Brunel to be identical with his own.
They drew attention to the advantage of large wheels, the use of which
would be facilitated by a wider gauge; and they thought it a matter of
importance to be able to place the bodies of the carriages between the
wheels, instead of over them.
* * * * *
It was the width of the carriages, and not the distance between the
rails, that determined the general dimensions, and therefore the cost,
of the works of a railway. Mr. Brunel saw many advantages to be gained
by an increase in the gauge, even while retaining the existing
dimensions of carriages; and he thought it unwise at the commencement of
a work of such magnitude as the Great Western Railway to retain a limit
the inconvenience of which had already become apparent.
He says, in his evidence before the Gauge Commission:
Looking to the speed which I contemplated would be adopted on
railways, and the masses to be moved, it seemed to me that the
whole machine was too small for the work to be done, and that it
required that the parts should be on a scale more commensurate with
the mass and the velocity to be attained. (Q. 3924.)
The width between the rails being the fundamental dimension of ‘the
whole machine,’ on which its entire development must depend, Mr. Brunel
proposed to begin by the enlargement of this dimension, and recommended
that on the Great Western Railway the gauge should be seven feet. He
considered that the whole of the parts of the railway and of its rolling
stock would be susceptible of continual, though gradual improvement, and
that it was highly advisable to remove, in the outset, a great obstacle
in the way of this progress.
He did not in the first instance propose any important change in the
details as consequent on the wider gauge; and in regard to one of the
principal points, the diameter of the wheels, he said:--
I am not by any means prepared at present to recommend any
particular size of wheel, or even any great increase of the present
dimensions. I believe they will be materially increased; but my
great object would be in every possible way to render each part
capable of improvement, and to remove what appears an obstacle to
any great progress in such a very important point as the diameter
of the wheels, upon which the resistance, which governs the cost of
transport and the speed that may be obtained, so materially
depends. (Report in Appendix I. p. 532.)
Mr. Brunel also looked forward to the advantages which a wider gauge
would give for the construction of the locomotive engines. Difficulties
had been already experienced from the limited width between the wheels,
which cramped the machinery, rendering it difficult of access for
repairs; it also limited the size of the boiler and fire-box, on which
the power depended. For this reason Mr. Brunel considered that a wider
gauge would present great advantages, as it would allow the locomotives
to be constructed of greater power, and with their machinery arranged in
a more advantageous manner. He also thought that the greater width of
base for the carriages would give increased steadiness and smoothness of
motion, with greater safety, particularly at high speeds, and that there
would be the advantage of being able to use larger wheels for the
carriages. Moreover, he had in view the possibility which the broad
gauge would give of adopting wheels of a still larger diameter without
raising the centre of gravity, the body of the carriage being placed
between them, as in the original type of common road vehicles.
The broad gauge was also considered by Mr. Brunel in prominent
connection with the peculiarly favourable circumstances of the Great
Western line, in regard to its gradients and curves. He thought that
‘it would not have been embracing all the benefits derivable from the
gradients of the Great Western Railway, unless a more extended gauge was
adopted.’ In the first place, it was evident that a diminution of the
frictional resistance would present the greatest advantage where the
gradients were flat. In regard to curves, the wider gauge was at that
time considered by him to be more advantageously applied where the
curves were of large radius than where they were sharp.[48] On the Great
Western Railway both gradients and curves were remarkably good; with the
exception of two inclines of 1 in 100, on which auxiliary power was
proposed to be used, there was no gradient between London and Bristol
steeper than 1 in 660, the greater part of the line being nearly level,
and except between Bath and Bristol there was no curve sharper than
about one mile radius.
For these reasons Mr. Brunel thought that unusually high speed might
easily be attained for passengers, and great tractive power for goods.
He said:--
I shall not attempt to argue with those who consider any increase
of speed unnecessary. The public will always prefer that conveyance
which is the most perfect, and speed, within reasonable limits, is
a material ingredient in perfection in travelling. (Report in
Appendix I. p. 532.)
In deciding that the distance between the rails should be seven feet,
Mr. Brunel seems to have been guided by the principle that the wheels
should be put sufficiently far apart to admit of an ordinary carriage
body being placed between them.[49]
Mr. Brunel did not anticipate that the difference between the gauge he
proposed and that of other railways would lead to any important
inconvenience. The views he held on this subject were expressed fully by
him in a report of December 13, 1838. He says, speaking of the
difficulty of communication between the Great Western and other
railways:--
This is undoubtedly an inconvenience; it amounts to a prohibition
to almost any railway running northwards from London, as they must
all more or less depend for their supply upon other lines or
districts where railways already exist, and with which they must
hope to be connected. In such cases there is no alternative.
The Great Western Railway, however, broke ground in an entirely new
district, in which railways were unknown. At present it commands
this district, and has already sent forth branches which embrace
nearly all that can belong to it; and it will be the fault of the
company if it does not effectually and permanently secure to itself
the whole trade of this portion of England, with that of South
Wales and the south of Ireland; not by a forced monopoly, which
could never long resist the wants of the public, but by such
attention to these wants as shall render any competition
unnecessary and hopeless. Such is the position of the Great Western
Railway. It could have no connection with any other of the main
lines, and the principal branches likely to be made were well
considered, and almost formed part of the original plan; nor can
these be dependent upon any other existing lines for the traffic
which they will bring to the main trunk.
Mr. Brunel was not singular in holding the opinion that it would be
desirable to allot a given district to one railway, which might
conveniently serve it by means of a trunk line and branches of a special
gauge. In the Eastern Counties line, designed in 1836, by Mr.
Braithwaite, and opened in 1839, a gauge of 5 feet was adopted; and Mr.
Robert Stephenson, as engineer of another line, the Northern and Eastern
Railway, branching out from the Eastern Counties to the northward,
adopted the same gauge. It was not till the Northern and Eastern line
was extended, some years afterwards, that the rails of the whole system
were altered to the narrow gauge.
* * * * *
Mr. Brunel’s recommendation was adopted by the Directors of the Great
Western Railway; and, in their report of August 25, 1836, after
observing that the generally level character of the line would greatly
facilitate the attainment of a higher speed of travelling, they pointed
out the advantages of the broad gauge, and stated that engines had been
ordered specially adapted to the nature of the line, which would be
capable of attaining with facility a rate of from thirty-five to forty
miles per hour.
The line was opened between Paddington and Maidenhead on June 4, 1838,
and the performance of the engines was considered satisfactory, trains
of eighty tons and upwards being drawn at speeds of from thirty-eight to
forty miles per hour.
* * * * *
Notwithstanding these favourable results, the change in regard to the
gauge did not pass unquestioned. Attacks were made on it in various
quarters, and considerable excitement was caused among the shareholders
and the public.
It was asserted that the width of 4 feet 8½ inches was exactly the
proper width for all railways, and that a deviation from it was
tantamount to the abandonment of an established principle which
experience had proved to be correct. It was further alleged that the
cost of all the works connected with the formation of the line would be
greatly increased; that the carriages must be stronger and heavier,
that they would not run round the curves, and would be liable to run off
the rails, and particularly that the increased length of the axles would
render them liable to be broken. These were not advanced as difficulties
which, existing in all railways, might be somewhat increased by the
increase of gauge, but they were assumed to be peculiar to the broad
gauge, and fatal to it. Some urgent representations appear to have been
made to the Directors; for in their report of August 15, 1838, they
state, that as the gauge and the permanent way, which had also been the
subject of adverse criticism, had been sources of some anxiety to them,
they had applied to three of the most eminent authorities on the
construction and working of railways--Mr. James Walker, President of the
Institution of Civil Engineers, Mr. Robert Stephenson, and Mr. Nicholas
Wood, of Newcastle-on-Tyne--to undertake a thorough inspection of the
line, to investigate the working of it, and to give their opinion on the
plan adopted.
Mr. Walker and Mr. Stephenson declined the task, on the ground that they
did not wish to become embroiled in professional controversy, but Mr.
Wood undertook it; and a similar commission was afterwards given to Mr.
Hawkshaw.
In order to put the shareholders fully in possession of all the
information in their power, the Directors published a very complete
statement by Mr. Brunel on the arrangements adopted by him. It will be
seen that in this report, which is given in Appendix I. p. 525, he
states his original arguments, and answers the objections brought
against his plans; and he contends that the result of experience
establishes their success. In regard to the gauge, he says:--
Everything that has occurred in the practical working of the line
confirms me in my conviction that we have secured a most valuable
power to the Great Western Railway, and that it would be folly to
abandon it.
But the two engineers, to whom the consideration of this matter had been
referred, differed materially in opinion from Mr. Brunel. The nature of
their investigations and reports, and of Mr. Brunel’s replies, is stated
in the extracts given below from the report of the Directors in January
1839.
* * * * *
In addition to the question of gauge, another important matter referred
to the consideration of Mr. Wood and Mr. Hawkshaw was the construction
of the permanent way.[50] On the Great Western a construction had been
introduced by Mr. Brunel differing materially from that ordinarily used;
and as defects had shown themselves after the opening of the railway,
some anxiety was felt in reference to it by many of the shareholders.
The subject of the permanent way adopted on the Great Western Railway
does not necessarily belong to the gauge question, and would, perhaps,
have been more properly considered in the chapter on Mr. Brunel’s
railway works; but, as a matter of fact, the controversy concerning it
became so interwoven with that of the broad gauge, that in a historical
account it would be difficult to separate them.
It appeared to Mr. Brunel that, with a view of applying the engine power
to the greatest advantage, particularly in attaining high speed, more
attention ought to be paid to the construction of the permanent way. He
says, in a report dated February 1837:--
It appears to be frequently forgotten that although lofty
embankments and deep cuttings, bridges, viaducts, and tunnels are
all necessary for forming the level surface upon which the rails
are to be laid, yet they are but the means for obtaining that end;
and the ultimate object for which these great works are
constructed, and for which the enormous expenses consequent upon
them are incurred, consits merely of four level parallel lines, not
above two inches wide, of a hard and smooth surface; and upon the
degree of hardness, smoothness, and parallelism (which last has
hitherto been very much neglected) of these four lines depend the
speed and cost of transport, and in fact the whole result aimed
at....
In forming all my plans I have looked to the perfection of the
surface on which the carriages are to run, as the great and
ultimate desideratum; and in the detail of construction of this
last operation, without which all the previous labour is
comparatively wasted, I have always contemplated introducing all
the perfection of materials and workmanship of which it is capable.
With a view to improvement on this point, Mr. Brunel considered it would
be advantageous if two important changes were made. He proposed, in the
first place, to abolish the use of stone blocks for the rails to rest
on, and to substitute timber; and, secondly, to apply the support
uniformly and continuously along the whole length of the rails, instead
of only at intervals.
The first of these changes, namely, the substitution of timber for
stone, was not wholly new, for transverse wood sleepers were often used
in exceptional situations; but it was the general opinion that stone,
where it could be applied, formed the best support for the rails,[51]
and the exclusive employment of timber was considered a great
innovation.
The other principle, that of ‘continuous bearing,’ was similar to that
of the old wooden and stone tramways; and, even as applied to iron rails
it had been extensively used before, as Mr. Brunel mentions in his
report of August 1838 (see Appendix I. p. 535.)
Mr. Brunel designed for this continuous bearing a peculiar shape of
rail, which, from the form of its section, acquired the name of the
‘bridge rail.’ The rail was bolted down to the longitudinal timbers, and
the timbers of the two rails were connected together at intervals by
cross-pieces, called transoms, bolted to them; these served to keep the
two rails at a proper distance apart. The longitudinal timbers lay on
gravel or other ‘ballast,’ which had been found to form the best
foundation, as being firm and solid, easy of adjustment, and allowing
free drainage.[52]
Mr. Brunel, however, thought there would be difficulty in giving the
longitudinal baulks a sufficiently solid bearing on the gravel below
them.
A similar difficulty had already been experienced with the heavy stone
blocks used on other railways. As a remedy for this, Mr. Stephenson
caused each block to be lifted and dropped several times on its place,
so as to consolidate the ballast below.
The same thing could not be done with a long wooden baulk, and Mr.
Brunel therefore contrived another mode of overcoming the difficulty.
Piles were driven into the ground between the rails, and their heads
bolted to the cross-transoms, the object being to hold the timber
framework firmly down. The gravel was then rammed hard under the
longitudinal baulks, to give the consolidation desired. The result,
however, of this mode of construction was far from successful, and the
state of the road, when run over by the trains, was in many places very
defective.[53]
In the course of his enquiry Mr. Wood tried a large number of
experiments on the Great Western and other lines. He was of opinion that
stone blocks afforded a permanently firmer base, and so caused less
resistance to the train, but that there was less noise with continuous
timber bearings, and that they gave a smoother and a more perfect road
for high rates of speed. He thought, however, that the piles were
objectionable, and that the weight of the trains would in the course of
time sufficiently consolidate the foundation. Mr. Brunel accepted Mr.
Wood’s conclusions and abandoned the piling, adopting at the same time
larger timbers and heavier rails.
The experience of the permanent way, as thus altered, fully justified
the favourable anticipations Mr. Brunel had formed of the continuous
timber bearing.[54]
* * * * *
After the reports of Mr. Wood and Mr. Hawkshaw, with Mr. Brunel’s
replies to them, had been circulated among the shareholders, a special
general meeting was called in London, to receive and consider these
documents. It was convened for December 20, 1838, but was adjourned till
January 9, 1839. This meeting was of great importance, not only to the
Company, but to Mr. Brunel personally, as on the resolutions to be
passed depended whether or not his plans should be proceeded with.
He had, however, the warm support of the Directors, as will appear from
the following extracts from their report.
It may be here concisely stated, that Mr. Wood deduces from
experiments upon the performance of engines on the Great Western
and other lines, that although a higher rate of speed has been
attained on the former, it would appear only to have been
accomplished by the increased power of the engines, with a much
greater consumption of coke when calculated per ton per mile. He
ascribes this result principally to the resistance presented by the
atmosphere to the motion of railway trains, especially at high
rates of speed. His remarks on that subject are qualified, however,
by the expression of a doubt as to the value to be assigned to the
single set of experiments on each of two inclined planes, which are
quoted as the authority for the degree of atmospheric resistance
supposed to have been discovered.
The reduction of friction by the employment of wheels of increased
diameter, and the benefit of lowering the carriages between the
wheels, are affirmed by Mr. Wood as incontrovertible. The increased
stability, and consequent increased steadiness of motion to
carriages on the wider base, are also admitted by him....
The various propositions of doubtful advantage from the wide gauge,
as well as of alleged objection to it, appear to have been
thoroughly considered in the report in question. The experiments on
the consumption of coke at high velocities were unfavourable, and,
in connection with the theory of atmospheric resistance, appear to
have influenced the mind of Mr. Wood to consider that a seven-feet
gauge was beyond the width which he would deem the best. At the
same time, upon a review of all the circumstances, and considering
that there are counteracting advantages, incidental to an increased
width of gauge, he does not think that the result of his enquiries
would justify a change in the dimensions adopted on this line, and
he recommends the present width should be retained.
The advice thus given by Mr. Wood, upon mature reflection, being
directly at variance with the conclusion at which Mr. Hawkshaw had
previously arrived upon an investigation similarly delegated to
him, it became the duty of the Directors to consider most
attentively the train of reasoning and argument which led the
latter to urge such an opposite course. Naturally expecting from
that circumstance to find in his report a clear and definite
statement of the positive loss or disadvantages accruing from the
increased width of gauge, the Directors could not fail to remark
with some surprise that he enforces his recommendation, not upon
any ascertained injury or failure in the plan, but almost
exclusively upon the presumption that all railways, however
disconnected or locally situated, should be constructed of one
uniform width. While he appears to think that it might be an
improvement to have an addition of a few inches, five or six at the
most, he still questions the expediency of any variation from the 4
feet 8½ inches gauge. Mr. Hawkshaw, in his report, also considers
any additional expense upon the gauge, as well as upon the
improvement of gradients, to be undesirable, and assumes it at a
scale of augmentation far beyond the real difference of cost. His
estimates on that head are impeached in the engineer’s
observations, and no doubt exists in the minds of the Directors,
that the subject, reduced to a mere question of figures, in its
present position, would undeniably show a pecuniary loss to be
borne by the Company by any such change of system as he advocates,
even if it were on other grounds deemed advisable. The objection
that the wide gauge might prevent a junction with other lines seems
both to Mr. Wood and the Directors to have but little weight, as
applied to the Great Western Railway. Already has the same width
been contemplated and provided for in the extension lines through
Gloucestershire to Cheltenham and from Bristol to Exeter. Any local
branches hereafter to be made would undoubtedly follow the same
course, and the proprietors, therefore, may be satisfied that no
apprehension need be entertained by them on that head.
The advantage of following Mr. Wood’s advice, in not making any
alteration in the width of way, has been since most forcibly shown
by more recent experiments, which have entirely changed the results
upon which the chief objections to the gauge were founded. The
performance of the engines, shown by Mr. Wood’s experiments in
September, gave such a disproportionate result in their power upon
the attainment of high velocities, as to render it all but
impossible that the effect could be entirely produced by the action
of the atmosphere on the trains. All doubts were shortly removed by
its being ascertained that a different cause (a mere mechanical
defect in the engine itself) had been in operation. If Mr. Wood had
witnessed these recent performances of the engines, he must
unquestionably have changed his opinions as to the means and
practicability of carrying full average loads at a high speed,
without the great increased expense of fuel. The Directors have
satisfied themselves of this very important fact, by personally
attending an experiment (accompanied by several gentlemen, among
whom was a very eminent practical mechanic), on which occasion the
‘North Star’ took a train of carriages, calculated for 166
passengers, and loaded to 43 tons, to and from Maidenhead, at a
mean average speed of thirty-eight miles per hour, the maximum
being forty-five miles per hour, consuming only 0·95, or less than
1 lb. of coke per net ton per mile, instead of 2·76, say 2¾ lbs.,
as previously shown. This was accomplished by a mere altered
proportion in the blast pipe of the engine, in the manner explained
by Mr. Brunel, being a simple adaptation of size in one of the
parts, which admits a more free escape of steam from the cylinder,
after it has exerted its force on the piston, still preserving
sufficient draft in the fire.[55]
It must be almost needless to point out to those who have perused
the reports, how importantly this change bears upon the subject in
almost every relation of the enquiry. It negatives the assumption
that the velocity can only be attained by a ruinous loss of power.
It establishes beyond doubt that the consumption of fuel as now
ascertained, in proportion to the load, is only one-third of that
which from the former experiments had been the basis of Mr. Wood’s
arguments. An analysis in the report of the performance of the
Great Western engines, with heavy loads varying from 80 tons to 166
tons, shows in every respect a peculiarly satisfactory result at a
small cost of fuel, and warrants the expectation of very great
benefit to the Company from the economical transport of goods on
the line. That the expenses of locomotive repairs, especially on
that heavy class of repair which arise from lateral strains on the
wheels and framing of the engines, have been materially less than
on other lines is ascertained by very detailed accounts, accurately
made and submitted to the Board by the superintendent of that
department. The experience of some months has now enabled the
Directors to witness the progressive improvement in the practical
working of the railway. A higher rate of speed has been generally
maintained than on other lines, and at the same time, with that
increased speed, great steadiness of motion has been found in the
carriages, with consequent comfort to the passengers. If speed,
security, and comfort, were three great desiderata in the original
institution of railway travelling, the Directors feel sure that the
public will appreciate and profit by any improvements in those
qualities, the Company deriving ample remuneration in the shape of
increased traffic. A saving of time upon a long journey, with
increased comfort, will necessarily attract to one line in
preference to another many travellers from beyond the ordinary
distance of local connection, and will thus secure a valuable
collateral trade which would not otherwise belong to it. It has
also a decided tendency to avert competition, which may with much
reason be regarded as the chief peril to which railway property is
subjected.
The Directors, upon a deliberate reconsideration of all the
circumstances affecting the permanent welfare of the undertaking,
divesting the question of all personal partialities or obstinate
adherence to a system, unanimously acquiesce in the abandonment of
the piles, in the substitution of a greater scantling of timber,
and of a heavier rail, retaining the width of gauge with the
continuous timber bearings, as the most conducive to the general
interests of the Company.
The views of the Directors were approved of by the majority of the
shareholders (the numbers being 7,792 for, and 6,145 against); and the
construction of the line was proceeded with according to Mr. Brunel’s
plans.
* * * * *
By June 30, 1841, the whole length of the Great Western Railway was
opened from London to Bristol. Some of the Directors’ reports mention
the fact that the speed uniformly maintained by the engines much
exceeded the ordinary rate of railway travelling, and allude to the
‘general testimony borne to the smoothness and comfort of the line and
carriages.’
* * * * *
As has been before mentioned, extensions and branches on the same gauge,
to all of which Mr. Brunel was engineer, were projected and ultimately
carried out, in accordance with the original scheme of the undertaking,
to Exeter, Plymouth, and Cornwall, and to Gloucester, Hereford, and
South Wales, as well as to Oxford, Windsor, and other towns in the
immediate neighbourhood of the line.
About 1844, the attention of the Company began to be directed to
projects involving extensions of a much more serious character, and
which were destined to have a powerful influence on the position of the
gauge question. During the railway mania, the Great Western Company
found it impossible to stand aloof from the contests which were going on
around them, and thought it necessary, in order to protect their own
interests, to extend their lines beyond the district to which they had
originally intended to confine themselves.
At the general meeting in August, an extension from Oxford to Rugby was
determined on, as ‘of the greatest importance to the Great Western
line.’ About the same time a broad-gauge line was promoted from Oxford
to Worcester, and thence by Kidderminster and Dudley to Wolverhampton,
in order to open an immediate communication with the Staffordshire and
Worcestershire districts. There were also rival projects on the narrow
gauge, promoted by the London and Birmingham Company; and the competing
plans were referred, as was the custom at that time, for the examination
of the Railway Department of the Board of Trade.
In regard to the communication from north to south, through Oxford, the
question was, where the break of gauge should be.[56] The Board of Trade
saw nothing in the relative merits of the gauges to determine this
question, and from commercial considerations, they recommended that the
change of gauge should be made at Oxford. On this and other grounds they
considered that the narrow gauge schemes to the north of Oxford were
preferable to those of the Great Western Railway.
The rival schemes then went before Parliament, and after a protracted
enquiry, obstinately fought between the parties, the decision was given
in favour of the Great Western lines, contrary to the recommendation of
the Board of Trade. It was, however, stated by the chairman of the
Commons Committee that the decision had been founded on the local and
general merits of the respective lines, without any reference to the
comparative merits of the two gauges. On this account some peculiar
provisions were made in the Acts; for though the lines were sanctioned
on the broad gauge, the proprietors were bound also to lay down narrow
gauge rails upon them, if required to do so by the Board of Trade. At
the same time the House of Commons, on the motion of Mr. Cobden, passed
a Resolution praying her Majesty to refer the gauge question to a Royal
Commission.
A Commission was issued in July; the Commissioners being three in
number--Sir J. M. Frederic Smith, R.E.; Mr. G. B. Airy, Astronomer
Royal; and Professor Barlow, of the Royal Military Academy, Woolwich.
They took a large amount of evidence, both oral and documentary, and
made some examinations of the working of the two gauges. Their report
was presented to Parliament early in the session of 1846.
Of forty-eight witnesses, thirty-five were advocates of the narrow
gauge; and against these were arrayed but four champions of the broad
gauge, all officers of the Great Western Railway:--Mr. Charles Alexander
Saunders, the secretary; Mr. Seymour Clarke, the traffic superintendent;
Mr. (now Sir Daniel) Gooch, the locomotive superintendent; and Mr.
Brunel.
The report was of considerable length, and in it the Commissioners
addressed themselves to three heads of enquiry, viz.:--
1. Whether the break of gauge was an inconvenience of so much importance
as to demand the interference of the legislature.
2. What means could be adopted for obviating or mitigating such
inconvenience.
3. Considerations on the general policy of establishing a uniformity of
gauge throughout the country.
The general conclusions arrived at on these points were thus summed up
by the Commissioners:--
1. That, as regards the safety, accommodation and convenience of
the passengers, no decided preference is due to either gauge, but
that on the broad gauge the motion is generally more easy at high
velocities.
2. That, in respect of speed, we consider that the advantages are
with the broad gauge; but we think the public safety would be
endangered in employing the greater capabilities of the broad gauge
much beyond their present use, except on roads more consolidated,
and more substantially and perfectly formed, than those of the
existing lines.
3. That, in the commercial case of the transport of goods, we
believe the narrow gauge to possess the greater convenience, and to
be the more suited to the general traffic of the country.
4. That the broad gauge involves the greater outlay, and that we
have not been able to discover, either in the maintenance of way,
in the cost of locomotive power, or in the other annual expenses,
any adequate reduction to compensate for the additional first cost.
Therefore, esteeming the importance of the highest speed on express
trains for the accommodation of a comparatively small number of
persons, however desirable that may be to them, as of far less
moment than affording increased convenience to the general
commercial traffic of the country, we are inclined to consider the
narrow gauge as that which should be preferred for general
convenience, and therefore, if it were imperative to produce
uniformity, we should recommend that uniformity to be produced by
an alteration of the broad to the narrow gauge....
Guided by the foregoing considerations, the Commissioners recommended
that 4 feet 8½ inches should be fixed by law as the standard gauge of
the country; and that as to the existing broad gauge lines, either they
should be altered to the narrow gauge, or some course adopted which
would admit of narrow gauge carriages passing along them.[57]
This adverse report was a great surprise to the supporters of the broad
gauge system, as rumours had led them to hope for a different result.
Immediately after its appearance, several documents were published,
containing powerful and severe strictures on the proceedings and
opinions of the Commissioners. The most important of these was written
by Mr. Saunders, Mr. Daniel Gooch, and Mr. Brunel. It occupied fifty
closely printed folio pages, and was entitled, ‘Observations on the
Report of the Gauge Commissioners, presented to Parliament.’ To this,
‘Supplemental Observations’ were added, after the publication of the
Evidence and the Appendix to the Report.
In the conclusion of the ‘Observations’ the writers gave a summary of
the points they considered to have been proved in the controversy,
namely--
* * * * *
That the question of ‘break of gauge’ originated as a cloak to a
monopoly.
That even if the gauge were uniform, through trains would be
impracticable.
That the transfer would be of little inconvenience.
That any advantage of small waggons was applicable to the broad gauge,
but that the advantage of large waggons was not applicable to the
narrow.
That the competition between the two systems was advantageous.
That the final recommendations of the Commissioners were at variance
with their separate conclusions.
That it would be unjust to refuse to allow the broad gauge to be laid
down on lines for which it was already sanctioned by Parliament.
That the enquiry before the Commissioners was not properly conducted,
and that consequently no legislation ought to be founded on it.
That the data published by the Commissioners were often wrong, and in
some cases led to the reverse of their conclusions.
That greater economy was proved on the broad gauge.
That the broad gauge was superior in the points of safety, speed, and
conveyance of troops.
That the experiments made in the presence of the Commissioners had
demonstrated beyond all controversy the complete success of the
broad-gauge system.
For these and other reasons, a strong protest was made against any
legislative interference with the broad-gauge system.
A reply was published to these arguments; and during the controversy a
large number of pamphlets, articles, and other publications appeared on
both sides.
* * * * *
Mr. Brunel’s views on the whole question, about this time, are concisely
expressed in the following letter, written to a friend in France, who
asked for information on the subject of the broad gauge:--
August 4, 1845.
I am just off for Italy, but write a few hasty lines in reply to
Mons. ----’s queries, and which you must scold him for not
addressing direct to me. Nobody can answer such questions but
myself, and I am compelled to be very brief.
In answer to the _first_, I send a drawing.
_Secondly._ I see no reason why the ordinary construction of
rails, chairs, and sleepers should not be equally applicable to
the wide gauge as to the narrow. I have used them occasionally. I
should think 75 lbs. per yard heavy enough for any purposes.
_Thirdly._ Within all ordinary limits, certainly in curves of more
than 250 metres [12½ chains] radius, the gauge does not affect the
question of curves. The effect of a curve of larger radius than
this appears, both from much observation as from theory, to arise
merely from _two_ causes, the one centrifugal force, which is
easily neutralised, and is independent of gauge; the other from the
axles not being able to travel in the direction of the radius, and
consequently the wheels not running in a tangent to the curve. This
also is unaffected by the width of gauge. Practically I believe the
conditions are not altered.
_Fourthly._ The expenses of construction are not dependent on the
breadth of gauge unless the total width allowed for the loads or
carriages is thereby or for other reasons increased, which is not a
necessary consequence of a seven-feet gauge.
The wide gauge could be laid upon the London and Birmingham Railway
without altering any of the works, but in constructing the Great
Western Railway I thought it desirable to provide for carrying
larger bodies, and I placed the centres of the two railways 13 feet
apart, instead of 11 feet, and therefore my railway became _four_
feet wider in total width.
The increased cost of this, including the cost of land, will vary
from 300_l._ to 500_l._ per mile.
_Fifthly._ The increase of width will not increase the weight of an
engine (of the same power) 500 lbs., but I avail myself of the
larger width to get more powerful engines, and they weigh, with
water in the boiler, 18 to 21 tons. I send a drawing of one; the
stroke is 18 inches.
_Sixthly._ The passenger carriages are all on six wheels, and
excessively strong; at present the framework of carriages and the
whole of the waggons are made of iron. The first-class carriages
weigh, with wheels, &c., 7 tons 16 cwt. (17,472 lbs.), and carry 32
passengers. Second-class about the same weight, and hold 72.
_Seventhly_ and _Eighthly_. The comparison being on different
railways under different managements and totally different
circumstances, no strictly correct comparative results can be
given; and of course the most opposite opinions are entertained and
expressed. I believe we travel much quicker at the same cost and
with more ease, and certainly the wear and tear of engines and
carriages is _very much less_ with us than with the other lines;
but for the reasons above stated it cannot be made matter of exact
proof, but remains matter of opinion.
The report of the Gauge Commission, on being presented to Parliament,
was referred by the House of Commons to the Board of Trade, who reported
on it in June 1846. They did not, however, concur with the Commissioners
to the full extent of their recommendations; for, while admitting the
break of gauge to be an evil, they could not, having regard to the
circumstances under which the broad gauge companies had been
established, and the interest they had acquired, recommend either that
the broad gauge should be reduced to narrow, or that rails should be
laid down for narrow gauge traffic over all their lines. Such measures
would involve great expense, and they were unable to suggest any
equitable mode of meeting it.
This conclusion necessarily affected the opinion of the Board of Trade
in regard to the several lines under construction connected with the
Great Western Railway, which the Board recommended should be all made on
the broad gauge.
In regard to the broad-gauge lines sanctioned by Parliament from Oxford
to Rugby, and from Oxford to Worcester and Wolverhampton, the Board
determined to exercise their powers in requiring the narrow gauge to be
laid down, in addition to the broad.
The House of Commons adopted the recommendations of the Board of Trade,
and passed a series of resolutions in conformity thereto, and ‘An Act
for regulating the Gauge of Railways’ received the Royal Assent on
August 18, 1846.
It was enacted that it should not be lawful to construct any new
passenger railway on any other gauge than 4 feet 8½ inches in England,
and 5 feet 3 inches in Ireland.
Exceptions, however, were made in favour of certain lines in the west of
England and South Wales.
The provisions relating to the gauge in the Acts for the Oxford and
Rugby, and the Oxford, Worcester, and Wolverhampton Railways, were left
in force.
The Act also generally excepted ‘any railway constructed or to be
constructed under the provisions of any present or future Act containing
any special enactment defining the gauge or gauges of such railway or
any part thereof.’
This Act, while it professed to establish the narrow gauge as the
standard throughout the kingdom, did so only nominally; in reality, by
the words ‘present or future,’ in the passage above quoted, it left the
question of the gauge of any new railway open for the consideration of
the committee on the particular bill; and it only obliged the promoters
of the undertaking to adopt the narrow gauge when no case could be
proved by them for the adoption of some other. This was equivalent to
the former state of things, so that all the agitation of the question
had ended in a mere expression of opinion, and the broad-gauge party
were not only left with all their former liberty, but were encouraged,
and almost compelled, to push their system still farther wherever they
could.
* * * * *
About the time of the passing of the Gauge Act, a Board of Commissioners
of Railways was established, to whom the powers formerly possessed by
the Board of Trade were transferred.
One of the first duties of the Commissioners was to provide for the due
compliance with the order of the Board of Trade respecting the
introduction of the narrow gauge, in conjunction with the broad, on the
Oxford and Rugby Railway.
It was proposed to effect this either by laying a narrow gauge line
concentrically between the two rails of the broad gauge, or by laying
down only one additional rail between the two broad-gauge rails, making
one of the latter serve for both broad and narrow gauges. Mr. Brunel
recommended the second of these plans to be adopted on the Oxford and
Rugby line.
After a careful consideration of the question, the Commissioners
sanctioned the mixed gauge formed by the introduction of a third rail;
this was accordingly laid down, and none of the dangers which were at
the time prognosticated in reference to it were found to exist. It has
been the plan almost exclusively used in the many cases where the
combination of the two gauges has been required.
* * * * *
In 1846 the Great Western Railway Company had promoted a bill for a
branch to Birmingham from the Oxford and Rugby line at Fenny Compton.
The Act was obtained, but they were defeated on the question of the
gauge. However, after the passing of the Gauge Act, the Company again
attempted to carry the broad gauge to Birmingham. Their application was
backed by a strong memorial from the districts interested, and in June
1847 an order was passed by the House of Lords directing the Board of
Commissioners of Railways--
To inquire into the accommodation afforded by the several lines of
railway now open, or in the course of construction, or projected,
between London and Birmingham; and to report to this House, early
in the ensuing Session of Parliament in what manner they are of
opinion that the interests of the public may be most effectually
ecured in regard to such lines; and whether it is expedient that
the broad gauge should be extended to Birmingham; and if so, in
what manner such an arrangement can be carried into effect with the
least interference with existing interests....
This, of course, opened up again the whole question of the comparative
merits of the two gauges.
The Railway Commissioners issued a series of queries addressed to the
officials of the Great Western and the London and North Western Railway
Companies, and others. On the part of the Great Western, answers were
given by Mr. Brunel and Mr. Daniel Gooch. Mr. Gooch also furnished the
results, with tables and diagrams, of a very comprehensive series of
dynamometrical experiments, made by him on a mile of straight and level
line on the Bristol and Exeter Railway. These experiments fully
demonstrated the advantages of the broad gauge, and are still the chief
authority on train resistances.[58]
In their report the Commissioners adopted the opinion of the Gauge
Commissioners ‘that a break of gauge was a most serious impediment in
the transport of merchandise, and that the broad gauge did not offer any
compensating advantage so far as that description of traffic was
concerned.’ In regard, however, to passenger traffic, they found a case
for further enquiry. They said--
It is notorious that higher speeds, with larger and heavier
passenger trains, are regularly maintained on a part of the line of
the Great Western Railway than on any other railway in the country.
This fact is known and greatly appreciated by a very large portion
of the public; and no opinion respecting the extension of the
district within which the broad gauge should be adopted is likely
to be received with confidence which is not founded on a full
consideration of the circumstances to which the above fact is to be
attributed, and of the extent to which, under differing
circumstances, if attributable to the breadth of gauge, the gauge
of the Great Western Railway offers this advantage (p. 11).
They assumed that the greater speed was due to greater engine power, and
they admitted that the increase of gauge allowed of an increase in the
size and power of the locomotive. They arrived at the result that the
broad-gauge engine ‘can draw on a level an ordinary ‘passenger train of
60 tons with as much facility at ‘sixty miles an hour as the
narrow-gauge engines can at ‘fifty,’ the advantage, however, diminishing
with steep gradients. In their report the following passages are to be
found:--
Such appear to the Commissioners to be the advantages which the
broad gauge at present offers; and although they cannot consider
them sufficient to compensate the evils attendant on two gauges, if
it were now possible to obtain uniformity of gauge, yet, as two
gauges are established, it appears to them that it might be
expedient, and for the public interest, on account of those
advantages, to extend the broad gauge to Birmingham ... (p. 14.)
By introducing the mixed gauge on the Birmingham and Oxford
Junction Railway, the line from Birmingham by Fenny Compton to
London would probably offer, as a broad-gauge railway, as rapid a
communication as the existing direct line;[59] and great as the
advantages which the public have received by the rivalry between
the gauges, in the rapid improvement in railway travelling, have
been, it might even be expected that these would be further
increased when the two systems are brought into direct competition,
which as yet they have not been (p. 16).
The report of the Railway Commissioners was presented in May 1848. Their
decision was ratified by the passing of an Act in the same session for
extending the broad gauge from Oxford to Birmingham; and the line was
opened in October 1852.
Beyond Birmingham the Great Western Company purchased existing railways
leading through Wolverhampton and Shrewsbury to Chester, and obtained
access to Birkenhead and Manchester. It thus secured a communication
with the great Lancashire towns and the manufacturing districts.
But all the lines north of Wolverhampton had been constructed on the
narrow gauge, and therefore, unless the broad gauge had been laid down
on these lines, there was a break of gauge between the northern
districts and London.
The break of gauge was found to be a much more serious evil than had
been anticipated by the Great Western Company when they were fighting
their great battle in 1845. For passengers the inconvenience was
unimportant; but for the goods traffic between the manufacturing towns
and London it was serious, partly on account of the expense, but more
especially in consequence of the loss of time. The delay of some hours
by change of waggons, where great competition existed, was fatal.
For these reasons the abolition of the break of gauge became desirable.
The number of narrow-gauge lines had by the year 1861 been so increased
that there was no longer any hope of advantageously extending the broad
gauge in the north. Therefore the mixed gauge was completed to London.
After the establishment of the narrow-gauge communication on the
northern lines of the Great Western, and its prolongation to London,
there was but little inducement to use the broad gauge north of Didcot.
* * * * *
So far as it extended, the broad gauge had exhibited in a marked degree
the advantages Mr. Brunel claimed for it, and which were neither few nor
unimportant.
It may be desirable before concluding this chapter to sum up those
advantages:--
1. It gave the power of constructing more powerful engines, by which
greater speed for passenger trains and greater tractive power for heavy
goods trains were obtained.[60]
2. It gave more space for the convenient arrangement and beneficial
proportions of the machinery, as well as for convenient access to it. In
all these points difficulties had been found on the narrow gauge; and
the compulsory restriction of so important a dimension as the width
between the rails has been a bar to any improvements of great magnitude
or comprehensive nature.
3. It gave, even with the overhanging carriage, the facility for
obtaining large wheels, and consequently diminishing the axle friction
without sacrifice of stability.
4. The greater width of base for the carriages to rest on gave increased
steadiness and smoothness of motion, particularly at high speeds. It was
the impulse given by the increase of speed and comfort obtained without
difficulty on the broad gauge, which had led to the chief improvements
introduced in railway travelling.
5. Greater safety was secured, particularly at high speed, from the
greater stability of position due to the wider base, producing increased
steadiness and diminishing the chance under exceptional circumstances of
the derangement of any part of the train.
6. While the broad gauge was but little more costly than the narrow, the
width of the works being determined not by the width of the rails, but
by the width of the carriages, and the extra cost of rolling stock
being very small,[61] the broad gauge could be worked more economically
under parallel circumstances than the narrow.
7. It gave the facility of using broader vehicles with equal steadiness,
in cases where the extra breadth would be useful, though the extra
breadth was by no means an essential part of the scheme.
* * * * *
The truth of these assertions, as establishing the superiority of the
broad gauge, was of course vehemently denied by the advocates of the
narrow gauge.
One objection urged by them, the inconveniences of the break of gauge,
has undoubtedly been proved by experience to be a very powerful one, so
powerful indeed as to compel the abandonment of the broad gauge on the
lines where any considerable quantity of goods traffic has to be carried
in competition with other companies.
Had Mr. Brunel’s original plan been carried out, and had the broad-gauge
companies taken possession of all the western portions of England, and
avoided extensions into the north, the points of contact would no doubt
have been so unimportant that no great inconvenience would have arisen,
or a few miles of double gauge would have removed any difficulty; but,
under the actual circumstances of the case, the Great Western Company
were forced to yield.
* * * * *
The advantages of the broad gauge were so much appreciated by the
districts it served, that its abandonment was viewed with considerable
displeasure, particularly in the neighbourhood of Birmingham; but the
inconvenience of double traffic arrangements far outweighed the
advantages derivable from the use of the broad gauge, to the limited
extent it could be applied on those outlying portions of the Great
Western system. For these reasons the Company came to the determination
to work their northern lines on the narrow gauge only.
The broad gauge is therefore now confined to the district for which it
was originally intended. Even in this district there are many points of
contact with the narrow gauge; but the inconveniences of break of gauge
are by no means so important as they were in the north, and do not, at
present at least, menace the continued existence of Mr. Brunel’s
design.
CHAPTER VI.
_THE ATMOSPHERIC SYSTEM._
A.D. 1840--1848. ÆTATIS 35--43.
PRELIMINARY OBSERVATIONS--THE SOUTH DEVON RAILWAY--DESCRIPTION OF
THE ATMOSPHERIC SYSTEM--HISTORY OF ITS INTRODUCTION PRIOR TO
1844--REPORT BY MR. BRUNEL, RECOMMENDING ITS ADOPTION ON THE SOUTH
DEVON RAILWAY (AUGUST 19, 1844)--EXAMINATION OF THIS REPORT--MR.
BRUNEL’S EVIDENCE BEFORE THE SELECT COMMITTEE ON ATMOSPHERIC
RAILWAYS, 1845--HISTORY OF THE APPLICATION OF THE SYSTEM ON THE
SOUTH DEVON RAILWAY, 1844-1848--REPORT ON STATE OF WORKS (AUGUST
28, 1847)--REPORT ON CAUSES OF FAILURE (AUGUST 19,
1848)--ABANDONMENT OF THE SYSTEM, SEPTEMBER
1848--_NOTE_--COMPARISON OF STATIONARY AND LOCOMOTIVE POWER.
In the year 1844 Mr. Brunel recommended the adoption of the Atmospheric
System of propulsion on the South Devon Railway, a line of 52 miles in
length, which he was then constructing between Exeter and Plymouth. This
system had, under the management of Messrs. Clegg and Samuda, been in
operation with success on the Dalkey line for some time before Mr.
Brunel adopted their apparatus on the South Devon Railway. After it had
been in use on the South Devon for about twelve months, it was
abandoned, and the railway worked throughout by locomotives.
* * * * *
It is therefore as important as it is interesting to examine the causes
of the failure of the Atmospheric System, and to consider the reasons
which induced Mr. Brunel in the first instance to adopt it, and
afterwards to recommend its abandonment.
* * * * *
Up to about the year 1843, the cost of railways, which was in a great
measure due to the conditions imposed by the limited capabilities of the
locomotive, had prevented their construction, except in cases where they
would secure a large traffic, and at the same time traverse what was
then considered a practicable country.
A curvature of one mile radius was regarded as the maximum generally
admissible on a line where high speeds were aimed at, and auxiliary
locomotives were required to work heavy gradients.
Nevertheless, by the growing wants of the public and the growing
boldness of engineers, the railway system was gradually being forced
into districts hitherto regarded as unsuitable for it; and no country
was held to be impracticable where the gradients could be surmounted by
the inconvenient and costly expedient of auxiliary power.
* * * * *
The south of Devon had for several years demanded railway accommodation,
and at the period now under review, Mr. Brunel projected what was called
the coast line. This line, while it best accommodated the population of
the district, passed through a very difficult country. If it was to be
constructed at a moderate cost, curves of a quarter of a mile radius had
to be admitted; and above 30 miles of its entire length traversed a
district involving the adoption of gradients steeper than had been
elsewhere used for such considerable distances. The Act for this railway
was obtained in the Session of 1844.
* * * * *
The South Devon Railway, on leaving Exeter, crosses the flat country on
the right bank of the river Exe, as far as Starcross, a village nearly
opposite to Exmouth. From this point it runs down to the coast and along
the sea-shore, by Dawlish, to Teignmouth; being protected by a sea-wall
for the greater part of the distance, and passing through several
headlands by short tunnels. Beyond Teignmouth it follows the left bank
of the river Teign, which it crosses a short distance before reaching
the station at Newton Abbott. The portion of the line from Exeter to
Newton--21½ miles in length--is very nearly level, the steep inclines
for which the railway is noted being west of Newton. Between Newton and
Totness, for the first mile and a half the line is almost level, and in
the next two miles it rises 200 feet, with gradients of 1 in 100, 1 in
60, and nearly a mile of 1 in 43. At the summit is a short tunnel; and
thence the line descends 170 feet in a mile and three-quarters, with
gradients of 1 in 40 and 1 in 43 for about three-quarters of a mile, and
gradients of 1 in 57 and 1 in 88 for the rest of the incline. It then
runs with more moderate gradients and about a mile and a half of level
line to Totness.
From the valley of the Dart at Totness the line rises at once by a rapid
ascent of 350 feet in four miles and a half, with gradients varying from
1 in 48 to 1 in 90, more than a mile and a half averaging 1 in 50.
Thence it runs, with easy up and down gradients, for a distance of 12
miles along the skirts of Dartmoor, crossing by lofty viaducts the deep
valleys which penetrate the moor. It then descends to Plympton, in the
valley of the Plym, falling 273 feet in a little more than two miles,
with a gradient of 1 in 42½. From Plympton the line for two miles is
level, and then rises on an incline of 1 in 80 for a mile and a half,
and descends by a similar gradient into the Plymouth station.
The main characteristics of the railway are that, while it traverses a
very heavy country, its principal changes of level are concentrated into
four long and steep inclines. These four inclines were intended to be
worked by auxiliary power.
Hitherto on gradients of unusual steepness a stationary engine with rope
traction had been generally regarded as the only available expedient;
but the special difficulties by which this system was encumbered
rendered it unsuitable for high-speed passenger traffic, and practically
inapplicable to an extended line. It had, however, been very
successfully employed by Mr. Robert Stephenson on the Blackwall Railway,
a line of about 3¾ miles in length.
Messrs. Clegg and Samuda, the projectors of the Atmospheric System,
which was another mode of using stationary power, had, previously to
this period, laboured to attract the attention and win the favourable
opinion of engineers and the general public.
* * * * *
It is desirable, before proceeding further, to give a brief description
of this system of traction, upon the merits of which distinguished
engineers entertained widely different opinions.
Between the two rails of the line of way was laid a cast-iron tube,
which on the Croydon and Dalkey railways and the completed or level
portion of the South Devon Railway was fifteen inches in diameter. On
the inclines it was proposed to use a twenty-two inch tube.
At intervals of about three miles along the line were erected stationary
engines, working large air-pumps, by means of which air could be
exhausted from the tube, and a partial vacuum created within it. A
close-fitting piston was placed in one end of the tube, and the air
being exhausted from it, the pressure of the external air on the surface
of the piston which was towards the open end of the tube forced the
piston through the tube towards the end where the air-pumps were
working; so that if the piston were connected with a carriage running on
the rails, it would draw the carriage with it. The connection between
the piston and the carriage was arranged by Messrs. Clegg and Samuda in
the following way:[62] Along the top of the tube was a slit about 2½
inches wide; this slit was closed by a long flap of leather, which was
strengthened with iron plates, and secured to the tube at one side of
the slit. One edge of the leather thus formed a continuous hinge; the
other edge, where it closed on the tube, was sealed with a composition
of grease, to render it air-tight. This flap was known by the name of
the longitudinal valve.
When the valve was closed, the air could be exhausted from the tube in
front of the piston, and a partial vacuum formed. Behind the piston, the
air being at atmospheric pressure both within and without the tube,
there was no objection to opening the longitudinal valve; and a bar,
extending downwards from the under side of the carriage, entered the
slit obliquely under the opened valve, and was connected to the rear end
of a frame about ten feet long, the front end of which carried the
piston. To allow the bar to pass along the slit, the valve was opened on
its hinge, being pressed upwards by a series of wheels carried by the
moving piston-frame inside the tube. The valve closed again after the
passage of the train; and the tube was ready to be exhausted in
preparation for the passage of the next train.[63]
The Atmospheric System was first tried in 1840. An experimental tube was
laid down at Wormwood Scrubs on part of the short line now incorporated
into the West London Railway, and then known by the title of the
Bristol, Birmingham, and Thames Junction Railway. Its working was the
subject of eager discussion among engineers.
In 1842 Sir Frederic Smith, R.E., and Professor Barlow, under an order
from the Board of Trade, reported so favourably on the system with
reference to the proposal for its application on the Dalkey branch of
the Dublin and Kingstown Railway, that it was adopted there. In 1843 Mr.
(afterwards Sir William) Cubitt determined to employ it on the Croydon
Railway; and about the same time Mr. Robert Stephenson was desired by
the Directors of the Chester and Holyhead Railway to report on the
propriety of introducing it on that line.
Mr. Stephenson’s report was based on a series of experiments on the
working of the system at Dalkey. The view he took was adverse to its
adoption, not only on the Chester and Holyhead, but on almost every
railway whatsoever; and this on the ground that, though it was quite
capable of being developed into a practical working system, yet on lines
with ordinary gradients the atmospheric traction must be considerably
more costly than locomotive traction, and on steep gradients than rope
traction; in other words, that, as a mechanical appliance it was, though
practicable, not economical.
Mr. Stephenson’s report had no sooner appeared than the correctness of
his conclusions was disputed on his giving evidence before a Committee
of the House of Commons, in the spring of 1844, on the Croydon and
Epsom Railway Bill.
* * * * *
Mr. Brunel also was summoned as a witness. Previously to this time he
had taken a great interest in the various attempts which had been made
to introduce the Atmospheric System, and he had himself conducted
experiments at Wormwood Scrubs and at Dalkey. As early as July 1840 he
had considered its applicability to the Box Tunnel incline on the Great
Western Railway. He had also considered it in reference to various
projected lines; and in 1843 he recommended it for adoption in a long
tunnel on one of the steep inclines of the Genoa and Turin Railway, the
success of the system being then (he wrote) sufficient to justify its
use on a part of the line protected from weather. It was not, however,
applied on this railway.[64]
Mr. Brunel’s views at this time are indicated in the following letter:--
April 8, 1844.
Any part I have taken in examining into the system has been purely
from the desire which I always feel to forward good inventions; and
when I have formed a decided opinion, no fear of the consequences
ever prevents my expressing it. My great anxiety, however, is to
see a line of railway and all its appurtenances made expressly for
the Atmospheric System, and worked accordingly; until this is done
the results will be comparatively unsatisfactory.
Although unwilling to express general opinions, Mr. Brunel spoke
strongly before the Croydon and Epsom Railway Committee in favour of the
advantages of the Atmospheric System under certain circumstances, and
approved of its use on that line.
A few months later Mr. Brunel recommended the Directors of the South
Devon Railway Company to adopt the Atmospheric System, and they resolved
to act on his advice.
His report was as follows:--
August 19, 1844.
I have given much consideration to the question referred to me by
you at your last meeting--namely, that of the advantage of the
application of the Atmospheric System to the South Devon Railway.
The question is not new to me, as I have foreseen the possibility
of its arising, and have frequently considered it.
I shall assume, and I am not aware that it is disputed by anybody,
that stationary power, if freed from the weight and friction of any
medium of communication, such as a rope, must be cheaper, is more
under command, and is susceptible of producing much higher speeds
than locomotive power; and when it is considered that for high
speeds, such as sixty miles per hour, the locomotive engine with
its tender cannot weigh much less than half of the gross weight of
the train, the advantage and economy of dispensing with the
necessity of putting this great weight also in motion will be
evident.
I must assume also that as a means of applying stationary power the
Atmospheric System has been successful, and that, unless where
under some very peculiar circumstances it is inapplicable, it is a
good economical mode of applying stationary power.
I am aware that this opinion is directly opposed to that of Mr.
Robert Stephenson, who has written and published an elaborate
statement of experiments and calculations founded upon them, the
results of which support his opinion.
It does not seem to me that we can obtain the minute data required
for the mathematical investigation of such a question, and that
such calculations, dependent as they are upon an unattained
precision in experiments, are as likely to lead you very far from
the truth as not.
By the same mode M. Mallet and other French engineers have proved
the success of the system; and by the same mode of investigation
Dr. Lardner arrived at all those results regarding steam
navigation and the speed to be attained on railways, which have
since proved so erroneous.
Experience has led me to prefer what some may consider a more
superficial, but what I should call a more general and broader
view, and more capable of embracing all the conditions of the
question--a practical view.
Having considered the subject for several years past, I have
cautiously, and without any cause for a favourable bias, formed an
opinion which subsequent experiments at Dalkey have fully proved to
be correct; viz. that the mere mechanical difficulties can be
overcome, and that the full effect of the partial vacuum produced
by an air-pump can be communicated, without any loss or friction
worth taking into consideration, to a piston attached to the train.
In this point of view the experiment at Dalkey has entirely
succeeded. A system of machinery which even at the first attempt
works without interruption and constantly for many months, may be
considered practically to be free from any mechanical objection.
No locomotive line that I have been connected with has been equally
free from accidents.
That which is true for one railway of two miles in length is
equally true for a second or third, although they may be placed the
one at the end of the other; the chances of an accident are only in
the proportion of the number, or in other words, the length, a
proportion which holds equally good with locomotives, except that a
locomotive may be affected by the distance it has previously run,
while a stationary engine and its pipes cannot in like manner be
affected by the previous working of the neighbouring engine and
pipes.
In my opinion the Atmospheric System is, so far as any stationary
power can be, as applicable to a great length of line as it is to a
short one.
Upon all these points I could advance many arguments and many
proofs, but I shall content myself with saying that, as a
professional man, I express a decided opinion that, as a mechanical
contrivance, the Atmospheric apparatus has succeeded perfectly as
an effective means of working trains by stationary power, whether
on long or short lines, at higher velocity and with less chance of
interruption than is now effected by locomotives.
I will now proceed to consider the question of the advantage of its
application to the South Devon Railway.
It will simplify the discussion of the question very much if it is
considered as a comparison between a double line worked by
locomotives in the usual manner, and a single line of railway
worked by stationary power, the only peculiarity of the present
case being that upon four separate portions of the whole 52 miles
stationary assistant power would under any circumstances have been
used, these four inclines forming together one-fifth of the whole
distance.
It is necessary to consider it as a question of a single line on
account of the expense, the cost of the pipe for each line being
about 3,500_l._ per mile.
An addition of 7,000_l._ per mile, or of about 330,000_l._, in the
first construction could not be counterbalanced by any adequate
advantage in the saving in the works on the South Devon Railway,
and probably not by any subsequent economy or advantage in the
working; but the system admits of the working with a single line,
without danger of collision, certainly with less than upon a double
locomotive line. And I believe also that, considering the absence
of most of the causes of accidents, there will even be less
liability of interruption and less delay in the average resulting
from accidents than in the ordinary double locomotive railway.
By the modification of the gradients and by reducing the curves to
1,000 feet radius where any great advantage can be gained by so
doing, and by constructing the cuttings, embankments, tunnels, and
viaducts for a single line, a considerable saving may be effected
in the first cost.
In the permanent way and ballasting, the reduction will be about
one-half. I should propose to make the rails about 52 lbs. weight
and the timber 12 × 6; the quantity of ballast would probably be
rather more than half, but at the present prices of iron and timber
the saving could not be less than 2,500_l._ per mile.
From a careful revision of the works generally, I consider that a
reduction may be effected in the following items, and to the amount
specified in each, viz., ballasting gradients and curves:--
£ s. d.
Reduction in earth work 16,500 0 0
" in length of principal tunnel 14,000 0 0
--------------
30,500 0 0
_Saving by single line._
Earthwork 25,000 0 0
Tunnels 11,500 0 0
Viaducts 15,000 0 0
_Permanent way and ballast._
To allow for sidings, say 50 miles, 2,500_l._ 125,000 0 0
---------------
207,000 0 0
===============
_Per contra._
£
Pipe on 41½ miles[65] 138,500
Increase on inclined planes, 10½ miles 6,500 £ s. d.
145,000 0 0
Engines for the 41½ miles 35,000 0 0
Patent right, say 10,000 0 0
---------------
190,000 0 0
===============
The difference in first cost therefore is 17,000 0 0
To this must however be added the cost of the
locomotive power, with its attendant expenses
of engine-houses, &c., which cannot, I think,
be put at less than 50,000 0 0
--------------
Making a saving of 67,000 0 0
I have not included in the expense of the Atmospheric apparatus
that of the telegraph, because at its present reduced cost of
160_l._ per mile I am convinced its use would repay the outlay in
either case.
It would appear, then, that the line can be constructed and
furnished with the moving power, in working order, on the
Atmospheric System, for something less than the construction only
of the railway fitted for the locomotive power, but without the
engines; and that taking into consideration the cost of locomotive
power, a saving in first outlay may be effected of upwards of
60,000_l._
But it is in the subsequent working that I believe the advantages
will be most sensible.
In the first place, with the gradients and curves of the South
Devon Railway between Newton and Plymouth, a speed of thirty miles
per hour would have been, for locomotives, a high speed, and under
unfavourable circumstances of weather and of load, it would
probably have been found difficult and expensive to have maintained
even this; with the Atmospheric, and with the dimensions of pipes I
have assumed, a speed of forty to fifty miles may certainly be
depended upon, and I have no doubt that from twenty-five to
thirty-five minutes may be saved in the journey.
Secondly, the cost of running a few additional trains so far as the
power is concerned is so small, the plant of engines, the
attendance of engine-men, &c., remaining the same, that it may
almost be neglected in the calculations; so that short trains, or
extra trains with more frequent departures, adapted in every
respect to the varying demands of the public, can be worked at a
very moderate cost. I have no doubt that a considerable
augmentation of the general traffic will be thus effected, by means
which with locomotive engines would be very expensive, and
frequently unattainable, particularly as regards one class of short
trains, whether for passenger or goods, which from the
inconvenience of working them by locomotives are hardly known--I
refer to trains between the intermediate stations.
By many means, which the easy command of a motive power at any
time, at every part of a line, must afford of accommodating the
public, I believe the traffic may be increased.
It appears to me also that the quality of the travelling will be
much improved; that we shall attain greater speed, less noise and
motion, and an absence of the coke dust, which is certainly still a
great nuisance; and an inducement will thus be held out to those
(the majority of travellers) who travel either solely for pleasure,
or at least not from necessity, and who are mainly influenced by
the degree of comfort with which they can go from place to place.
Lastly, the average cost of working the trains will be much less
than by locomotives.
With the gradients of the South Devon Railway, and assuming that
not less than eight trains, including mail and goods trains,
running the whole distance, and certainly one short train running
half the distance, be the least number that would suffice, I think
an annual saving of 8,000_l._ a year in locomotive expenses,
including allowance for depreciation of plant, may very safely be
relied upon.
For all the reasons above quoted, I have no hesitation in taking
upon myself the full and entire responsibility of recommending the
adoption of the Atmospheric System on the South Devon Railway, and
of recommending as a consequence that the line and works should be
constructed for a single line only.[66]
In this report Mr. Brunel rested his recommendation principally on two
assumptions, which he held to be indisputable--(1) That stationary
power, if freed from incumbrances such as the friction and dead weight
of a rope, was superior to locomotive power; and (2) That the
Atmospheric System of traction was theoretically a good and economical
method of applying stationary power, and that it was also a practical
and working system, as had been shown in its first and somewhat crude
application at Dalkey.
The superiority of stationary as compared with locomotive power depends
on two principles--(a) That a given amount of power may be supplied by a
stationary engine at a less cost than if supplied by a locomotive. (b)
That the dead weight of a locomotive forms a large proportion of the
whole travelling load, and thus inherently involves a proportionate
waste of power--a waste which is enhanced by the steepness of the
gradients and the speed of the trains.
A detailed examination of these principles is given in the note to this
chapter.
It is there shown that at the time referred to stationary power could be
obtained for one farthing per horse-power per hour, while locomotive
power cost more than one penny per indicated horse-power per hour, the
cost of the locomotive power being more than four times that of the
stationary power. On a level line at a speed of 60 miles per hour, for
each horse-power usefully employed, a locomotive, in consequence of its
own dead weight and the friction of its machinery, is obliged to expend
more than one and a half horse-power; in this case, therefore, the
useful work done costs nearly seven times as much as if it had been
performed by a stationary engine. Again, on so moderate an ascent as one
in 75, for each horse-power usefully employed, the locomotive has to
expend at 40 miles per hour more than two horse-power, and at 60 miles
per hour three horse-power; so that the useful work done costs in the
one case nearly ten times, in the other thirteen times, as much as if
it had been performed by a stationary engine.
This great advantage of stationary over locomotive power was a
sufficient justification for introducing a system which promised to
realise it to any considerable extent; although many difficulties might
have to be encountered.
As has been already stated, Mr. Brunel had satisfied himself that the
Atmospheric System was theoretically economical, and that its trial at
Dalkey had shown that it was practically free from mechanical
objections. Mr. Stephenson, indeed, had admitted that the mechanical
details had been brought to a remarkable degree of perfection; but this
admission was not any qualification of the radical difference of opinion
which existed between him and Mr. Brunel, to which Mr. Brunel drew
attention in his report of August 1844.
The subsequent abandonment of the Atmospheric System led many to believe
that Mr. Brunel had been rash in rejecting the detailed investigations
and conclusions of Mr. Stephenson, and that the adverse conclusions
which Mr. Brunel had refused to entertain were subsequently established.
But, in fact, the failure of the Atmospheric System was due to failure
in some of its mechanical details, and was not due to those inherent
defects in its principle which Mr. Stephenson in his report considered
that his experimental data had established.
Mr. Brunel’s opinions were again brought prominently into notice in the
evidence given by him before a Select Committee of the House of Commons,
which was appointed in the Session of 1845, in consequence of the number
of projected lines which it was proposed to work by the Atmospheric
System.
The following letter, written by Mr. Brunel to one of the members of the
Committee, explains what he considered to be his position at this
time:--
April 3, 1845.
I am summoned to attend your Committee on Friday, and as it is
known that I have expressed opinions favourable to the Atmospheric
System, and that I am actually applying it upon a line of some
length, it would be considered an absurd affectation, and would,
moreover, be useless to attempt, to avoid giving evidence when so
called upon; but I am a most unwilling witness. I think it rather
hard upon a professional man, who wishes to be cautious and
prudent, that he should be called upon to express general opinions,
which, if written even in the most studied and careful language,
cannot be so worded as to be applicable to every case that may
hereafter arise, or to be proof against the unfair and unscrupulous
attack of the paid writers on these controversies. I mention these
difficulties, which I feel that you may make some allowances for,
if my feelings should appear in my evidence, or if that evidence
should appear to fall very short of the opinions I am known to
entertain, and which I must entertain to induce me to apply the
system extensively, as I am doing. I find it difficult to define
the points upon which it would be desirable to examine engineering
witnesses, and I really believe that, entering freshly upon the
subject and feeling as one of the public, you are more likely to
elicit the useful points than one who, like myself, has been
turning his whole attention (lately, at least) solely to the
mechanical construction. However, I enclose a copy of a letter I
addressed to a party interested in the patent, which refers to my
opinions on the several points--opinions, however, expressed
without that caution to which I referred as so necessary.
(_Enclosure._)
March 31, 1845.
I object very much to giving evidence upon the abstract point of
the applicability of a particular system, and thus furnishing
general opinions which others are to apply as they may choose to
particular cases; and if I could, I would refuse to give evidence
at all before the present Committee, whatever might be the
consequence to the promoters of the Atmospheric System.
Circumstances, however, render such a refusal impossible; but I am
equally anxious not to be drawn into becoming an advocate of a
system.
When I gave evidence last year,[67] although it was then very much
against my inclination, it was in support of a particular case; and
it was only incidentally that my opinion was advanced as to a
system. The evidence is now avowedly sought in support of a system,
and I do not, as I before stated, intend to become an advocate of
this or any other system. I mention these my views to prevent
disappointment. If the following facts and opinions are likely to
be of use to the Committee, I can give evidence on them.
I made experiments upon the portion of railway laid on Wormwood
Scrubs. These experiments were made for my own private
satisfaction, and not made public in any way.
They satisfied me of the mechanical practicability of the system.
In 1843 and 1844 I made several experiments upon the Dalkey
railway.
The result of my observations and of those experiments is an
opinion that the mechanical difficulties attending the application
of this system may be overcome, and the whole as a machine made to
work in a very perfect manner; that is, as a mechanical power for
locomotion it will generally, but not in every case, be more
economical than what is strictly called locomotive power, that high
speeds may be more easily attained, that, from the absence of the
locomotive engine, the rails may be constructed and maintained in
more perfect order, and as a consequence the carriages may be
constructed and worked in a more perfect manner, and so as to run
more smoothly, and that in all respects the travelling may be
rendered more rapid, more luxurious, and more safe. As regards the
last, viz. safety, collisions may be rendered altogether
impossible, or most remotely possible; while all other sources of
danger, now very small, may be almost entirely removed by the
increased perfection of the rails.
As regards first cost, a single line may be made to answer all the
purposes of a double locomotive line for most railways, except main
lines in immediate connection with the metropolis, or forming trunk
lines for others with important branches not under the same
control; and a single Atmospheric line will generally cost as
little, often less, including the working power, than a double
locomotive line without the engines. I am now constructing a line
of 52 miles in length entirely for the Atmospheric System. I
already see many advantages to be attained in the setting out and
constructing of a railway, if originally designed for this system;
the principal advantages can only be attained, and, above all, the
principal difficulties in the system can only be properly provided
against, where the line is originally designed for the system; the
choice of gradients and curves and levels, the position, and, above
all, the arrangements of stations, will generally be totally
different in the two systems, and the difficulties to be avoided
will equally differ.
It is unnecessary to give any extracts from Mr. Brunel’s evidence,[68]
as it only repeats the opinions and calculations embodied in his report
of August 1844.
The Committee, while they allowed that experience could alone determine
under what circumstances of traffic or of country the preference to the
Atmospheric or the Locomotive System should be given, reported very
strongly in favour of the general merits of the Atmospheric System.
As soon as it had been decided that the South Devon was to be
constructed as an Atmospheric line, the dimensions of the cuttings,
embankments, and tunnels were arranged for a single line, except on the
long incline west of Totness, and on that east of Plympton. In the
approaches to the principal summits the gradients were made somewhat
steeper, so as to reduce the excavations.
In December 1844, Mr. Brunel prepared a specification and drawing of a
steam-engine and vacuum pump, and a copy was sent to the most eminent
engine-builders, together with a letter inviting tenders for six pairs
of engines. The letter concluded as follows:--
Any party whose tenders may be accepted, shall, if required,
furnish forthwith a more detailed drawing and specification of the
engines as they propose to furnish them; the specification and
drawing now sent being expressly made very general, in order that
each manufacturer may, so far as is consistent with the general
requisites and conditions, adopt his own methods of construction,
or use any existing patterns.
The economical character of the engines which Mr. Brunel desired to
obtain is sufficiently indicated by the requirement that they were to be
high-pressure condensing engines, fitted with double-seated expansion
valves, and having boilers proved to 100 lbs. per square inch, and
guaranteed to work with safety valves loaded to 40 lbs. per square inch.
The tenders accepted were those of Messrs. Boulton and Watt, Messrs.
Rennie, and Messrs. Maudslay and Field.
Mr. Brunel left it to the contractors to prepare their designs without
any interference on his part, deeming it best to rely on their
unfettered judgment.
The task of manufacturing and fitting the cast-iron tube was one of some
difficulty, the longitudinal slit allowing of considerable distortion in
the casting. This work was undertaken by Mr. George Hennett, by the aid
of a set of very effective tools devised by Mr. T. R. Guppy.
The tubes were supplied at the rate of one mile per week, and by the
middle of 1846 nearly the whole line was laid to Newton, and the valve
was ready to be fixed.
In the autumn of 1846, Mr. Joseph Samuda went to Dawlish, taking with
him a staff of assistants trained in the working of the system at
Croydon; and every effort was made to advance the completion of the
engines and the other parts of the apparatus.
Owing, however, to vexatious delays in the erection of the engine-houses
and engines, it was not until the commencement of 1847 that a
piston-carriage was able to traverse the first six miles out of Exeter.
And, though repeated experimental trains continued to be run, no
passengers had been conveyed by Atmospheric trains prior to the general
meeting of the shareholders, at the end of August. Mr. Brunel’s report
on this occasion was as follows:--
August 27, 1847.
It is a subject of great regret, and to no one more than to myself,
that we have as yet been unable to open any portion of the line to
the public with the Atmospheric apparatus, although a considerable
distance has for some months been in a state to admit of frequent
experiments being made upon it. This delay has arisen principally,
if not entirely, in that part of the whole system which it might
have been expected would have been the least exposed to it--namely,
the construction and completion of the steam-engines.
It is due to Mr. Samuda that I should say that, so far as regards
the mere pipe and valve, and other details which may be said to
constitute the Atmospheric apparatus, we might long since have
commenced. But the engines, although designed without any
interference with their plans, and furnished by the best makers of
the country, and although differing so slightly from the ordinary
construction of steam-engines, have proved sources of continued and
most vexatious delays, both in the unexpected length of time
occupied originally in their erection, and in subsequent correction
of defects in minor parts. While the engines were imperfect, it
would not only have been unwise to have commenced working the line,
even had it been practicable, but the frequent interruptions to the
continuous working of all the engines rendered it impossible to
complete and test the different portions of the Atmospheric
apparatus. There are still some defects to be remedied in one or
two of the engines, and I am using every endeavour, by persuasion
and by every other means in my power, to urge on the manufacturers
in their work of completion. Within the last week or two only have
we been able to work at all continuously between Exeter and
Teignmouth, so as to have the opportunity of trying the different
parts, and getting the various details requisite for actually
working trains tested and brought to sufficient perfection to
ensure efficiency and regularity.
Since the beginning of last week, however, four trains per day have
been run regularly, stopping at the stations, and keeping their
time as if working for traffic. The tube and valve appear in good
order, and the whole has worked well, but the running in this
manner can alone show the deficiencies which may still exist in the
details necessary for stopping, and starting quickly from the
stations, and all the other minor operations incidental to working
the traffic in the ordinary course; and, until all these
arrangements are completed, and the engines in more perfect order,
I think it would be much better to defer at least the substitution
of the Atmospheric for the locomotive working. Trains, in addition
to those now running may perhaps be advantageously worked for the
public, after a further short continuance of the present
practising.
The two engines completing the number to Newton are nearly ready
for trial, and it is to be presumed that, after the experience of
the past, the makers will be enabled to put them at once into an
efficient state.
The delays and difficulties attending the bringing into operation
the Atmospheric System upon this portion of the railway have been
beyond all anticipation, and beyond what any previous experience
would have justified anybody in anticipating. The difficulties have
all been seriously aggravated by the necessity (consequent,
certainly, upon the original delays) of working the line with
locomotives during the construction and completion of the
Atmospheric apparatus. Not only has the constant occupation of the
line interfered with the progress of the work, but it has been
necessary to devise all the arrangements so as to admit stations,
sidings, and line being worked either by locomotive or by
Atmospheric in succession, or even at the same time.
These difficulties, added to those always consequent upon the
introduction of any new system, have been most wearying and
incessant, and I am not surprised that the public and the
proprietors should have been impatient. I trust the ultimate result
will remove any grounds for disappointment.
The stress of personal anxiety and personal fatigue, experienced by Mr.
Brunel and by all who were engaged in the work, was very severe, and
continued so to the end. Not only was the progress in the completion of
the work slow, but in spite of every exertion the results were
incessantly marred by unfortunate contingencies which involved further
delay, discouragement, and expenditure. Moreover, the reaction which
followed the railway mania had set in; calls were ill responded to, and
great difficulty was experienced in raising the money requisite for the
completion of the line.
Under these circumstances it was resolved, on September 1, not to incur
any new expenses in relation to the Atmospheric System beyond Totness,
and to limit any expenditure already contracted for, until its working
between Exeter and Totness had been fairly tried, except to provide
assistant power up the two inclines.
On September 8 the Atmospheric trains began to take their share in the
passenger duty of the line, four trains running each way daily; and,
except when occasional mishaps caused delay, the new mode of traction
was almost universally approved of. The motion of the train, relieved of
the impulsive action of the locomotive, was singularly smooth and
agreeable; and the passengers were freed from the annoyance of coke dust
and the sulphureous smell from the engine chimney.
In other respects the record of progress is but a chequered one, and
exhibits, in spite of great and able efforts and brightening intervals
of occasional improvement, indications of growing difficulties deepening
into ultimate defeat.
In examining the chronicle of events which correspondence and memoranda
supply, it is inevitable that references to failure and disaster should
be found relatively in far greater abundance than records of success;
and this for the simple reason that there was at that time great use in
taking note of the unfavourable incidents that occurred, almost none in
mentioning successful work.
There is therefore some danger of falling into a mood of unjust
depreciation, such as Mr. Brunel had in energetic terms urged the
Directors to guard themselves against. He protested against their
requiring (as they once intended to do)--
continuous and detailed reports--if true and honest, of course
containing nothing but accounts of mishaps--of a system which (he
says) we are struggling to render perfect. Why, a daily account of
our locomotive mishaps would ruin the locomotive system, if it were
new! I will undertake to say that the mishaps of yesterday or
to-day on the Great Western Railway were as great as that of
Tuesday on the South Devon.
The Atmospheric System was vaguely credited with every delay which a
train had experienced in any part of its journey; though, in point of
fact, a large proportion of these delays was really chargeable to that
part of the journey which was performed with locomotives. It often
happened that time thus lost was made up on the Atmospheric part of the
line, as is shown by a record of the working, which is still extant. In
the week, September 20-25, 1847, it appears that the Atmospheric trains
are chargeable with a delay of 28 minutes in all; while delays due to
the late arrival of the locomotive trains, amounting in all to 62
minutes, were made up by the extra speed attainable on the Atmospheric
part of the line.
Not unfrequently, however, casualties occurred; due indeed to remediable
causes, but yet of discouraging aspect in themselves, and deriving
additional weight from the manner in which they reacted on the cost of
working. Such, for instance, were the frequent and occasionally very
serious breakages in essential parts of the pumping-engines. Again, the
cupped leathers of the travelling-piston, which made it air-tight, were
often destroyed while it was passing the various inlet and outlet
valves. Improvements in the valves were introduced to meet this
difficulty; but the remedy could not be applied at once throughout the
line, and much inconvenience was thus experienced, and a considerable
expense incurred. Another source of inconvenience was the water which at
times accumulated within the tube.
* * * * *
In many respects the results which had been calculated on were realised,
and the new arrangements necessary to the working of the system were
successfully brought into operation.
The speed of the trains corresponded fully with the degree of vacuum
obtained; that is to say, the train resistances proved to be what had
been anticipated.[69]
After the trial of a great variety of air-pump valves, a form was
adopted which was found to answer exceedingly well.[70]
In the Atmospheric tube, the system of self-acting inlet and outlet
valves, by which the piston was enabled to leave the tube on approaching
a station and enter it again on recommencing its journey, were, on the
whole, successfully adapted to their duty.
Again, an arrangement for starting the train rapidly from the station,
without the help of horses or of locomotives, had been brought
practically into operation. This arrangement consisted of a short
auxiliary vacuum tube containing a piston which could be connected with
the train by means of a tow-rope, and thus draw it along till the
piston of the piston carriage entered the main Atmospheric tube. Some
accidents at first occurred in using this apparatus, but its defects
were after a time removed; and it is hardly to be doubted that the
various minor difficulties of the Atmospheric System could soon have
been effectually mastered.
* * * * *
It now remains to show how it was that, in spite of much that was
hopeful, a vigorously sustained contest ended in defeat, instead of
being prolonged into victory.
In working the Atmospheric System on the South Devon Railway grave
difficulties were throughout encountered, for which to the last only
imperfect remedies could be found.
As regards the power consumed, the engines of each pumping station
worked up to about 236 indicated horse-power, and their regulated duty
for each train, including the anticipatory pumping, was equivalent to
5·5 minutes of work for every mile of the length of tube they had to
exhaust. As the running speed averaged 40 miles per hour, or a mile in
1·5 minutes, the 236 horse-power during the 5·5 minutes of pumping must
be regarded as equivalent to 865 horse-power during the actual passage
of the train. Now, making full allowance for piston friction and extra
friction on curves, for the power expended in getting up speed, for the
excess of air-pump resistance due to the changes of temperature
experienced by the air under exhaustion, and even for the very large
actual amount of friction in the engines employed, the work done should
have been represented by an expenditure of 240 horse-power during the
passage of the train. If to this is added an allowance for leakage, such
as the experiments at Dalkey indicated would be amply sufficient with
the longitudinal valve in good condition, it may be said that Mr.
Brunel had a right to expect that the duty would be performed with an
expenditure of 300 horse-power; whereas it actually required 865
horse-power, or nearly three times the amount.
The explanation of this waste is simple.
Serious and unexpected causes of failure developed themselves in the
longitudinal valve, and led to an excessive amount of leakage. A great
part of the normal duty of the engines was, as has been stated, to
exhaust the tube previous to the entry of the train; and when, owing to
leakage, the amount of air to be so pumped out was greatly increased, it
became necessary that the operation should be commenced much earlier.
There was thus a longer time during which the leakage could take place,
and a still greater amount of air to be pumped out. It therefore
followed that a large increase of leakage involved waste of power in an
enormously increased proportion.
The length of time occupied by the anticipatory pumping was often
increased by the difficulty of arranging proper telegraphic
communication on the South Devon Railway, and by the absence of it on
the Bristol and Exeter Railway. The Electric Telegraph was in its
infancy, and though Mr. Brunel had been the first to apply it in
connection with railways, namely, between London and Slough on the Great
Western Railway in the year 1839, it was not brought into perfect
working order on the South Devon Railway till the Atmospheric System was
on the point of being abandoned. The result of the defects in the
telegraph was that, when a train was late, warning was not received at
the several engine-houses;[71] and thus, when this was the case, the
pumping-engines which had been started at the right interval of time
before the train was due, had to be kept at work for a needlessly long
period pumping out the air, which was all the while leaking in through
the deteriorated valve. This inefficiency of the telegraphic apparatus
would have been of trifling importance but for the defects of the valve.
Had the valve been as perfect as it was expected to be, the vacuum,
after it had been formed, could have been maintained by an expenditure
of power very moderate in comparison with that which was actually
required.
As regards the relative cost of the power consumed, it appears that,
owing to imperfections in the engines, their expenditure of fuel per
indicated horse-power was more than double that of the best of the
Cornish pumping-engines, to which they were analogous; while the cost of
working was more than three times as great.
The defects in the engines were for the most part such as might have
been remedied; and this would have been done, had not the excessive duty
imposed on them by the leakage of the longitudinal valve prevented their
being stopped for repairs and alterations. In this way the defects of
the different parts of the apparatus mutually aggravated each other.
It appears then that, chiefly owing to the defective longitudinal valve,
the engines were expending nearly three times the power which they
should have done for a given tractive duty, according to previous
experience, and the results obtained on the Dalkey line, and that they
cost per horse-power at least three times as much as was expected.
The cost of traction, nearly nine times as much as had been calculated
on, was between two and a half and three times what it would have been
with locomotive power; and this was on a level part of the line, where
the comparative advantages of the Atmospheric System were not exhibited
as they would have been in the part which had steep gradients.
The imperfections of the longitudinal valve have now to be described. By
its condition the Atmospheric System had to stand or fall. With an
efficient valve, the defects of the other parts of the apparatus would
have been of minor importance, and time would have been given for
remedying them. When the leakage became considerable, the defects of the
telegraph and the defects of the engines alike assumed a formidable
aspect.
The failure of the valve was due, partly to the composition which was
used to seal the joint where it opened, and partly to the material of
which the valve consisted. The difficulty of obtaining a suitable
composition was the first which had to be encountered. On the South
Devon a lime soap was eventually found to answer the purpose well. Its
surface, however, from exposure to light and air, formed into a hard
skin; and to remedy this a thinner and more fluid material, a compound
of cod-oil and soap, was laid on to keep it soft. This answered
satisfactorily, but it required frequent renewal, as it was apt to be
drawn into the tube by the rush of air when the valve was opened. The
renewal of the various compositions, and the careful examination and
repair which the valve constantly required, was a cause of great anxiety
and expense.
But in the materials of the valve lay the source of the more serious
difficulty.
The ready affinity of leather for oil and grease, and its suppleness and
closeness of grain when saturated with substances of that nature, had
long been known and utilised. It had not been anticipated how readily,
with air-pressure on one side and a partial vacuum on the other, the
oily matters with which the leather was charged would escape from it,
especially in the presence of water. Although, while the leather was
saturated with water, the valve was remarkably air-tight; when frost
supervened the water became frozen, and gave a fatal stubbornness of
texture, which rendered the valve incapable of closing properly. Again,
in long-continued drought the leather became intractable from its
dryness; and the stiffening, whether from frost or drought, rendered it
liable to be torn. An immediate application of seal-oil penetrated the
leather, and relaxed its stiffness; but the remedy often could not be
applied in time, and, moreover, was expensive.
A still more grave defect was all the while becoming matured, and was
undermining every hope that a suitable dressing could be discovered, and
that the longitudinal valve might be made perfect.
Under the joint action of water in the leather, and of the affinity of
iron for tannin--and on the enduring presence of tannin within its
texture the consistency of leather depends--a destructive decomposition
had long been at work; the oxide, established in the iron plates of the
valve by continued contact with damp leather, had been steadily
abstracting the tannin; thus the leather had become converted into an
ink-stained and comparatively decomposed tissue. Large portions of it
became torn, and incurably pervious to air.
It was not until early in June 1848 that Mr. Brunel discovered the
condition which the valve had assumed. He then instituted a careful
examination throughout the line, and the extent of the disorder was
realised.
The state of things which existed when this discovery was made in effect
involved the renewal of the valve the whole distance from Exeter to
Newton; so that, as the cost of the valve was 1,160_l._ per mile, an
immediate outlay of some 25,000_l._ became essential to the maintenance
of the system, and this at the time when the real difficulties of the
valve question had become most apparent. By galvanising the iron plates
of the valve the mutually destructive action of the iron and the leather
might have been prevented; but a remedy was also required for the other
serious defect which leather, as the material of the valve, was found to
exhibit, namely, its tendency to become permeable to air after
long-continued use under air-pressure, owing to the inward escape of the
material with which it had been dressed.
These difficulties were not only such as had not been anticipated, but
such as no one was justified in anticipating.
* * * * *
It now became necessary for Mr. Brunel to consider what course, under
the circumstances, it was most advisable for the Company to adopt.
A Committee of the Board was appointed to examine the whole question;
and, at their desire, Mr. Brunel made a report upon it, which was as
follows:--
August 19, 1848.
You have called upon me to report to you upon the present state of
the Atmospheric apparatus, and particularly upon the circumstances
connected with the partial destruction of the longitudinal valve
which has lately occurred, and the probability of remedying this
serious defect, and of keeping the valve in repair and in good
working order.
Such a report involves necessarily the consideration of the whole
question of our experience of the working of the Atmospheric
System; because, to arrive at any clear appreciation of the present
state of the apparatus, I must refer to the circumstances which
have affected our working up to the present time, and particularly
to the several difficulties which we have had to encounter and
their effects.
The first difficulty, and one which was as unexpected as it was
serious, was in the working of our stationary engines. Upon the
efficiency of these machines must of course ultimately depend the
economy and efficiency of the working of the whole system, however
perfect in itself might be the Atmospheric apparatus. Accordingly,
great precautions were taken--precautions which I still think such
as to justify the expectation that we should secure the best
engines that could be made.
The three first manufacturers of the day were employed--Messrs.
Maudslay (who had had some experience in this particular branch,
having made the engines for the Croydon railway), Messrs. Boulton
and Watts, and Messrs. Rennie. They prepared their own designs; and
I know that they each bestowed much thought in the preparation of
these designs, and took considerable interest in the results.
Mr. Samuda, a man of considerable mechanical abilities, having all
the experience that could be had upon the subject, and deeply
interested in the success of the engines, was also employed to
superintend their manufacture.
Notwithstanding all these precautions, notwithstanding excellent
workmanship, these engines have not, on the whole, proved
successful; none of them have as yet worked very economically, and
some are very extravagant in the consumption of fuel, burning
nearly double the quantity of others, while the average is very
considerably more than it ought to be.
The apparent causes of this excess are various in the different
engines, but all resulting more or less apparently from the want of
experience in this particular application of power, and from the
circumstance of the form of the engines being somewhat novel, and
involving slight differences in the proportion and arrangement of
the parts; and the consumption of steam being greater than was
calculated upon, it has been obtained by a more wasteful
expenditure of fuel, and the evil has been aggravated.
The difficulty of remedying this state of things has been increased
by the consequence of defects in the Atmospheric apparatus, which,
causing a much greater demand upon the working of the engines, has
delayed, or has entirely prevented, our throwing an engine out of
work, to introduce the requisite improvements.
Still, so far as this defect in the engines is concerned, there is
no doubt that it is susceptible of considerable, if not complete
remedy, and that a reduction of one-third may be effected in the
consumption of fuel.
In the Atmospheric apparatus itself our difficulties have been more
numerous.
We have suffered from extreme cold, particularly when it followed
quickly upon wet.
We have suffered from extreme heat, and also from heavy falls of
rain. These difficulties have in turn been encountered and
gradually overcome, and I think the effects of all these causes
upon a valve in good condition may now be obviated, if not
entirely, yet so much so as to render their operation unimportant.
The same remedy applies to all three--keeping the leather of the
valve oiled and varnished, and rendering it impervious to the
water, which otherwise soaks through it in wet weather, or which
freezes in it in cold, rendering it too stiff to shut down; and the
same precaution prevents the leather being dried up and shrivelled
by the heat; for this, and not the melting of the composition, is
the principal inconvenience resulting from heat. A little water
spread on the valve from a tank in the piston-carriage has also
been found to be useful in very dry weather, showing that the
dryness, and not the heat, was the cause of leakage; but a new
difficulty has arisen, and a new defect has been discovered, one
much more serious in its extent and its possible consequences, and
one which renders the operation of each of the previously mentioned
causes of difficulty much more powerful and mischievous.
Within the last few months, but more particularly during the dry
weather of last May and June, a considerable extent of longitudinal
valve failed by the tearing of the leather, at the joints between
the plates; the leather first partially cracked at these points,
which causes a considerable leakage, particularly in dry weather;
after a time it tears completely through, and that part of the
valve is destroyed, and requires to be replaced.
A considerable extent has thus been replaced, but the whole of the
valve is more or less defective from this cause; the amount of
leakage is considerable, and the working altogether inefficient. I
have examined carefully portions of the valve that have been
removed, and I find that at the part which has given way the
texture of the leather seems to be destroyed--it is black, and has
evidently been acted upon by the iron of the plates.
Upon some parts of the line the injury seems to be more general
than upon others; but it is very difficult to examine the valve in
place, so as to form any correct opinion of the extent of the evil.
As regards the cause of this defect, Mr. Samuda, who under his
contract is at present liable for the repair of the valve, urges
that the valve was kept for a length of time in cases after it was
delivered to the Company, and that, exposed to damp, and the oil
in the leather not being renewed on the surface, the iron may have
rusted, and the leather have been injured; and he refers to
instances lately observed, in which valves taken out of the top of
a case which had been exposed to wet do show similar signs of
injury.
Supposing, however, this assumption to be correct, it would not
seem to affect the question of his liability. He suggests also, as
a cause, that the valve remained for a length of time in place
without been used and even worked over by locomotive engines, which
prevented its being properly oiled and attended to; that the evil
has been aggravated by an attempt to reduce too much the use of oil
to the leather; and, lastly, that the piston-gear has been allowed
to get out of adjustment, so that the leather of the valve has been
strained.
I shall not, however, here enter into the discussion of this
question of liability, but confine myself to the consideration of
the evil, and the possibility of remedying it.
Of the extent of the evil, for the reason I have given, it is
impossible to form any accurate opinion; it is impossible,
therefore, to say that it does not extend more or less over the
whole distance, excepting, of course, that which has been already
replaced. That which is injured cannot be repaired in place, but
must be removed, and the remedy can only be applied in the new
valve.
It is quite possible that a valve made in the same manner as the
present, if properly attended to from the first, and with our
present experience, might not be subject to this destruction, and
Mr. Samuda states that such is the case at Dalkey; but I do not
think that I could rely upon this result. By painting, but, better
still, by zincing or galvanising the iron plates, and making them
overlap a short distance, both the chemical and the mechanical
action of the plate upon the leather appears to be prevented, and I
believe, therefore, that this evil may be remedied at a small
increased cost in any new or repaired valve that might be laid
down: but of the existing valve I can say no more than I have done.
It is not now in good working condition, and I see no immediate
prospect of its being rendered so.
From the foregoing observations, it will be evident that I cannot
consider the result of our experience of the working between Exeter
and Newton such as to induce one to recommend the extension of the
system.
I believe that if the longitudinal valve were restored, the working
expenses might be immensely reduced; that the quantity of fuel
consumed which is the great item of expense, may be diminished by
one-third; that the price of the fuel, which now costs 18s. per ton
at the engine-houses, ought to be reduced at least 12 per cent.;
and that the total cost may thus be brought down to a moderate
amount, such as I had originally calculated upon. But the cost of
construction has far exceeded our expectations, and the
difficulties of working a system so totally different from that to
which everybody, traveller as well as workmen, is accustomed, have
proved too great; and therefore, although, no doubt, after some
further trial, great reductions may be effected in the cost of
working the portion now laid, I cannot anticipate the possibility
of any inducement to continue the system beyond Newton.
With respect to the future working of the apparatus between Exeter
and Newton, I feel in great difficulty as to expressing any
opinion, seeing that a very large expense has been incurred, and
believing, as I do, that the cost of working may be so very much
reduced; but that reduction can only be effected by the almost
entire renewal of the valve, and by some expenditure in the
engines. And unless Mr. Samuda or the patentees undertake the
first, and extend considerably the period during which they would
maintain it in repair, and unless they can offer some guarantee for
the efficiency of that valve, I fear that the Company would not be
justified in taking that upon themselves, or incurring the expense
attending the alteration of the engines.
I believe that for the inclined planes, as an assistant power, the
apparatus will be found applicable and efficient; and as the
engines and the pipes are nearly ready at Dainton, it may be found
desirable to try it there, provided a satisfactory arrangement can
be entered into for the maintenance and efficiency of the valve.
I have not referred to our great disappointment in not obtaining
the assistance of the telegraph in the working of the engines, and
the greatly increased consumption of coal consequent upon the
working the engines unnecessarily, because this evil is now nearly
removed; but some further reductions may still be made by using the
telegraph by night as well as day, which has not yet been in our
power to do, but which I trust will be commenced this week.
The Committee to whom this report was made, and who had been also in
constant communication with Mr. Brunel, placed the result of their
investigation before the Board. The Directors, after carefully
considering the information given them, reported as follows:--
Your Directors, without pronouncing any judgment as to the ultimate
success of the Atmospheric System, and while they are prepared to
afford to the patentees and other parties interested in it the use
of their machinery for continuing their own experiments, have
arrived at the conclusion, with the entire concurrence and on the
recommendation of Mr. Brunel, that it is expedient for them to
suspend the use of the Atmospheric System until the same shall be
made efficient at the expense of the patentees and Mr. Samuda.
At the meeting in August, the proprietors adopted the Directors’ report,
and the line was worked throughout by locomotives on and after September
9.
In the following November Mr. Thomas Gill, the chairman of the Board of
Directors, published an ‘Address to the Proprietors,’ in which he
strongly deprecated the abandonment of the Atmospheric System, and
proposed that the Company should embark on a further experiment. Mr.
Gill’s pamphlet was referred to three of the Directors, Mr. Thomas
Woollcombe, Mr. Charles Russell, and Mr. James Wentworth Buller. With
Mr. Brunel’s assistance, and to a great extent from memoranda written by
him, they prepared a statement which went very fully into all the points
raised by Mr. Gill.
After combating Mr. Gill’s propositions, they observe:--
Of the two men who are most deeply concerned in the further trial
of any reasonable experiment to perfect the Atmospheric System, we
find that one, Mr. Brunel, disapproves of the proposal for the
purpose as insufficient and unsatisfactory; the other, Mr. Samuda,
had not sufficient confidence in the result, or in Mr. Gill’s
estimates for its accomplishment, to offer the only security which
would justify the Company in endeavouring to effect it.
In conclusion they express an opinion that the suspension of the
Atmospheric System in the previous September was a prudent and necessary
step, and that nothing had since occurred to justify its resumption.
The proprietors adopted the view taken by the Committee, and no further
attempt was made to work the railway on the Atmospheric System.
Under these circumstances, it cannot be a matter of surprise that Mr.
Brunel was much censured for having advised the South Devon Railway
Company to work their line on the Atmospheric System.
The reasons which led him to recommend the use of the Atmospheric System
on the South Devon, and the causes of its failure, have been very fully
described, and it has been also shown that the most important of these
were the defects of the pumping-engines, and the deterioration of the
longitudinal valve.
When the formidable character of these difficulties had fully declared
itself, the South Devon Railway Company were not in a position to spend
any more money upon a system which, as the event had proved, was, in one
of its most important details, still in the experimental stage.
There can be no doubt that the abandonment of the Atmospheric System was
the wisest step which, under the circumstances, could be adopted; and it
was recommended to the Directors by Mr. Brunel with a simple and
self-sacrificing disregard of every consideration except that which was
always paramount with him, the interests of those by whom he was
employed.[72]
NOTE (p. 143).
_Comparison of Stationary and Locomotive Power._
In order clearly to set forth the reasons which justify the statement
made by Mr. Brunel,[73] that stationary power if freed from the weight
and friction of any medium of communication, such as a rope, must be
cheaper than locomotive power, it is desirable to consider, (1) the
waste of power which arises from the locomotive having to move itself as
well as the train; and (2) the excess of cost at which a given power was
supplied by a locomotive, as compared with that at which it could have
been supplied by a stationary engine.
On the first point, the best information can be obtained from
experiments made by Mr. Daniel Gooch during the gauge controversy. The
results are very suitable for use in the present investigation, as the
South Devon was to be a broad-gauge railway. Moreover, as the
broad-gauge engine with which these experiments were tried was one of a
class more powerful for their weight not only than the contemporary
narrow-gauge engine, but also than the engines Mr. Brunel had experience
of when he wrote his report three years previously, the results may be
considered to represent very favourably the then existing case for the
locomotives.
The engine employed in the experiments weighed, with its tender, about
fifty tons. The maximum power it was capable of delivering by the
pressure of steam in its cylinders was represented as a tractive force
of 4,900 lbs. at a speed of 60 miles an hour, equivalent to 784
indicated horse-power; and at 40 miles an hour 5,200 lbs., equivalent to
555 indicated horse-power.
It is next to be considered how this power would, when running at the
speeds mentioned, be employed in overcoming the elements of resistance.
These are:--
(1) The working friction of the machinery.
(2) The rolling resistance of the engine and tender.
(3) The air resistance due to the engine frontage.
(4) The rolling resistance of the train.
(5) The air resistance on the portion of the train unprotected by
the tender.
(6) The resistance due to gradient.
The following symbols and quantities may be conveniently made
use of to denote the various terms of the equation between force
and resistance.
Total available tractive force in lbs. F
Weight of engine and tender (superfluous load) in tons 50
Weight of train (useful load) in tons W
The sum of the resistances of machinery, rolling resistance,
and air resistance of engine and tender R
Rolling resistance of train in lbs. per ton K
Gradient G
Speed in miles per hour V
Resistance of air (according to the received empirical formula)
1
= --- (frontage area) × V^{2}
400
Frontage area of train in square feet 63
Frontage area of portion of train unprotected by the tender,
in square feet 24
For a locomotive train therefore
24
F = R + WK + --- V^{2} + (50 + W) 2240 G.
400
For a system that dispenses with the locomotive
63
Tractive force = WK + --- V^{2} + W 2240 G.
400
Therefore
W (K + 2240 G) + ·1575 V^{2}
= the useful tractive force, and
R + 112000 G - ·0975 V^{2}
= the tractive force wasted by the use of the locomotive.
Therefore
F={R + 112000 G-·0975 V^{2}} + {W (K + 2240 G) +·1575 V^{2}}
and the useful load
(F- R - 112000 G - ·06 V^{2})
W = -----------------------------
K + 2240 G.
The values which Mr. Gooch’s experiments give for the two selected
speeds are as follows[74]:--
+---------------+---------+-----------------+----------+
|Miles per Hour | R (lbs.)| K (lbs. per ton)| F (lbs.) |
+---------------+---------+-----------------+----------+
| 40 | 1500 | 12·5 | 5200 |
| 60 | 2100 | 18·6 | 4900 |
+---------------+---------+-----------------+----------+
Using these values, the results in the following table are obtained,
being the conditions appropriate to the two speeds at successive
ascending gradients:--
+------+---------+-------+-------+------+-------+------+------+-----------+
|Miles |Ascending|Useful |Super- | Gross|Useful |Waste |Gross |Ratio of |
|per |Gradient |Load | fluous| |Load |Horse-|Horse-|Horse-power|
|Hour | |in tons|Load in| |in tons| power| power|Waste to |
| | | | tons | | | | |Useful |
| | | | | | | | |Horse-power|
+------+---------+-------+-------+------+-------+------+------+-----------+
| {| 0 | 288 | 50 | 338 | 411 | 144 | 555 | ·35 |
| {| 1/200 | 128 | 50 | 178 | 352 | 203 | 555 | ·58 |
| {| 1/100 | 71 | 50 | 121 | 292 | 263 | 555 | ·90 |
| 40 {| 1/75 | 50 | 50 | 100 | 252 | 303 | 555 | 1·20 |
| {| 1/50 | 23·8 | 50 | 73·8| 173 | 382 | 555 | 2·21 |
| {| 1/40 | 11·7 | 50 | 61·7| 113 | 442 | 555 | 3·91 |
| {| 1/36·3 | 7 | 50 | 57 | 82 | 473 | 555 | 5·77 |
| | | | | | | | | |
| {| 0 | 139 | 50 | 189 | 504 | 280 | 784 | ·56 |
| {| 1/200 | 68 | 50 | 118 | 415 | 369 | 784 | ·89 |
| {| 1/100 | 35·7 | 50 | 85·7| 325 | 459 | 784 | 1·41 |
|60 {| 1/75 | 22·5 | 50 | 72·5| 265 | 519 | 784 | 1·96 |
| {| 1/52·3 | 7 | 50 | 57 | 160 | 624 | 784 | 3·90 |
+------+---------+-------+-------+------+-------+------+------+-----------+
Thus, on a level line, the engine, working up to 555 horse-power, could
just draw 288 tons of train at the rate of 40 miles per hour, wasting on
its own resistance only one-third of the power usefully employed on the
train; but when the speed was increased to 60 miles per hour, it could
not, though working up to 784 horse-power, draw more than 139 tons of
train, wasting on its own resistance more than half the power usefully
employed on the train. And again, at 40 miles per hour, though, as just
stated, it could draw on the level 288 tons, it could only draw 24 tons
of useful load at that speed up 1 in 50; while at 60 miles per hour,
though it could draw, as stated, 139 tons of train on the level, it
could only draw 23 tons of useful load up 1 in 75; and at the respective
speeds of 40 and 60 miles per hour, it could only take one carriage (7
tons) up the respective gradients of 1 in 36, and 1 in 52.
Hence to maintain a minimum speed of 40 miles per hour with locomotive
power on a line with long gradients of 1 in 40 involved on those parts
of the line a wasted power of nearly 4 times that usefully employed; and
if a minimum limit of 60 miles per hour were contemplated, a locomotive
of the most powerful class in existence three years subsequent to Mr.
Brunel’s report advising the adoption of the Atmospheric System would
only have been able to take a single carriage up an incline of 1 in 52.
So heavily at high speeds on steep gradients is the performance of a
locomotive taxed by the resistance due to its own dead weight.[75]
* * * * *
A comparison has now to be made between the cost of power as developed
by a locomotive and as developed by a stationary engine.
From the well-known experiments made for the information of the Gauge
Commissioners in December 1845, taking the high speed trials as the
basis of calculation, it appears that 4·5 lbs. of coke per horse-power
per hour may be taken as the average consumption of the engine.[76]
It will be well, however, to allow for the improvement which was at the
time anticipated in locomotive working, and to assume an expenditure of
4 lbs. of coke per indicated horse-power per hour, as representing the
case then for the locomotive engine.
Coke may be taken to have at that time cost 21_s._ a ton, or ·0094_s._
per lb. Moreover, a careful analysis of the Great Western Railway
half-yearly reports, for 1844 and 1845, shows that for every shilling
expended in coke, 1·44 shillings were expended on the average in wages,
oil and waste, repairs, etc.
Putting the results together, it appears that for each single indicated
horse-power delivered by a high-speed locomotive, the cost per hour was
0·0915_s._ or 1·098_d._; that is to say, about 1-1/10_d._ per hour.
Let this now be compared with the cost per horse-power per hour at which
the best Cornish pumping engines had long been known to perform the
work. This comparison is manifestly a rational one--with reference to
the kindred employment of engine power in atmospheric pumping-engines.
The performances of nearly all the pumping-engines in Cornwall were for
many years so systematically and exactly reported, and the reports of
each were so critically scrutinised by the rival makers, that the data
they supply may be relied on without hesitation. It was well known that
the best of the engines continuously performed useful work with a
consumption of coal at the rate of 2·33 lbs. per delivered horse-power
per hour, or, counting coal at 16_s._ per ton (a fair price on the South
Devon), at the cost of ·2_d._, or one-fifth of a penny per horse-power
per hour.
But it was not in its consumption of fuel alone that stationary power
was the more economical; the expenditure in wages, oil, and tallow on
one of the pumping-engines above referred to, when doing 200 horse-power
of useful work, did not exceed 20_s._ for the twenty-four hours, or
one-twentieth of a penny per horse-power per hour, while the cost of
repairs was merely nominal.
Thus if fuel, wages, oil, and tallow be brought into one item, it is
seen that the cost of one horse-power in stationary engines such as the
then existing Cornish engines was only ·25_d._ per hour, or less than
one-fourth of its cost when developed by a locomotive, which has been
shown to have been 1·098_d._ per hour.
[Illustration: PLATE III
THE ROYAL ALBERT BRIDGE.
H. Adlard. Sc.]
CHAPTER VII.
_RAILWAY BRIDGES AND VIADUCTS._
1. BRICKWORK AND MASONRY BRIDGES--HANWELL VIADUCT--MAIDENHEAD
BRIDGE--FLYING BRIDGES--LETTER FROM MR. BRUNEL ON BRIDGE
CONSTRUCTION (DECEMBER 30, 1854)--2. TIMBER BRIDGES--SONNING
BRIDGE--BATH BRIDGE--STONEHOUSE VIADUCT--BOURNE VIADUCT--ST. MARY’S
VIADUCT--VIADUCTS ON THE SOUTH DEVON RAILWAY--IVY-BRIDGE--VIADUCTS
ON THE SOUTH WALES RAILWAY--NEWPORT--LANDORE--VIADUCTS ON THE
CORNWALL RAILWAY--ST. PINNOCK--VIADUCTS ON THE WEST CORNWALL AND
TAVISTOCK RAILWAYS--PRESERVATION OF TIMBER--3. CAST-IRON
BRIDGES--LETTER ON USE OF CAST IRON (APRIL 18, 1849)--HANWELL
BRIDGE--EXPERIMENTS ON CAST-IRON GIRDERS--EXTRACT FROM LETTER TO
SECRETARY OF COMMISSION ON APPLICATION OF IRON TO RAILWAY
STRUCTURES (MARCH 13, 1848)--4. WROUGHT-IRON BRIDGES--GIRDER
BRIDGES--EXPERIMENTS ON WROUGHT-IRON GIRDER--OPENING
BRIDGES--TRUSSED BRIDGES--NEWPORT VIADUCT--WINDSOR BRIDGE--CHEPSTOW
BRIDGE--METHOD OF SINKING THE CYLINDERS--DESCRIPTION OF THE MAIN
TRUSS--THE FLOATING OPERATIONS--THE ROYAL ALBERT BRIDGE AT
SALTASH--THE CENTRE PIER--DESCRIPTION OF THE SUPERSTRUCTURE--THE
FLOATING AND RAISING OF THE TRUSSES--OPENING OF THE BRIDGE BY H. R.
H. THE PRINCE CONSORT--_NOTE_: EXPERIMENTS ON MATTERS CONNECTED
WITH BRIDGE CONSTRUCTION.
In Chapter IV. a general history has been given of the railways of which
Mr. Brunel was the engineer; but the bridges and viaducts designed by
him are so numerous and important that it has been thought advisable to
devote a separate chapter to their consideration.
The bridges selected for mention have been grouped according to the
nature of the material used in their superstructure. This arrangement is
the most convenient one for giving a concise description of the most
remarkable of Mr. Brunel’s bridges, and for stating the circumstances
which guided him in the determination of the particular form of
construction used in each case.
The works are therefore divided into four groups, namely, brickwork and
masonry, timber, cast iron, and wrought iron.[77]
_Brickwork and Masonry Bridges._[78]
The viaduct which carries the Great Western Railway over the valley of
the river Brent near Hanwell is the first of Mr. Brunel’s important
railway works.[79] It is a handsome brickwork structure, 65 feet high,
with eight semi-elliptical arches, each 70 feet span and 17 feet 6
inches rise. The spandrils of the arches are lightened by longitudinal
spandril-walls; the piers are also hollow, and the structure is
throughout made as light as possible. It is on this account interesting,
as showing the care taken by Mr. Brunel from the commencement of his
practice to distribute the material in the simplest and most effective
manner.[80]
The great bridge over the Thames at Maidenhead contains two of the
flattest, and probably the largest arches that have yet been constructed
in brickwork. The river, which is about 290 feet wide, flows between low
banks; in the middle of the stream there is a small shoal, of which Mr.
Brunel took advantage in building the centre pier.
It was originally intended that the foundation of the bridge should be
on the chalk, which was at a short distance below the surface; but it
was found to be very soft, and Mr. Brunel therefore decided to place the
foundations of the bridge on a hard gravel conglomerate overlying the
chalk. The main arches are semi-elliptical, each of 128 feet span and 24
feet 3 inches rise. They are flanked at each end by four semicircular
arches, one of 21 feet span, and three of 28 feet span, intended to give
additional water-way during floods. The radius of curvature at the crown
of the large arches is 165 feet, and the horizontal thrust on the
brickwork at that point is about 10 tons per square foot.
In the interior of the structure immediately landward of the large
arches, Mr. Brunel constructed flat arches loaded with concrete. The
centerings of these were struck, and an active thrust opposed to the
main arches before their centerings were eased.[81] The line of
pressure of each main arch was diverted downwards by the thrust of the
flat arch adjoining it without the necessity of employing a great mass
of brickwork in the abutment.
The woodcut (fig. 1) shows the form of the main arches and the flat arch
referred to.[82]
[Illustration: Fig. 1. Maidenhead Bridge.
_Longitudinal Section._
_Scale of feet._]
The Maidenhead bridge is remarkable not only for the boldness and
ingenuity of its design, but also for the gracefulness of its
appearance. If Mr. Brunel had erected this bridge at a later period, he
would probably have employed timber or iron; but it cannot be a matter
of regret that this part of the Thames, although subjected to the
dreaded invasion of a railway, has been crossed by a structure which
enhances the beauty of the scenery.
* * * * *
There are two other large brick bridges over the Thames, one at
Gathampton and another at Moulsford, that at Moulsford crossing the
river obliquely at an angle of 45°. In each of these bridges there are
four arches, of 62 feet span on the square.
Other good examples of brick bridges are the turnpike road bridge, 60
feet high, with three arches, across the deep cutting at Sonning Hill,
and the bridge, with one opening of 60 feet and four side arches of 18
feet span, over the river Kennet at Reading.
The bridge over the Avon at Bathford, of 87 feet span, and the bridge
crossing the same river at Bath, with an arch of 88 feet span, are
handsome Bath-stone structures with semi-elliptical arches. Near Bristol
there is an ornamental bridge of masonry with three Gothic arches, the
centre arch having a span of 100 feet.[83] Another bridge of Gothic
design, with two arches of 56 feet span, carries the railway over the
Floating Harbour.[84]
* * * * *
The bridges which have hitherto been noticed are all on the Great
Western Railway. On the Bristol and Exeter Railway there is a large
stone bridge over the New Cut at Bristol, built in 1840, which has a
single segmental arch of 120 feet span, and 20 feet rise. Owing to some
imperfect workmanship in the interior masonry of the arch, and possibly
to some unequal yielding of the abutments, the crown sunk much more than
had been expected.
On his later railways Mr. Brunel did not build large arches of brickwork
or masonry, though he constructed several lofty and extensive viaducts
of these materials with spans varying from 40 to 60 feet.
Mr. Brunel seldom employed artificially piled foundations to support
masonry. When the ground was soft, he preferred to rely on a large
extent of bearing surface, and ensured uniformity of settlement by an
accurate distribution of the load. Several of his large viaducts and
bridges, standing on ground of a soft and spongy nature, were
constructed on this principle.
A class of bridge of striking outline was used in the cuttings on the
Bristol and Exeter Railway, and on the other railways subsequently made.
Bridges of this class were called flying bridges. Instead of arches
resting on piers and abutments, the bridge has a single arch, reaching
from one side of the cutting to the other, and springing from the
slopes, which it helps in some measure to support. A flying bridge of
large dimensions near Weston-super-Mare carries a road across the
cutting at a height of 60 feet above the line of rails, with a clear
span of 110 feet.
The quantity of masonry in these bridges is much less than in those of
the ordinary construction; and lofty and expensive centering is not
required, as the bridge can be built before the cutting is excavated to
its full dimensions.
This class of bridge, by the avoidance of abutments and counterforts,
simplifies the construction of skew arches, while on sharp curves it
presents but little obstruction to the view along the line.
A curious use of arches of this construction, as applied by Mr. Brunel,
may be seen on the South Wales Railway near Llansamlet, between Neath
and Swansea. A deep cutting through the coal measures showed a tendency
to slip, and a large amount of excavation would have been required to
flatten the slope, as a hill rose immediately above the side of the
cutting. Four of these flying arches were thrown across the cutting at
short intervals, and weighted with heavy copper slag, so that the sides
of the cutting are kept apart by the thrust of the loaded arches.
Among the skew bridges on Mr. Brunel’s railways, there are a few of
extreme obliquity. Of these may be mentioned two large road bridges near
Berkeley, over the Bristol and Gloucester Railway, one being 48° and the
other 53° off the square. Both the bridges are of brickwork, and in the
arch of the first one, which was set in Roman cement, hoop iron was
introduced in the manner successfully employed by Sir Isambard Brunel.
On the South Devon Railway, near Plympton, there is a skew bridge 63°
off the square.
On the Great Western Railway, in the neighbourhood of Bath and Bristol,
there are skew bridges of ashlar masonry built on the mechanically
correct principle of spiral tapering courses, the bed-joints in every
part of the arch being made at right angles to the lines of pressure. By
this method the arch does not depend for its stability on the friction
and cohesion of the materials, as it does to a great extent in very skew
bridges, built in the usual way with spiral parallel courses, especially
when the arches are semi-circular or semi-elliptical.
* * * * *
Mr. Brunel’s bridges of masonry and brickwork were well known for the
comparatively small quantity of material used in them; and, though it
was requisite that the materials and workmanship should be of superior
quality, their cost was comparatively small.
The specifications he prepared for all his works, and on which the
contracts were based, were noted for the completeness with which they
were drawn up, and for their not requiring a standard of perfection
higher than that which was actually to be carried out. The confidence
with which Mr. Brunel was regarded enabled him to insist with effect on
the work being executed according to his interpretation of the
contract.
In connection with the design of engineering works, and especially of
brickwork and masonry bridges, the following letter from Mr. Brunel to
one of his assistants, who was abroad, will be found interesting:--
December 30, 1854.
Let me give you one general piece of advice--that while in all
works you endeavour to employ the materials used in the most
economical manner, and to avoid waste, yet always put rather an
excess of material in quantity. You cannot take too much pains in
making everything in equilibrio; that is to say, that all forces
should pass _exactly_ through the points of greater resistance, or
through the centres of any surfaces of resistance. Thus, in
anything resembling a column or strut, whether of iron, wood, or
masonry, take care that the surface of the base should be
proportioned that the strain should pass through the centre of it.
Consider all structures, and all bodies, and all materials of
foundations to be made of very elastic india-rubber, and proportion
them so that they will stand and keep their shape: you will by
those means diminish greatly the required thickness: _then add 50
per cent_. So in trussed framework of wood or iron, experience
shows that you cannot refine too much upon the perfection of the
designing of every little detail by which all strains are carried
exactly through the centres of the rods or struts and the centres
of the bearing surfaces. And remember, always in retaining walls to
give plenty of batter; never build an upright wing-wall, or
retaining wall. To a man who has an instinctively mechanical
mind--and no other can be an engineer--the advice I have given you
above is all I need say; but this advice is the result of a good
deal of experience, purchased by failures of my own, and by looking
at those of others, and is, I assure you, valuable advice, to be
followed literally and strictly, and not to be considered as a mere
theoretical refinement, to be neglected in practice. Practically
too much attention cannot be paid to these precautions. I have
found that there is not a single substance we have to deal with,
from cast-iron to clay, which should not practically be treated
strictly as a yielding elastic substance, and that the amount of
the compression or tension, as the case may be, is by no means to
be neglected in practice any more than in theory. Bear in mind also
that which is too often neglected and involves serious
consequences, that masonry or brickwork has not half the strength
which is generally calculated upon until the mortar is hard, and
that you cannot keep centres or shores up too long.
_Timber Bridges and Viaducts._
Mr. Brunel’s timber bridges and viaducts are remarkable on account of
the extensive scale on which he employed that material, and the simple
and efficient type of construction which he adopted in the largest
structure as well as in the smallest.
In 1841 Mr. Brunel constructed a timber bridge of five spans to carry a
public road over the Sonning cutting of the Great Western Railway, a
short distance east of Reading. The total width of the space across
which the road had to be carried was 240 feet. The superstructure rests
on four tall frameworks or trestles of timber forming the piers. Two of
these piers are on either side of the railway, and the others are about
halfway up each slope.
The road rests on a platform of timber planking, carried on three
longitudinal beams, which are supported at nearly equal distances by
timber struts radiating from points on the piers about 12 feet below the
level of the carriage road. The system of arrangement of these struts
will be best understood by a reference to the woodcut given below (fig.
5, p. 187) of one of the Cornwall viaducts, of which the Sonning bridge
may be regarded as in some measure the prototype.[85]
* * * * *
The skew timber bridge on the Great Western Railway near the Bath
Station, carrying the line over the river Avon, was constructed about
the same time as the Sonning bridge. It has two spans of 36 feet each on
the square, but the obliquity is so great that the span on the skew is
89 feet. Each opening has six laminated arched ribs parallel to the line
of the railway. These support the platform of the bridge, and are built
up in five layers of curved Memel timber, six inches thick, bolted
together. The thrust is counteracted by iron ties connecting the ends of
the ribs. The inner spandrils are filled in by cross-ties and braces,
and those of the outer ribs by ornamental cast ironwork.
* * * * *
The two bridges already described are almost the only timber bridges of
importance on the main line of the Great Western Railway from London to
Bristol. Shortly after the completion of this railway Mr. Brunel began
to make an extensive use of timber in his designs, and in so doing took
full advantage of the largeness of the material, in order to avoid
intricacy of construction.
A well-known arrangement for forming beams of greater strength than
could be obtained by single pieces of timber was adopted by Mr. Brunel
after a careful investigation of its merits. This arrangement consists
in joining together two beams of timber placed one above the other, by
means of bolts and joggles, so as to form a beam nearly equivalent in
strength to a single piece of timber of the same depth as the two pieces
united.[86] By this plan, the length which could be spanned by simple
beams, without the introduction of trussed framework, was nearly
doubled.
The distance between the piers of railway bridges is generally too great
to allow of the superstructure being constructed of simple beams, and in
such cases Mr. Brunel adopted forms of framing similar in the
arrangement of their parts to the common designs of king and queen
trusses employed in roofs.
* * * * *
One of Mr. Brunel’s early timber viaducts was that erected in 1842 at
Stonehouse, on the Bristol and Gloucester Railway. It consisted of a
series of five openings of queen trusses 50 feet span, resting on piers
formed of timber trestles.
[Illustration: QUEEN TRUSS.]
[Illustration: KING TRUSS.]
In the Bourne viaduct, across the Stroudwater Canal, on the Cheltenham
and Great Western Union Railway, there was a span of 66 feet, with three
timber trusses, for the two lines of way. Each of these trusses may be
described as a king truss with an internal queen truss. The inclined
timbers or principals rested in iron shoes upon the piers, and were
connected together by bolts and joggles.
The upper horizontal or collar beam of the queen truss carried the
roadway planking, which was continued upon beams supported by the
principals. The timbers carrying the roadway received support from
struts radiating from the feet of the queen posts, which were connected
with the apex of the king truss by iron ties. The horizontal tie bars
were of wrought iron. The arrangement of the truss is shown in the
woodcut (fig. 2).
[Illustration: Fig. 2. Bourne Viaduct.
_Scale of feet._]
The side openings consisted of four spans of 30 feet, with trusses of
the Stonehouse viaduct type, of one span of 25 feet and ten spans of 20
feet, with double beams.
The St. Mary’s viaduct, across the canal in the Stroud Valley, was
constructed with one span of 74 feet, with trusses similar to those at
the Bourne viaduct.[87]
In the year 1846 Mr. Brunel made an elaborate series of experiments on
the strength of large timber. Some account of these is given in the note
to this chapter.
Fortified by the information thus obtained, he was able to proceed with
confidence to an extensive use of timber in the viaducts of the South
Devon, the Cornwall, and other railways.
Between Totness and Plympton, the South Devon Railway, running along the
skirts of Dartmoor, crosses four deep valleys, by lofty viaducts, all of
the same design.
Three of them can be seen at one time, and they form striking and
elegant features in the landscape.
The viaduct at Ivybridge is the highest of these. It is on a curve, and
has eleven openings of 61 feet each; the extreme height is 104 feet.
[Illustration: Fig. 3. Ivybridge Viaduct.
_Scale of feet._]
The piers are of masonry, each consisting of two slender and slightly
tapered shafts about 7 feet square, rising to the level of the rails.
The superstructure was originally designed for a railway on the
Atmospheric System, and was therefore only intended to bear the load of
a train of carriages. The framework was placed below the level of the
rails, and, as will be seen in the woodcut (fig. 3), it consists of a
polygonal frame, with a few subsidiary struts, the feet of the main
timbers being tied together by wrought-iron rods. There are two of these
frames, one at each side of the bridge, to support the planking of the
roadway. Before the construction of the viaducts was proceeded with, a
complete span of the superstructure, consisting of a pair of the frames
with the planking, was erected at Bristol, and tested to ascertain the
efficiency of every part.
When it became necessary to strengthen the superstructure to enable it
to carry the weight of locomotives, a strongly trussed parapet was added
above the trusses, as shown in the woodcut. After the lapse of twenty
years, the timber having begun to decay, wrought-iron girders have been
inserted, which rest on the stone piers; the framing, however, has not
been removed.
* * * * *
Shortly after the completion of the viaducts on the South Devon Railway,
those on the South Wales Railway were constructed. The most important on
this line are those at Landore and Newport.
The viaduct at Landore, near Swansea, is 1,760 feet long, as the railway
here crosses a wide valley. It has 37 openings, and there are a variety
of spans, one of 100 feet, two of 73 feet, two of 64 feet, two of 50
feet, and the rest of about 40 feet each. Most of these consist of a
superstructure of queen trusses. The piers are of different materials,
some being almost entirely of masonry, some partly of masonry and partly
of timber, and others entirely of timber, according to the nature of the
foundation.[88] The chief feature is the centre span, with an opening
of 100 feet, the superstructure of which is a very fine piece of
timber-work.[89] It has four trusses, one on either side of the two
lines of rails, of the form shown in the woodcut (fig. 4). The truss
consists of a four-sided frame placed within a five-sided frame, the
angles of each polygon being connected by bolts and struts with the
middle of the sides of the other polygon.
[Illustration: Fig. 4. Landore Viaduct.
_Scale of feet._]
The planking of the roadway rests on double beams, supported at several
points in the manner shown in the woodcut, each point having
suspension-rods to connect it with the nearest angles of the frames. The
arrangement of the double polygonal frame and of the tie-rods enables
the transverse strength of the timbers to exercise considerable
resistance to any distortion of the shape of the truss by a rolling
load. To prevent any tendency of the top of the frame to yield sideways
under the compressive strain, the tops of the trusses are connected by
transverse struts or braces, the two outside trusses being steadied by
raking ties attached to outriggers projecting from below the flooring of
the bridge. The thrust of the polygonal frames is resisted by
wrought-iron tie-bars at the level of the roadway beams. All the
tie-rods in this bridge are double, with one bar on each side of the
timbers, to avoid the necessity of making large bolt-holes.[90]
The viaduct at Newport consists of eleven spans with queen trusses,
resting on piles. The main span, over the river Usk, is 100 feet, and
was constructed with timber trusses very similar to those at Landore.
Shortly before it was finished, the viaduct was burnt down. In
rebuilding it, wrought-iron trusses were employed for the main span.
* * * * *
The works of the Cornwall Railway were commenced in the year 1852. The
district through which the line passes is very deficient in the
materials requisite for the construction of a railway. The granite of
the country is for the most part only applicable for ashlar; and the
slate, which is flat-bedded and so far fit for rubble masonry, is
frequently inferior in quality.
In consequence of the number of valleys that the railway had to cross,
the aggregate length of the viaducts, thirty-four in number, exclusive
of the Saltash bridge, is upwards of four miles on a line of sixty
miles. By the use of timber, a great saving was effected in the first
cost of the works; and though it is a material which in time requires
renewal, its use on the Cornwall Railway enabled the line to be made
with the capital at the command of the Company; while, allowing for the
cost of subsequent repairs, the total expenditure did not differ much
from what it would have been had the superstructure of the viaducts been
of more durable materials. The comparatively small cost of these
structures enables them to be, in certain places, economically
substituted for embankments, as was done on the Cornwall Railway.
The viaducts are to be found over the whole length of the line, but they
are most frequent between the Liskeard and Bodmin Road stations, where
the railway crosses numerous branches of the Glynn valley.
Most of these viaducts are of one type of construction.
The piers are formed of plain walls, built up to thirty-five feet below
the level of the rails, those of the more lofty viaducts being
strengthened by buttresses. In the woodcut (fig. 5) is shown a portion
of the St. Pinnock viaduct, from which the form of these piers will be
understood.
This viaduct is the loftiest on the Cornwall Railway, the rails being at
a height of 153 feet above the ground. A description of the
superstructure will serve to explain the design of the principal
viaducts on the line.
The roadway planking rests on three beams, which run longitudinally
throughout the whole length of the viaduct. Each of these beams consists
of two pieces of timber, one above the other, fastened together by bolts
and joggles. The piers are 66 feet apart, centre to centre, and the
longitudinal beams are supported, at four nearly equidistant points in
this space, by straight single timbers radiating from the tops of the
piers. The feet of the timbers, which rest on the masonry in cast-iron
shoes, are connected together by wrought-iron tie-bars; and the
framework is made rigid by iron diagonals.
[Illustration: _Scale of Feet_ _Transverse section_
_Plan of base of pier._ _Plan of top of pier._
Fig. 5. St. Pinnock Viaduct.]
It will be observed in the transverse section (fig. 5) that the whole
weight of the superstructure is concentrated immediately over those
points in the piers where the three buttresses meet. The diagonal braces
which are attached to each set of the main timbers give transverse
stability to the superstructure.[91]
It was desirable, both in first construction and in subsequent repairs,
to have a uniform dimension for the spans, and the subdivision of 66
feet was determined on as being suitable for the economic construction
of the greater part of the work. The subdivision of this length was such
as to allow of single whole timbers being sufficient for the direct
supports of the longitudinal beams; and as these beams were supported at
intervals of 15 to 20 feet, no intermediate trussing was required. As
the inclined timbers met the tops of the piers at a moderate
inclination, the outward thrust caused by unequal loading of the spans
of the viaduct was inconsiderable, and was easily counteracted by light
iron ties.
The stone for the piers was for the most part procured in the
neighbourhood, the design of the masonry being such as to enable stone
of the country to be used; and, as the timber superstructure was built
in pieces of moderate size,[92] and easily obtained, the expenditure was
probably not far from the minimum under the existing conditions.[93]
On the South Devon and Tavistock Railway, the viaducts are six in
number, and from 62 to 132 feet in height. In these the piers were made
of a somewhat simpler form than those just described. At the lofty
viaducts, the buttresses were made with a uniform batter throughout
their height. The Walkham viaduct, near Tavistock, 132 feet high, with
fifteen openings of 66 feet span each, may be considered to exhibit the
most matured design of Mr. Brunel’s timber viaducts.
On the West Cornwall Railway a type of viaduct similar to that described
above was adopted; but as the general height was not so great, the spans
were 50 feet each, and the longitudinal beams were supported at three
points in each span, instead of at four as on the Cornwall Railway. In
consequence of the nature of the foundations, the piers of the nine
viaducts on this line were for the most part formed of upright timbers
well braced together, standing upon masonry footings. The viaduct at
Angarrack, 98 feet high, with 16 spans, which was constructed in 1851,
was remarkable for its light appearance, owing to the small number of
timbers in the superstructure and piers.
Mr. Brunel paid great attention to the preservation of the material of
the timber bridges and viaducts. As early as 1835 he had been in
communication with Mr. Faraday as to the best method of testing the
extent to which the Kyanising solution penetrated into wood. Mr. Brunel
made a careful trial of all the different methods of preserving timber,
and employed the more successful of them on a very considerable scale.
He was so impressed with the importance of the preserving processes
being properly applied, that he on several occasions preferred to keep
the operation of preserving the timber in the hands of the Company, in
order that it might be done thoroughly, and under his own supervision.
He also minutely attended to the details by which timber structures may
be protected from decaying influences.
_Cast-Iron Bridges_.
Mr. Brunel did not make an extensive use of cast iron for the
superstructure of bridges. His views as to the employment of this
material in girders are clearly expressed in the following extract from
a letter to one of the Directors of the Great Western Railway:--
April 18, 1849.
Cast-iron girder bridges are always giving trouble--from such cases
as the Chester Bridge, and our Great Western road bridge at
Hanwell, which, since 1838, has always been under repair, and has
cost its first cost three times over, down to petty little ones,
which, either in frosty weather or from other causes, are
frequently failing. I never use cast iron if I can help it; but, in
some cases it is necessary, and to meet these I have had girders
cast of a particular mixture of iron carefully attended to, and I
have taught them at the Bridgewater foundry to cast them with the
flange downwards instead of sideways. By these means, and having
somebody always there, I ensure better castings, and have much
lighter girders than I should otherwise be obliged to have. The
number I have is but few, because, as I before said, I dislike
them, and I pay a price somewhat above ordinary castings, believing
it to be economy to do so.
I won’t trust a bridge of castings run in the ordinary way, and at
foundries where I have not a person always watching; and, even if I
did, the weight requisite in a beam of ordinary metal and mode of
running would more than make up for the reduced price.
The bridge at Hanwell referred to in this letter was one on the main
line of the Great Western Railway, over the Uxbridge road. In 1847 the
planking caught fire, and the cast-iron girders were destroyed by the
heat.
The researches of Mr. Eaton Hodgkinson had drawn attention to the
importance of a proper proportionment of the top and bottom flanges of
cast-iron girders, and Mr. Brunel now made some experiments on this
point. As part of this investigation, eight girders, 30 feet long and 16
inches deep, were tested by weights until they gave way. The
comparative areas of the top and bottom flanges were varied until a
correct proportion between the two was arrived at. The general result of
these large-scale experiments showed a lower breaking-weight than that
deduced from Mr. Hodgkinson’s formula.
When Mr. Brunel afterwards had occasion to use cast-iron girders, which
was chiefly for road bridges over railways, they were made of the form
which his experiments had shown to be the best;[94] but he repaired the
Hanwell Bridge with wrought iron.
At about the same time the necessity for spanning wide openings had led
to larger girders being required than could be manufactured in single
castings, and Mr. Brunel had a large cast-iron girder made, 46 feet long
and 4 feet deep, of five pieces bolted and keyed together. It was tested
until it gave way with a load of 92 tons on the middle. The result
showed that the several parts had been well connected, and that the
strength of the beam was not much less than the calculated strength of a
beam of the same size in a single piece. Mr. Brunel did not, however,
use girders of this construction, as the rapid introduction of wrought
iron rendered it unnecessary.
Cast iron was introduced, though not for girders, in many of the brick
and stone bridges on the Great Western Railway. It was used in the form
of troughs sunk into the crown of the arch in bridges where the headway
was very limited. The rails were laid along the bottom of the trough
within a few inches of the soffit or underside of the arch.
Although, after the careful experiments and investigations he had made,
and the experience he had obtained, Mr. Brunel did not make use of cast
iron for large girders, he looked forward to the possibility of such
improvements being introduced into the manufacture as would enable sound
castings of considerable size to be made of homogeneous material.
He expressed this opinion in a letter to the Secretary of the Commission
on the Application of Iron to Railway Structures. This Commission (which
Mr. Brunel called ‘The Commission for stopping further improvements in
bridge building’) was appointed ‘for the purpose of inquiring into the
conditions to be observed by engineers in the application of iron in
structures exposed to violent concussions and vibration.’ Mr. Brunel, in
common with most engineers, thought it would be very inexpedient that
any _règles de l’art_ should be laid down, and took up the cudgels
boldly on behalf of the liberty of the profession:--
March 13, 1848.
At present cast iron is looked upon, to a certain extent, as a
friable, treacherous, and uncertain material; castings of a limited
size only can be safely depended upon; wrought iron is considered
comparatively trustworthy, and by riveting, or welding, there is no
limit to the size of the parts to be used. Yet, who will venture to
say, if the direction of improvement is left free, that means may
not be found of ensuring sound castings of almost any form, and of
twenty or thirty tons weight, and of a perfectly homogeneous
mixture of the best metal? Who will say that beams of great size of
such a material, either in single pieces or built, may not prove
stronger, safer, less exposed to change of texture or to injury
from vibration, than wrought-iron, which in large masses cannot be
so homogeneous as a fused mass may be made and which when welded is
liable to sudden fracture at the welds?[95]
_Wrought-Iron Bridges._
Notwithstanding the cost of wrought iron, but a short time elapsed
between its introduction into bridge building and its use in structures
of great magnitude. Mr. Brunel had been long familiar with the
application of riveted wrought-iron work, and he was the first to
encourage its use on a large scale in shipbuilding by recommending its
adoption in the ‘Great Britain’ steam-ship in 1838.
_Girder Bridges._
The strains on girders made of homogeneous material have been carefully
and ably calculated by mathematicians; and the investigations thus made
have directed inquiry into the right channels for determining the nature
of the stresses on the several parts of the built-up structures now so
much in use. Principles have by degrees been laid down, and lines of
thought have been suggested and followed out which were unknown at the
time when wrought-iron girders were first introduced in the construction
of railway bridges.[96]
* * * * *
[Illustration: _Scale of feet_.
Fig. 6. Experimental Girder.
_Transverse Section_.]
Shortly after Mr. Brunel began to use wrought iron for bridge girders,
he made an experiment in order to determine the weak points of a large
wrought-iron plate-girder. Mr. Edwin Clark, in his work on the
‘Britannia and Conway Tubular Bridges,’ vol. i. p. 437, gives a
description of what he justly terms ‘this magnificent experiment.’ The
girder was of the section shown in the woodcut (fig. 6), 70 feet in
length, and of ¼-inch plate throughout. It was weighted gradually, and
gave way with a load of 165 tons on the centre, by the tearing apart of
the vertical web plate near the ends of the girder. When this portion
had been strengthened, and the girder again loaded, it gave way with a
load of 188 tons by the simultaneous failure of the top and bottom
flanges, that is to say, of the plates forming the triangles shown in
the woodcut.[97]
The superior tensile strength of wrought iron to that of cast iron, and
the facility with which pieces could be joined together by riveting,
enabled girders of great size to be made. The thin wrought-iron plates
were arranged so as to form the top and bottom flanges of the girders as
well as the upright web connecting them. The metal in the top of a
girder being in compression, it was important so to dispose it that it
should resist the tendency to yield sideways under the strain. This
requirement was met in the experimental girder by the triangular section
of the top flange; and the convenience of this form for joining together
a number of plates, without difficulty or the use of long rivets, led
Mr. Brunel to use the triangular section also for the bottom flange.
[Illustration: _Scale of feet._
Fig 7. Girder on South Wales Railway, 70 feet span.
_Transverse Section._]
Subsequent improvements in the facilities for bending wrought-iron
plates enabled him to use a form of cross section of wrought-iron
girder, the top flange of which was a nearly circular tube, the best
shape of strut to resist longitudinal compression. It is shown in the
woodcut (fig. 7), and was used in many of his bridges.
This form was afterwards modified to that shown in fig. 8. The
semicircular top plate is stiffened by occasional cross diaphragms, and
while it was a good form to resist compression, it was more easily
painted than the closed-in top flanges shown in figs. 6 and 7.
The forms of wrought-iron girder already referred to are those known as
plate girders, with continuous webs made of plates riveted together, and
therefore analogous to the beams of cast iron which they almost entirely
superseded. On Mr. Brunel’s railways there are a great number of bridges
of these forms of girder, where the spans do not exceed 100 feet. For
larger spans he used wrought iron, in large and deep trussed frames, by
which means a great degree of economy was attained in the employment of
the material.
[Illustration: _Scale of feet._
Fig. 8. Girder on Eastern Bengal Railway, 92 feet span.
_Transverse Section._]
The care which he had taken to satisfy himself of the action of the
strains in plate girders was of service in all the greater structures he
designed, as in all of them he employed wrought-iron girders to carry
the roadway, of a type somewhat similar to those already described, the
girders being supported at frequent intervals by the main framework or
truss.
_Opening Bridges._
The first large opening bridge which Mr. Brunel constructed was a
roadway swing bridge, 12 feet wide, across the new lock at the Bristol
Docks. The length of the overhanging end is 88 feet, and the other, or
tail end, which is 34 feet long, rests upon two wheels, which travel on
a circular rail. The weight of the overhanging end is rather more than
counterbalanced by large blocks of cast iron, forming part of the
pavement of the tail end. Almost the whole weight is borne on a centre
pivot, assisted by four wheels in fixed bearings, upon which runs an
inverted circular rail attached to the underside of the bridge. On the
pivot, which rests on a large cast-iron bed-plate, are two discs, one of
steel and the other of brass, which can readily be lubricated, or taken
out and renewed.
[Illustration: _Scale of feet._
Fig. 9. Cumberland Basin Swing Bridge.]
On the sides of the bridge are longitudinal wrought-iron plate-girders.
The top flange is pear-shaped, and the bottom flange triangular, having
three curved plates. The flanges are connected together by a vertical
plate web of wrought iron. The section is shown on the woodcut (fig. 9).
It admits of very simple riveting, without the use of angle irons. The
form of the bottom flange is suited to the compressive strain it has to
bear when the bridge is being moved. The top flange has also
wrought-iron tie-bars within the tube. When the bridge is across the
lock and open for traffic, the overhanging end rests on cams, which are
tightened up so as to lift and support the ends of the girders. As the
bridge rests almost entirely on a pivot of small diameter, it turns with
great ease.
Near Gloucester there are two skew swing bridges somewhat similar to
each other in arrangement. Almost all the weight while turning is
supported on the piston of a hydraulic press, and the bridge therefore
turns round on the water in the cylinder. The first bridge is on the
main line of railway leading to South Wales, across a branch of the
River Severn, and is for two lines of way. It has three girders, 125
feet long, of the form shown in fig. 7 (p. 194). The water pivot is in
the middle of the length of the bridge, which spans two openings of 50
feet on the square. Before being turned the bridge was intended to be
lifted slightly off its bearings by the hydraulic press, and steadied by
four wheels, on which a portion of the weight was to be made to rest by
long springs within the girders, the range of which was to be limited in
one direction by a fixed stop. The central pier consists of five
cylinders of cast iron, each 6 feet in diameter, filled with concrete,
surmounted by a cast-iron ring or roller path. The railway company was
obliged to make this an opening bridge in order to provide for the free
navigation of the river should the old stone bridge lower down be
altered. This has not been done, and the railway swing bridge,
constructed in 1851, has not yet been opened.
The other swing bridge at Gloucester is on the Dock branch, for one line
of way, with an opening of 50 feet on the square, the overhanging length
of the girders being 70 feet. While raised from its bearing and turning
on its water pivot it is steadied by two tail wheels, like the bridge at
the Bristol Docks.
On the Bullo Pill branch of the South Wales Railway there is a small
wrought-iron drawbridge, for one line of way, of 30 feet span. It is a
lifting bridge on the _bascule_ principle, like many bridges over canals
in this country and in Holland. The opening part turns on a horizontal
axle, and is lifted by rods attached to the ends of two large beams or
levers, turning vertically, which are supported above the railway on a
timber framework. At the other ends of these beams is a counterbalance
weight. The bridge is opened or shut by pulling down either end of the
beams with a small chain.
The other bridges are on the main line of the South Wales Railway, and
are four in number, each for two lines of way.
One at Loughor is a wrought-iron swing bridge, of 30 feet opening, of
the ordinary construction, with girders 90 feet in length, resting upon
36 rollers, which are secured in a ring concentric with the pivot. The
opening and closing is effected by means of a crab, fixed clear of the
bridge, near the centre. A chain passes from the overhanging end of the
bridge to this crab, and taking one or two turns round the barrel, to
ensure a sufficient amount of friction, is led to the tail end. The
bridge can thus be opened or shut by turning the crab handle in opposite
directions. The overhanging end, when across the river, is raised
upwards to a small extent by weighted levers, and wedges are then drawn
in under it to give it a solid bearing.
At Kidwelly and at Haverfordwest there are wrought-iron lifting bridges,
the former of 20 feet, and the latter of 30 feet span. Each of these
turns on a horizontal axle like the Bullo Pill bridge; but, instead of
being lifted by levers overhead, it has a narrow, heavily-weighted tail
end, beneath the planking of the viaduct, which is pulled down with a
chain worked by a crab. The portion which carries each line of way is
made to open independently. In this form of bridge no wedges or
adjusting arrangements are required for the bearings of the overhanging
end.
Over the river at Caermarthen is a skew bridge of three girders, each
116 feet long, for a double line of way. It occupies two spans and rolls
back, so as to leave a 50-feet opening for the navigation. The swing
bridge at Bristol, already described, was at first intended to be a
rolling bridge, and to be furnished with wheels to run back on fixed
rails, but the difficulty of forming a good foundation for the wheel
path led to the design being altered. At Caermarthen the same difficulty
was overcome by putting wheels turning in fixed bearings on the pier and
abutment of the bridge. The undersides of the girders carry inverted
rails, and run back on the wheels. The bridge, when shut, is on an
incline of 1 in 50. When about to be opened it is made to assume a
horizontal position by turning a supporting cam to lower the overhanging
end, and the tail end then rises sufficiently to pass clear above the
part of the railway over which it runs back.
By this arrangement the bridge, while in motion, moves along a level
path. It is opened and closed by hydraulic machinery.
All these opening bridges have worked satisfactorily since they were
constructed.
_Trussed Bridges._
When the timber viaduct over the river Usk, at Newport, was burnt
down,[98] Mr. Brunel decided to form the new superstructure of the
centre opening with three iron trusses, for the two lines of way.
These are bow and string girders, of 100 feet span, and were made of
considerable height, not only to reduce the strain on each of the
members of the framework, but also in order that the rib or upper
portion of each truss might be braced diagonally to the corresponding
portion of the other trusses, and headway left for the locomotive
chimneys to pass underneath. This bracing counteracts any tendency of
the ribs to bend sideways under the compressive strain. The form of the
trusses is shown in fig. 1, Pl. IV. (p. 206). Each truss is a
wrought-iron polygonal arch of triangular section, from which is
suspended a horizontal girder supporting the roadway. This girder also
forms the tie which connects the feet of the arch and counteracts its
thrust. The diagonal braces shown on the elevation of the bridge prevent
the arch from being distorted by the unequal loading caused by a
passing train. The middle truss is twice the strength of each of those
at the outside, being made so by increasing the thickness of the plates.
One of the outside trusses was tested with a distributed load of 1½ tons
per foot-run of its length.
[Illustration: _Scale of feet._
Fig. 10. Truss of Windsor Bridge.
_Transverse Section._]
At about the same time that the Newport viaduct was reconstructed, Mr.
Brunel designed the bridge over the Thames on the Windsor branch of the
Great Western Railway. This is a very large example of the bow and
string girder, the span being 202 feet, and the height of the truss 23
feet. The trusses are three in number, for two lines of way, the middle
one being twice the strength of the outside trusses. The elevation of
the Windsor bridge is shown in fig. 2, Pl. IV. (p. 206). The bridge is
oblique to the river, being 20° off the square. To steady the arched
ribs sideways a system of diagonal bracing extends over the whole of the
top of the trusses, except at the ends, where headway has to be left for
the trains.
A section of the arched ribs and of the roadway girders in the centre of
one of the trusses is given in the woodcut (fig. 10). The arched rib, to
resist compression, is of triangular section.[99]
* * * * *
The borings to ascertain the nature of the ground at the foundations of
the piers were made in 1846, but it was not until 1848 that the works
were commenced. Each abutment consists of six cast-iron cylinders, 6
feet diameter, which were sunk by excavating the gravel from their
interior by hand dredging and by placing weights on the top so as to
force them down.
When each cylinder had been by this means sunk low enough to ensure a
good foundation, it was filled with concrete in the following manner. A
mixture formed of Thames ballast and Portland cement, in the proportions
of 8 to 1, was put into a canvas bag; this was lowered inside the
cylinder to the bottom, and, by pulling a rope, the mouth of the bag was
opened, and the concrete deposited under water in the bottom of the
cylinder. Whenever the work was interrupted, great care was taken before
recommencing it to clean off any deposit, in order that the new concrete
might adhere well to the old. When the cylinder had been filled to such
a height that there was no danger of its floating up when emptied, the
water was pumped out. The inside was then filled with concrete in the
ordinary manner. On the top were placed oak platforms, which support the
trusses of the bridge.
One of the outside trusses was tested at Bristol in July 1849, by
loading it gradually with iron rails, beginning from one end, until the
whole truss was uniformly weighted with 270 tons, or 1½ tons per
foot-run, observations on the deflection of different points of the
bottom girder being made both during the loading and unloading. The
results of this test were perfectly satisfactory.
The superstructure of the bridge was erected on scaffolding, and the
line was opened on October 8, 1849.
* * * * *
It will be desirable here to notice one or two important features in
this as in almost all Mr. Brunel’s bridges.
The ordinary permanent way was laid over the bridges with ballast of
sufficient thickness to enable the road to be kept in repair in the same
manner as the other parts of the line. As there was no change in the
nature of the support given to the rails, no concussion was caused on a
train entering or leaving a bridge. The ballast took off from the
structure the vibration of the train; and, in the event of carriages or
even engines getting off the line, it helped in a great measure to
prevent their ploughing through the flooring. Where the flooring was of
timber the ballast protected it from fire. Also in long bridges there
was no necessity for any contrivance of sliding rails to allow for the
effects on the structure of changes of temperature. On the other hand,
the ballast added to the weight on the bridge. With the timber viaducts
this was an advantage, since it kept the various parts of the framework
in close contact, and prevented sudden jars being brought on them by the
rapidly applied load of a passing train. Even on the large bridges the
cost of the extra material requisite to support the weight of the
ballast was more than compensated for by the advantages above referred
to.
Mr. Brunel employed timber flooring, as being the safest in the case of
carriages getting off the line, and also as being the cheapest. This
flooring in the iron bridges was generally laid diagonally on
wrought-iron cross girders, which were placed not at right angles to the
line, but obliquely, in order that the two wheels of the same axle of an
engine or heavy waggon might be on different cross girders at the same
time. By this arrangement the cross girders could be made of less
strength, and a saving effected in their cost and weight.
The bridge over the Wye at Chepstow, and the Royal Albert Bridge over
the Tamar at Saltash, are the largest and most important of Mr. Brunel’s
bridges.
They are remarkable not only for their dimensions, but also for the
economical character of the designs, the form of their superstructures,
and the methods by which the foundations of the piers were made.
At the part of the river Wye where it is crossed by the Chepstow Bridge,
a cliff of limestone rock rises on the left bank to a height of 120 feet
above the bed of the river, forming the precipitous edge of a broad
table-land; while on the right bank the ground slopes gently for a
considerable distance, rising only a little above high water, and is
composed partly of clay and partly of loose shingle interspersed with
large boulder stones. As it was necessary to leave a clear headway of 50
feet above high water for the navigation, the line on one side of the
river is on an embankment of great height, and on the other side it
penetrates the cliff about 20 feet below the top. The whole space to be
bridged over, 600 feet wide, was divided into a river span of 300 feet,
and three land spans of 100 feet each (see fig. 3, Pl. V. p. 206.) At
one end of the great span a secure abutment was offered by the cliff of
limestone rock; but at the other end, and under the piers of the smaller
spans, the ground throughout was soft, and full of water. There was,
however, rock at a depth of 30 feet below the bed of the river.
To reach this foundation with masonry, by means of a coffer dam, was
almost impracticable, as it was 84 feet below high water.
The plan of building a stone pier on a foundation of piles was
considered, and abandoned on account of the expense.
The method of sinking the cast-iron cylinders of the Windsor bridge has
been already described. The pneumatic process of sinking cylinders had
been introduced with great success at the Rochester bridge.
In this process the cylinder is closed at the top and air forced in by
pumps until the water is expelled at the bottom. Workmen in the interior
excavate the ground and remove any obstacles which prevent the cylinder
from sinking, weights being added to force it down. As the air within is
at high pressure, the workmen enter, and the materials are passed in and
out, through an intermediate chamber, called an ‘air lock,’ fitted with
air-tight doors. The pneumatic method was ultimately employed at
Chepstow, to assist in sinking the cylinders.
Before he decided on the plan for the foundations, Mr. Brunel had an
experimental cylinder made of cast iron, 3 feet in diameter, at the
bottom of which was an exterior screw flange 12 inches broad, and 7
inches pitch, making one complete turn. This screw cylinder penetrated
the ground like an ordinary screw pile. In one instance it was rapidly
sunk to a depth of 58 feet, through stiff clay and sand, in 142
revolutions;[100] yet, on another trial, when boulders were encountered,
there did not appear to be sufficient penetrating power. In one of these
trials, the screw, having got into a bed of running sand, had no hold,
and failed to descend. Mr. Brunel then had the cylinder partly raised,
and another screw added at some distance above the lower one. It was
then successfully screwed down.
Mr. Brunel, however, ultimately decided on forming the piers of
cast-iron cylinders forced down by loading and afterwards filled with
concrete, and the work was commenced in the spring of 1849.
With this form of construction all uncertainty of obtaining a secure
foundation was removed, as the pneumatic method was in reserve, in case
of excessive influx of water, to sink the cylinders to the rock, if it
could not be reached by simpler means; and additional cylinders could be
added, so as to obtain any amount of area of base that might be thought
necessary.
The land piers for the 100 feet spans consist each of three cylinders,
which are 6 feet in diameter, joined together in lengths of 7 feet. The
main pier, which supports one end of the great truss, consists of a
double row of cylinders, six in all, the lower parts of which are 8 feet
in diameter, joined together in lengths of 6 feet. The bottom of each
cylinder was made with a cutting edge, so as to penetrate the ground
easily.
Most of the cylinders were sunk by the process of excavating the ground
within them and weighting the top, the water being kept down by pumping.
As the ground consisted chiefly of wet sand and shingle, danger was
apprehended from its tendency to run in from the outside, while the
excavation was in progress. This would have diminished the lateral
stability of the cylinders; and great care was taken not to excavate too
near the bottom, but merely to loosen the ground round the cutting edge
and to force the cylinder down by weights. Stiff clay was sometimes used
to prevent the wet sand and gravel from being squeezed in from the
outside. When the cylinders had been sunk to the rock, and it had been
dressed off to form a level foundation, they were filled with concrete
in the same manner as at the Windsor bridge.
In sinking the cylinders of the main pier, much greater difficulties
were encountered than with those of the land piers, owing to large
boulders and pieces of timber being met with near the bottom. When still
at some distance from the rock, a length of one of these large
cylinders cracked, from its having met with an obstruction. Timber
struts were then fixed within it, until the obstacle was passed, when it
was strengthened by a strong wrought-iron hoop, and forced down to the
rock.
In April 1851, when the greater number of the cylinders had been sunk,
it was apparent that, from delays due to the influx of water and other
causes, some of them could not be completed by the time that the
superstructure would be ready. Mr. Brunel then decided to employ the
pneumatic method, and by means of this apparatus some of the remaining
cylinders were sunk. In the main pier four auxiliary columns, formed of
7-feet cylinders, were placed close to the others. They were connected
to the 8-feet cylinders by strong brackets, and supplied a great
additional bearing surface. Any slight inaccuracy of position in the
cylinders was corrected by adjusting cones at the level of the ground;
on these cones 6-feet cylinders were built up to the level of the
railway.
The depth to which the cylinders were sunk and their position are shown
in fig. 3, Pl. IV. From this drawing also the general form of the
superstructure will be understood.
The bridge is for two lines of way; each line is carried between two
longitudinal girders 7½ feet deep, of the section given in the woodcut,
fig. 11 (p. 208). Each girder has a triangular top flange with a plate
iron vertical web, and a slightly curved plate for the bottom flange.
The roadway girders over the three land spans of 100 feet are in one
piece, and are therefore continuous girders, 300 feet long, supported at
two intermediate points. Those across the main span are also 300 feet
long, and are supported by the main truss.
[Illustration: IRON BRIDGES]
The truss for each line of way consists of two suspension chains, one on
each side of the roadway, hung from either side of the ends of a
horizontal circular tube, arched slightly for the sake of appearance,
which rests on piers rising about 50 feet above the level of the rails.
The pier at the land end is of masonry, and the upper part of the middle
pier is of cast iron, resting on the cylinders already mentioned. Each
pier has two archways for the trains to pass through. The chains carry
the roadway girders at four points, and the tube is supported at two
intermediate points in its length by upright standards resting on the
chains. Thus, while the weight of the structure is supported somewhat in
the same manner as in a suspension bridge, the inward drag of the chains
is resisted by the tube. To prevent the framework from being distorted
by unequal loading, it is made rigid by diagonal chains connecting the
upper and lower ends of the two upright standards.
The main truss may be described as an inverted queen truss. The tube
which has to resist the compressive strain due to the inward pull of the
chains is 9 feet in diameter, and is made of boiler plate ¾ and ⅝ of
an inch thick, stiffened at intervals by diaphragms. The chains are like
those of suspension bridges, each formed of 12 and 14 links alternately,
these being 10 inches deep, and varying from ¾ to 11/16 of an inch
thick.[101]
At the ends of the tube, where the chains are connected to it, there are
several thicknesses of plate, between which the links of the chains are
introduced, and a round pin, 7 inches in diameter, passes through both
plates and links. The strain is thus conveyed from the chains to the
ends of the tube.
Though the trusses for the two lines of way are completely distinct,
the tubes are braced together horizontally, to increase their stiffness
sideways.
The woodcut (fig. 11) represents a transverse section of the truss for
one line of way, and shows the circular tube with the internal
diaphragms, the upright standards which support it, the roadway girders,
and the chains.
[Illustration: _Scale of feet._
Fig. 11. Truss of Chepstow Bridge.
_Transverse Section._]
In consequence of the great depth of the truss, which is about 50 feet,
or one-sixth of the length, the strains on the several parts are
comparatively small for such a large span.
The weight of wrought-iron work in each of the trusses of the main
opening is 460 tons, inclusive of the longitudinal and cross girders,
which weigh 130 tons.
At the points where the roadway girders are intersected by the inclined
chains, they are not fixed to the chains, but rest upon them, rollers
and saddles being placed between; and at the ends of the short
horizontal links, in the middle of the span, there are screws for
adjusting the level of the girders.
These arrangements were made in order that the roadway girders might not
be strained by the slight alteration in the form of the truss which
takes place when a load comes on the bridge.
The continuous roadway girders were, in the case of the large span,
supported at six points, and in those over the three land spans at four
points. As the strains on continuous beams, supported at so many points,
had not at that time been fully investigated, Mr. Brunel had the
subject carefully enquired into both by calculation and experiment, and
was thus enabled to proportion the section of the girders to the strains
at each point in their length. Some account of this investigation is
given in the note at the end of this chapter.
As soon as the ironwork for the first truss was completed, it was put
together parallel to the river bank close to the site of the bridge. The
ends were supported on temporary piers, and the structure was uniformly
weighted with a load of 770 tons, or 2¾ tons per foot run. In unloading
it, the weight was taken off from one end of the truss, so as to test
its strength when unequally loaded. The testing having been
satisfactorily completed, the truss was taken to pieces, and
preparations were made for erecting it.
It was necessary that the river traffic should not be interrupted for
any long period; this circumstance materially influenced the nature of
the design of the superstructure, which was such that no scaffolding was
required in its erection, nor was there any interference with the
navigation for more than a single tide. The truss was made so that it
could be divided into parts, each of which could be lifted separately
and quickly. For the operation of lifting Mr. Brunel determined to use
chain purchases worked by crabs.[102] The tube was temporarily stiffened
by portions of the main chains, arranged so as to form a truss. With
this assistance it was able to carry its own weight when suspended by
the two ends.
The preliminary operation of slewing the tube to its position on a
platform at right angles to the river, was a work requiring a good deal
of careful contrivance. When this had been accomplished, a pontoon,
consisting of six wrought-iron barges, was placed opposite the end of
the tube, and all was ready for floating it across the river.
The floating took place on Thursday morning, April 8, 1852. The tube had
been rolled forward on two trucks till its end overhung the pontoon;
and, as the tide rose, the pontoon floated with the end of the tube
resting on it. In order to guide it in a straight line across the river,
hawsers were attached to points on the bank up and down the stream, and
were led to crabs on the pontoon, so that by hauling on either hawser
the tube was kept in its right course. As spring tides at Chepstow rise
40 feet, there is a rapid current except for a very short time.
The operation of drawing the tube across was commenced at a little after
nine o’clock, and by a quarter to ten the pontoon had reached the other
side safely, and the tube spanned the river. All proceeded with perfect
quiet and regularity under the management of Mr. Brunel, who was
assisted by Mr. Brereton and Captain Claxton. As soon as the pontoon
reached the further shore, the chains of the lifting tackles were
attached to the tube. The tube was lifted in the course of the day to
the level of the railway, and afterwards to its place on the top of the
piers, when the suspension chains and the rest of the truss were
attached to it. The bridge was opened for a single line of way on July
14, 1852. The second tube was floated in a similar manner to the first,
and the bridge was completed shortly afterwards.
The total cost of the Chepstow bridge was 77,000_l_.[103]
* * * * *
The Royal Albert Bridge, which carries the Cornwall Railway across the
River Tamar at Saltash, is the last and greatest of Mr. Brunel’s railway
works.
A railway into Cornwall, crossing the river Tamar, was proposed as early
as 1844. Mr. Brunel at one time thought of carrying the trains across on
a steam ferry similar to those which had been successfully introduced by
Mr. Rendel.
In 1845 a company was formed and an application made for an Act to
construct the railway either with a steam ferry at Torpoint or by a
bridge at Saltash. The latter plan was sanctioned by Parliament.
The height of the line shown on the section at the crossing of the Tamar
was 80 feet above high water. The Admiralty, however, required that this
height should be increased. No further steps were taken till the
beginning of 1847, when some preliminary borings and sections were made,
in order to prepare definite plans for the bridge. The facts then
ascertained were so encouraging as to strengthen Mr. Brunel in his
opinion that the difficulties to be encountered would not be found
greater than had been anticipated.
The river at Saltash is 1,100 feet wide, with a depth in the middle of
about 70 feet at high water. It had at first been intended to construct
the bridge with one span of 255 feet, and six of 105 feet, with
superstructures of timber-trussed arches.[104] In compliance with the
requirements of the Admiralty, the design was altered to two spans of
300 feet, and two of 200 feet, with a clear headway of 100 feet. This
arrangement would have required three piers in deep water. Mr. Brunel
subsequently decided to have only one pier in deep water, and to have
two spans of 465 feet each. It was afterwards found that these could be
reduced to 455 feet.[105]
Twenty years before, while engaged with his father on the Thames Tunnel,
he had conceived the idea of working under a diving-bell of great
dimensions. Sir Isambard approved of the suggestion, and thought of
applying it in sinking the shafts of the Tunnel. Drawings were prepared,
but the circumstance of a patent for a similar idea having been taken
out by Lord Cochrane partly deterred him from carrying out the project,
though some sketches were afterwards made for constructing a lighthouse
by means of this arrangement. When the construction of the Cornwall
Railway had to be considered, Mr. Brunel thought that his old idea would
be applicable to the difficulties to be encountered at Saltash.
Although the plan of using a large diving-bell was one which was nearly
certain to be successful, Mr. Brunel thought it probable that a large
cylinder of wrought iron could be constructed to serve as a coffer-dam,
and that after sinking it through the mud, the bottom edge might be
sufficiently water-tight to admit of the water being pumped out, and the
masonry of the pier built in the ordinary manner.
A trial cylinder, 6 feet diameter and 85 feet long, was made, partly to
ascertain whether or not this plan was practicable, but mainly for the
purpose of thoroughly examining the site of the centre pier, where the
surface of the rock was 80 feet below high water.
A strong framework was fitted on two gun-brig hulks, with powerful
tackle for lowering and raising the cylinder. After it had been lowered
to the bottom, five borings were taken within it, reaching through the
mud to the rock. The cylinder was then shifted and similar borings made.
The positions of the borings, one hundred and seventy five in all, were
carefully recorded; and thus a minute and accurate survey was obtained
of the surface of the rock. The site of the pier was afterwards
determined by means of a model constructed from these observations. In
January 1849, when sufficient information had been obtained, the water
was pumped out of the trial cylinder, and the mud excavated down to the
rock. A short piece of masonry was then built, to demonstrate the
practicability of building a pier in such a situation.
The expenditure of the Company for works of all kinds was shortly
afterwards curtailed as much as possible, and no further progress was
made for upwards of three years. However, information had been gained
which proved that a masonry pier could be built in the middle of the
river, on a good rock foundation which was there covered by a thickness
of about 16 feet of mud.
During the suspension of the works, all the plans were revised, with the
view of reducing the first cost wherever practicable; and Mr. Brunel
decided not to make the bridge for a double line, even if there were
money forthcoming to do so. His reason for this is given in the
following report to the Board of Trade, made in 1852:--
This bridge had been always assumed to be constructed for a double
line of railway as well as the rest of the line. In constructing
the whole of the line at present with a single line of rails,
except at certain places, the prospect of doubling it hereafter is
not wholly abandoned, but with respect to the bridge it is
otherwise.
It is now universally admitted that when a sufficient object is to
be attained, arrangements may easily be made by which a short piece
of single line can be worked without any appreciable
inconvenience.... This will make a reduction of at least
100,000_l._
In the summer of 1852 the designs of the bridge were matured, and by the
beginning of 1853 the Admiralty had approved of them; the work of
constructing the great cylinder for the centre pier was then commenced.
It was determined to provide for the possibility of having to employ the
pneumatic process. The cylinder had a diameter of 35 feet at the
bottom, and about 20 feet above the lower end of it a dome was made to
form the roof of the diving-bell; from the centre of the dome rose a
tube 10 feet in diameter to the level of the top of the great cylinder.
As a diving-bell of this size, under 80 feet of water, might have proved
unmanageable, an annular space, forming a gallery or jacket of 4 feet in
width and 20 feet high, was formed round the inner circumference of the
bottom of the cylinder below the dome. This annular space was divided by
radial vertical partitions into eleven compartments, and was connected
at the top by an air-passage with a 6-foot cylinder, which was placed
eccentrically inside the 10-foot cylinder already mentioned, and served
as a communication between the outside and the annulus. On the top of
the 6-foot cylinder were placed the air-locks of the pneumatic apparatus
which had been used at Chepstow. Thus air might be pumped into the
annular space, the water expelled, and the work carried on without
having to use air pressure under the whole of the dome. In that part of
the 10-foot cylinder which was not occupied by the 6-foot cylinder a
powerful set of pumps were fixed to keep down the water in the central
space, and diminish the pressure under which the men worked, thus
utilising whatever advantage could be gained from the great cylinder
acting as a coffer-dam. As it had been ascertained that the surface of
the rock dipped to the south-west to the extent of about 6 feet in the
width of the pier, the bottom of the cylinder was made oblique, so as to
fit the surface of the rock. These arrangements are represented in the
transverse section of the great cylinder (Pl. V. p. 218).[106]
The great cylinder, having been constructed on the river-bank, was moved
down to low water on launching-ways, and floated off by the rising tide.
Guided between four pontoons, it was finally sunk in correct position in
June 1854.
Some delay in penetrating the mud was caused by a bed of oyster shells,
which had to be cut through by one edge of the cylinder. In consequence
of some irregularities of the surface of the rock, the cylinder at first
deviated considerably from an upright position; and it was necessary to
use the pneumatic apparatus to gain access to the rock, and excavate it.
The height of the annulus below the dome was such that it was not quite
filled by the mud when the cylinder rested on the bottom. The work of
getting the mud out of the annular space was much facilitated by the
division of it into compartments.
By February 1855, the cylinder had been sunk to its full depth in an
upright position, and it then rested everywhere on the rock, its lowest
point being 87 feet 6 inches below high water.
Much trouble was given by a spring of water issuing out of a fissure in
the rock, in one of the compartments, but the flow was stopped by
driving close sheet piles into the fissure. The rock in the annulus was
dressed, and the space filled by a ring of granite ashlar masonry which
was built to a height of about 7 feet all round. The state of the work
at this time is that represented in the section of the cylinder, (Pl. V.
p. 218).
The rock consisted of greenstone trap, so hard that tools could with
difficulty be got to work it. When the ring of masonry was completed, it
was expected that the bottom might be sufficiently water-tight to act as
a coffer-dam, and allow of the mud being taken out from the central part
of the cylinder, below the dome. But the pumping power was not at first
sufficient for this purpose, and it was thought that it would be
necessary to employ the pneumatic process in this space also.
However, by rapid and incessant pumping the water was lowered so as to
allow of the mud and rock being excavated, and the masonry in the
central space built without having again recourse to the use of air
pressure. The leakage water was conveyed to two wells, formed of
cast-iron pipes built into the masonry, from which the water was pumped.
The inner plates of the annulus were cut out, and the work in the centre
which consisted of granite ashlar set in cement was thoroughly bonded
into the ring of masonry already built. When the work was carried up to
the level of the dome, both the dome and the internal 10-foot cylinder
were cut out and removed. When the building had been carried up some
height, the pump wells were filled with cement concrete, and the influx
of water stopped. Finally, about the end of 1856, when the masonry was
completed to the cap of the pier, the upper part of the great cylinder
was unbolted and taken ashore, it having been made in two halves with
that object. Thus the most difficult part of the undertaking was
successfully completed.[107]
The centre pier of the Saltash bridge is, like many great engineering
works, out of sight, and little regarded by any but professional men.
The rest of the bridge forms a striking feature in a beautiful
landscape, and its appearance is well known.
The whole length of the bridge is about 2,200 feet, and is divided into
two great spans over the river of 455 feet each and seventeen side
spans, varying from 70 to 90 feet, which are on sharp curves. The piers
of the side spans, as well as the two large piers carrying the land ends
of the main trusses, are of masonry. The masonry of the centre pier is
35 feet in diameter, and is carried up about 12 feet above high water
level. On it stand four cast-iron octagonal columns, rising up to the
level of the railway. The piers which support the ends of the great
trusses are constructed with arched openings, through which the trains
pass.
The transverse elevation of the centre pier (Pl. V.) shows the octagonal
columns connected by cast-iron open-work, and the arched opening. The
upper part of the centre pier is a cast-iron standard, and that of the
land piers is of masonry cased with cast iron.[108]
The elevation shows the great height of the structure, the rails being
190 feet and the highest part of the truss 260 feet above the lowest
point of the foundations.
The railway is carried over each of the smaller openings between two
longitudinal girders, and over the main spans it is carried between
similar longitudinal girders, which are suspended at intervals from the
main truss.
[Illustration: THE ROYAL ALBERT BRIDGE]
Each truss consists of a wrought-iron oval tube, which forms an arch,
and of two suspension chains,[109] one on either side of the tube,
connecting its two ends. The rise of the arched tube above its
abutments on the top of the piers is the same as the fall of the
suspension chains below the same level. At eleven points in the length
of the truss the chains are connected to the tube by upright standards,
which are braced together by diagonal bars, in order to resist the
strains due to unequal loading. The roadway girders are suspended from
the truss at the upright standards already mentioned, and at an
intermediate point between each of them.
The truss has the great depth of 56 feet in the centre; this conduces
materially to the economy of the construction, as it diminishes the
strain upon the principal parts, the tube and the chains, and so enables
them to be made of smaller dimensions.
[Illustration: Fig. 12. Truss of Saltash Bridge.
_Transverse section._
_Scale of feet._]
The woodcut (fig. 12) is a transverse section in the centre of the
truss, showing the oval tube, the chains, the upright and standards, the
roadway girders.
The tube is made oval in section with the greater diameter horizontal,
in order that it may have stiffness sideways under the compressive
strain, and that the main chains may hang vertically at such a distance
as to leave room for the roadway between them. The tube is 16 feet 9
inches broad and 12 feet 3 inches in height. Each chain consists of two
tiers of links, each tier formed of 14 and 15 links alternately. These
are 7 inches deep and about 1 inch thick. The arrangements of the
ironwork of the tube and its connections with the main chains are
generally similar to those at Chepstow.
The truss may be described as a combination of an arch and a suspension
bridge, half the weight being placed on the one and half on the other,
the outward thrust of the arch on the abutments being counterbalanced by
the inward drag of the chains.
The mechanical arrangement of the Saltash truss is similar to that of
the one at Chepstow.[110] The tube, resting on standards, the railway
passing beneath, the suspension chains hung from either side of the
tube, the upright standards, and the diagonal bracing are common to the
two structures.
The difference in the form of the two trusses is principally the result
of the difference in the circumstances attending the construction of the
bridges at Chepstow and Saltash. The design of the Chepstow truss was
chiefly determined by the necessity of lifting up the separate parts of
it under conditions of peculiar difficulty; while at Saltash the mode of
floating and lifting the superstructure had great influence in the
preparation of the design.
On Plate V. (p. 218) is given an elevation of one span of the Saltash
bridge, and a general elevation on a smaller scale of the whole bridge.
The total weight of wrought ironwork in the superstructure of each span
is 1,060 tons.[111]
The trusses at Saltash were not lifted in parts, as at Chepstow; for,
as the river was divided by the centre pier into two openings, one of
them could be left clear for the navigation, and each truss, with its
roadway girders attached, could be raised to its position slowly and in
one piece. The trusses were constructed parallel to the river on the
Devonshire side, close to the site of the bridge. When the truss for the
Cornwall or western span was completed, temporary piers were erected to
support the ends, and the scaffolding having been removed, the roadway
was loaded with 1,190 tons, uniformly distributed.[112]
This test having proved satisfactory, preparations were made for
floating the truss. Docks were made underneath it near the two ends, and
in each of these docks two iron pontoons were placed. Valves were then
opened to admit water, and the pontoons were allowed to sink on timbers
prepared to receive them.
Upon each pair of pontoons was erected an elaborate framework of timber
to carry the weight of half the truss, or between 500 and 600 tons. The
framework consisted of stout timber props, some of them 40 feet long,
extending from the pontoon to the arched tube, and was attached to the
tube by iron suspension rods, so that when the operation of floating was
completed, the pontoons would be free to pass from underneath the truss.
* * * * *
Mr. Brunel had previously taken part in operations of this nature. When
Mr. Robert Stephenson was about to undertake the floating of the tubes
of the Conway and Britannia bridges, he asked his friends Mr. Brunel
and Mr. Locke to give him their assistance. They were present at all, or
nearly all, these difficult operations, and Mr. Brunel had an active
share in the work, especially in the floating of the first Conway tube.
By Mr. Brunel’s advice Mr. Stephenson had obtained the services of
Captain Claxton to superintend the nautical part of the work; and
Captain Claxton was, as a matter of course, with Mr. Brunel in a similar
capacity at Chepstow and Saltash.
At Saltash fortunately there was not so swift a tide as there had been
at the Britannia and Conway floatings.
In order to haul the truss out, warps were laid from the pontoons to a
gun-brig hulk near the centre pier, and to a barge higher up the river.
On this barge were also placed ready for use the ends of four warps,
leading to capstans and crabs on board vessels moored at various points.
To keep the truss from being drifted up or down the river while being
moved out, radius lines were laid from the pontoons to moorings, with
arrangements for hauling in on them if required.
In order to ensure his directions being clearly understood and promptly
attended to, Mr. Brunel assembled a number of his assistants, one of
whom was placed as ‘Captain’ in each of the vessels containing the
hauling capstans, to superintend the men, and to execute orders. These
orders were given by signals.
It was most important that the attention of the captain should not be
diverted by looking out for the signals, and that there should be no
chance of a signal not being seen by him because he was attending to
some other of his duties. There was, therefore, in each vessel an
assistant whose sole duty it was to watch for the signals, to give the
appropriate interpretation to the captain, and to acknowledge the signal
by a flag corresponding to that by which it was given.
Mr. Brunel directed the operations from a platform in the centre of the
truss. The signals were given from a smaller platform immediately above,
and were made by red and white flags, held in front of black boards,
which were turned towards the vessel signalled to. Printed papers
containing instructions were distributed to all engaged; the signalling
was carefully rehearsed, as also was every other part of the operations
which could be tried beforehand.
* * * * *
September 1, 1857, was the day fixed for the floating. During the
morning, the men, about 500 in number, assembled at their stations on
the vessels and pontoons. Captain Claxton had command of the
arrangements afloat, and as a reserve force to act in any emergency
several boats were lent from H.M.S. ‘Ajax’ and the Dockyard. With Mr.
Brunel were Mr. Brereton and Captain Harrison, the commander of the
‘Great Eastern.’ Mr. Robert Stephenson was expected, but a serious
attack of illness prevented him from being present.
At about one o’clock in the afternoon signals from the tops of the
temporary piers on which the truss rested, showed that the ends had been
lifted three inches clear. Mr. Brunel then gave the signal for the men
in the pontoons to haul on the warps, and the great structure glided
slowly out to the centre of the river. A pause was then made, while the
warps which were to swing the truss round into its place were being
attached to the pontoon which was farthest from the centre pier. When
this was done, the different ropes were hauled upon in obedience to
signals, so as to keep the other pontoon close to the centre pier, upon
which, as a pivot, the truss swung round in a quarter circle till it
occupied the whole of the western half of the river, and was brought
close to its appointed resting-place. It was finally adjusted to its
exact position by strong tackles attached to the piers. Water was then
admitted into the pontoons; and, as the tide fell, they were allowed to
drift away, leaving the truss resting on the piers, the roadway girders
being but a few feet above the water.
The whole operation was conducted with the most perfect order and
regularity. The beauty of the scenery and the changing effect produced
by the truss in the various positions it assumed as it was being moved
forward and swung round into its place, rendered the operation as
interesting to the spectators as its results were satisfactory to Mr.
Brunel and to those who assisted him.[113]
* * * * *
In the task of lifting the truss, as well as in that of floating it, Mr.
Brunel had the great advantage of the experience gained at the Britannia
Bridge. There the piers were built first, and the tubes hauled up with
link chains by hydraulic presses placed on the tops of the towers. The
design of the piers at Saltash did not allow of this plan being adopted,
and they were built up under the truss as it was lifted. Under each end
of the truss were three hydraulic presses; the two outside presses
combined, or the middle one by itself, were sufficient to lift the
weight. Mr. Brunel had also at first intended to have strong
screw-jacks, which were to be kept screwed up underneath the truss, and
so to support the weight, if by any accident the presses failed. A
modification of this plan was adopted; the rams of the presses had a
screw thread cut on them, and a large nut on each was kept screwed up
hard against the top of the press as the ram emerged from it. As an
additional precaution, timber packing, in thin layers, was placed in the
space between the completed portion of the pier and the end of the truss
as it was lifted. Great care was thus taken to guard against any mishap.
The tube was lifted 3 feet at a time at each end. The operation went on
slowly, in order to allow the masonry of the land pier to set after it
had been built up underneath the truss. The work was carried on with
great system and care under the immediate superintendence of Mr.
Brereton. Mr. Brunel was only able to be present during one of the
lifting operations, as he was then engaged in the launch of the ‘Great
Eastern.’
* * * * *
By July 1858, the first truss had been lifted to its full height, and
the second truss was ready for floating. The arrangements were generally
similar to those on the previous occasion; the course, however, to be
traversed by the pontoons was more intricate than on the previous
occasion, as the land pier on the Devonshire side of the river, over
which the first truss had passed, had been built up to receive the end
of the second.
This truss had, therefore, to be moved first outwards till the pontoons
were clear of the docks, then it had to move endways up the river, and
to swing round into position. Mr. Brunel was obliged to remain abroad
from ill-health, and Mr. Brereton conducted the operations. Although the
weather was not favourable, and the wind high, the truss was safely
landed on the piers; and was afterwards raised in the same manner as the
first one.[114]
The general elevation, Plate V., shows the proportions of the bridge. On
the Devonshire side, the side spans pass over fields, and on the
Cornwall side over the town of Saltash.
The general effect of the bridge is in no way heightened by an
expenditure of money on architectural ornament; for, with the exception
of a few unimportant mouldings, the bridge is absolutely unadorned. The
total cost was 225,000_l._--a very moderate expenditure, especially when
the difficult work at the centre pier is taken into account. This result
is due not only to the careful manner in which all the details of the
design were prepared, but also to the great attention given throughout
to the construction.
His Royal Highness the Prince Consort, as Lord Warden of the Stannaries,
permitted the bridge to be called the Royal Albert Bridge, and consented
to open it in person. The ceremony was performed on May 3, 1859. Mr.
Brunel was compelled to be absent on the Continent, for the sake of his
health, and was represented on the occasion by Mr. Brereton.
After Mr. Brunel’s return to England, he paid a hurried visit to the
Cornwall Railway, and, for the first and last time, saw in its completed
state the great work on which he had expended so much thought and care.
NOTE, (pp. 182, 194, 209).
_Experiments on Matters connected with Bridge Construction._
No account of the structures designed by Mr. Brunel would be complete
without a reference to the elaborate care he always took, wherever it
was practicable, to satisfy himself by experiment of the qualities of
the materials employed, and of the correctness of the principles
followed. It would not here be possible to give a detailed record of all
his experiments, but an account of some of the methods employed by him
will be interesting.
Some of the larger of Mr. Brunel’s experiments on cast and wrought-iron
girders have already been mentioned.[115] He scarcely ever made any
large girder or framework without having it fully tested, and he made
extensive and elaborate experiments, most of them on a very large scale,
on the strength of some of the materials and component parts of his
different structures.
Among the large scale experiments tried by Mr. Brunel, were those on the
compressive strength of yellow pine-timber, which were made at Bristol
in 1846, and were on specimens from 10 to 40 feet in length, and from 6
to 15 inches square. A framework of four upright pieces of whole timber,
nearly 50 feet high, contained four strong bars of wrought iron, placed
vertically, and attached at their lower ends to the cylinder of a
hydraulic press. Along these bars, a casting could be moved, and
fastened at different heights by keys, in such a manner as to have its
under-surface, which was planed, perfectly horizontal. The ends of a
specimen having been made exactly square to its length, it was put in
this apparatus, with the upper end bearing against the lower surface of
the movable casting, and the lower end resting on the top-surface of the
ram of the hydraulic press, which was also planed and adjusted so as to
be horizontal. The keys, which attached the movable casting to the bars,
were now driven tight, and the pump of the press worked, weights being
placed on the end of the lever, to correspond with increments of
pressure on the ram. These weights were added gradually, until the
specimen gave way. The accuracy of this mode of measuring the pressure
was tested by direct loading of the ram with rails, which was repeated
several times during the course of the experiments, so as to guard
against any change in the amount of friction of the press. For each
increment of weight, the compression of the specimen was measured on its
four faces, and its deflection, or amount of bending, on two adjacent
faces. The transverse stiffness of long specimens was also tried, by
supporting them at each end, and loading them in the middle. The
deflection in the middle thus observed corresponded very closely with
what might have been expected from the observations on the direct
compression; and from the constants so obtained, the strength of those
specimens, whose length was very great as compared with their transverse
dimensions, could be obtained by Euler’s theory, but for the stouter
specimens the strength per square inch was found to be nearly constant.
From these experiments, a complete practical knowledge of the properties
of yellow pine timber, when subjected to end pressures, was obtained,
knowledge new at the time, and almost essential to Mr. Brunel in
designing the many viaducts which he afterwards constructed.
Mr. Brunel also made experiments on the strength of pine timber when
exposed to pressure on the side or at right angles to the fibre. By this
means he determined the area which it was desirable to provide for the
washers of bolts, and the weight which might safely be placed on
transverse timbers or sills of viaducts.
Mr. Brunel’s experiments on riveting were also important. Most of these
were made with specimens 20 inches wide, and half an inch thick. They
were compared with specimens of solid iron, of the same quality and
thickness as the riveted specimens, and also the same width minus the
rivet holes, so as to have equal efficient sectional areas. Double
covering plates and double riveting were used in all cases, the
variation being in the widths of the covering plates, and the number and
arrangement of the rivets. The experiments were continued until thirty
in all had been made, and the strongest form of joint was considered to
have been arrived at.
In connection with the lifting of the parts of the Chepstow Bridge, an
elaborate series of experiments was made on ropes, chains, and
wire-rope, so as to ascertain which of these it was desirable to employ,
as possessing the greatest advantages. The experiments made were of two
kinds, one to determine the absolute strength of the specimen when
subjected to a straight pull, and the other to observe what took place
when it was worked over a sheave. In the first set the specimen was held
at each end in the jaws of a pair of wrought-iron clamps, which were
tightened up by means of screws. One of the clamps was attached to a
fixed beam, and from the other was suspended a large cylindrical tank,
which was gradually filled with water until the specimen gave way, the
breaking strain being the weight of the tank and water. This weight was
ascertained by actual weighing with a steelyard when the water in the
tank was at different heights. Observations on the extension, shrinkage
of the circumference, and change in the pitch of the spiral of the rope
were made with different loads, and the strength of a sufficient number
of the yarns of which the rope was composed was tried to ascertain the
loss of strength by combining the yarns into a rope. In the second set
the specimen, clamped as before, was passed over a sheave, the axle of
which rolled horizontally on planed cast-iron plates, in order to
diminish friction. To each clamp was attached a cylindrical iron tank.
Water being admitted to the highest tank until downward motion
commenced, its influx was stopped, and the tank descended, the other one
rising. Water was then admitted to the now highest tank until motion
again commenced, and this process was repeated until the specimen gave
way, the tanks getting fuller of water at each movement, at which times
the difference of weight of the two tanks was observed. This, minus the
slight friction of the apparatus, represented the rigidity of the rope.
The extensions were observed as in the first set of experiments.
The specimens consisted of hemp, manilla, shroud laid and hawser laid
ropes, from 8 to 10 inches in circumference, round and flat wire ropes,
and chains of different sizes of about the same strength as the ropes.
The sheaves also were of different diameters. These experiments resulted
in Mr. Brunel deciding to use chains for lifting the bridge, and this
mainly from the circumstance that chains work more satisfactorily over a
sheave than either hemp or wire ropes.
Some small scale experiments made by Mr. Brunel are deserving of notice.
These were made to verify calculations on the longitudinal girders of
the Chepstow truss, which are virtually continuous beams of five unequal
spans. It was desirable to test the results of analysis by experiment,
in order to be assured that no errors had been committed in its
application. Mr. Brunel accordingly devised the following simple form of
experiment for this purpose. A deal rod, exactly half an inch square and
38 feet long, quite free from knots, was supported on props of equal
height, above the perfectly horizontal and planed surface of a large
beam of timber. The props were placed so as to correspond relatively to
the actual spans, and the rod was loaded uniformly by means of a chain.
It was thus bent into an elastic curve, the ordinates of which were very
carefully measured, at every foot along the length, by a finely divided
scale and magnifier. The pressure on each prop was also determined, by
removing any particular one, and suspending the point of the rod
immediately over it to a steel-yard, the weight being observed when the
point of the rod was exactly at the same level as before the prop was
removed. The obvious condition, that the sum of the pressures on the
props should be equal to the weight of the rod and its load, furnished a
satisfactory means of testing the results of these weighings. The rod
being turned over on each of its four sides, the experiments were
repeated, and the average taken, in order to eliminate the effects of
initial curvature, or of unequal elasticity. Diagrams of the elastic
curves were then made, showing the correspondence of theory with
experiment, and this was so close as to leave no doubt that a true
knowledge of the nature of the strains had been arrived at. One of these
diagrams is given by Mr. Edwin Clark in his work on the ‘Britannia and
Conway Tubular Bridges,’ vol. i. p. 462.
By modifications of the plan Mr. Brunel adopted in this experiment, the
strains on continuous beams of varying section may be ascertained with
considerable accuracy.
CHAPTER VIII.
_STEAM NAVIGATION. THE ‘GREAT WESTERN’ STEAM-SHIP._
A.D. 1835--1847. ÆTATIS 30--42.
INTRODUCTION TO THE CHAPTERS ON STEAM NAVIGATION--FORMATION OF THE
GREAT WESTERN STEAM-SHIP COMPANY--COMMENCEMENT OF THE BUILDING OF
THE ‘GREAT WESTERN’--REPORT ON SELECTION OF THE BUILDERS OF THE
ENGINES (JUNE 18, 1836)--STATEMENTS OF DR. LARDNER ON THE PROBABLE
FAILURE OF A LINE OF STEAM-SHIPS BETWEEN ENGLAND AND
AMERICA--VOYAGE OF THE ‘GREAT WESTERN’ TO LONDON--COMPLETION OF THE
ENGINES--HER RETURN TO BRISTOL--FIRE ON BOARD AND ACCIDENT TO MR.
BRUNEL--VOYAGE TO NEW YORK--COMPARISON BETWEEN THE PERFORMANCES OF
THE ‘GREAT WESTERN’ AND THE ‘SIRIUS’--SUBSEQUENT HISTORY OF THE
‘GREAT WESTERN’--NOTE: DIMENSIONS OF THE SHIP AND ENGINES.
It will readily be conceded that Mr. Brunel’s railway works, which have
formed the subject of the five preceding chapters, would have given him
ample employment for the thirty years of his professional life.
Nevertheless, during almost the whole of that period--namely, from 1835,
the year of the passing of the Great Western Railway Bill, to his death
in 1859--he was also engaged in the accomplishment of undertakings which
had for their object the systematic development of Ocean Steam
Navigation.[116]
The ‘Great Western,’ the first steam-ship which made regular voyages
across the Atlantic, the ‘Great Britain,’ the first large iron
steam-ship, and the first large ship in which the screw propeller was
used, and, lastly, the ‘Great Eastern,’ were Mr. Brunel’s works, built
under his direction, in the midst of his other engrossing occupations,
and at the sacrifice of his health and life.
The history of these projects will contain records of many
disappointments as well as of success; for no great and novel
undertaking can be perfected at once and without changes of plan and
arrangement. As engineer to the Companies which built these steam-ships,
Mr. Brunel advised the adoption of measures strongly in opposition to
current popular opinion, and far bolder and more daring than even his
recommendation of the broad gauge and the atmospheric system. The
results obtained have verified his calculations, and the conclusions he
sought to establish are now so generally accepted that it is difficult
to believe that they were ever questioned. No one now has any doubt that
large vessels can with safety be built of iron, or that the screw
propeller can be advantageously employed in ships of war and the
mercantile navy; no one can now deny that it is practicable for
steam-ships to make long voyages across the ocean with regularity and
speed.
* * * * *
A detailed account will now be given of the ships whose performances
first demonstrated the truth of these propositions.
Although the ‘Great Western’ was the first steamer which was built for
regular voyages between Europe and America, the first attempt to use
steam in the direct voyage across the Atlantic was made by an American
ship of 300 tons burden, called the ‘Savannah,’ and built at New York.
Her engines were of small power, with paddles made to ship and unship.
She made only two voyages to and from Europe: in the first of these she
left the port of Savannah on May 25, and anchored at Liverpool on June
20, 1819.
No further advance in Ocean Steam Navigation seems to have been
attempted until 1835. In the October of that year, at a meeting of the
Directors of the Great Western Railway Company, at Radley’s Hotel, in
Bridge Street, Blackfriars, one of the party spoke of the enormous
length, as it then appeared, of the proposed railway from London to
Bristol. Mr. Brunel exclaimed, ‘Why not make it longer, and have a
steamboat to go from Bristol to New York, and call it the “Great
Western?”’ This suggestion was treated as a joke by most of those who
heard it; but at night Mr. Brunel and Mr. T. R. Guppy, one of the
Directors, talked it over, and afterwards consulted three of the leading
members of the Board--Mr. Scott, Mr. Pycroft, and Mr. Robert Bright.
They took up the idea warmly, and a committee was formed to carry out
the project.
As a preliminary measure, Mr. Guppy and Captain Christopher Claxton,
R.N., made a tour of the great ship-building ports of the kingdom, in
order to collect information. The results of their inquiries were
embodied in a report, dated January 1, 1836, which describes at great
length the advantages to be gained in large vessels. The manuscript was
submitted to Mr. Brunel previously to its publication, and he inserted
the following passage:--
The resistance of vessels in the water does not increase in direct
proportion to their tonnage. This is easily explained; the tonnage
increases as the cubes of their dimensions, while the resistance
increases about as their squares; so that a vessel of double the
tonnage of another, capable of containing an engine of twice the
power, does not really meet with double the resistance. Speed
therefore will be greater with the large vessel, or the
proportionate power of the engine and consumption of fuel may be
reduced.
This was an important addition to the report, for it enunciates the
principle which governed Mr. Brunel in determining the dimensions and
power, not only of the ‘Great Western,’ but also of the ‘Great Britain’
and ‘Great Eastern’ steam-ships.
Immediately after the publication of this report a Company was formed in
Bristol called ‘The Great Western Steam-Ship Company,’ Mr. Peter Maze
being the Chairman, and Captain Claxton the Managing Director. Captain
Claxton’s exertions in the service of the Company from its formation to
its dissolution were unremitting and invaluable. He was also, from the
date of Mr. Brunel’s first connection with Bristol, one of his most
intimate friends, and his confidential adviser on all points on which
nautical experience was of value.[117]
Mr. Patterson (an eminent ship-builder of Bristol) was selected to
superintend the building of the first ship, under the direction of a
‘Building Committee’ consisting of Captain Claxton, Mr. Guppy, and Mr.
Brunel. Whenever railway business called Mr. Brunel to Bristol, which at
this time was at least once in every week, the Committee and Mr.
Patterson used to meet at the office, or at Captain Claxton’s or Mr.
Guppy’s house, and often sat far into the night discussing the details
of the design of the ship.[118]
One of the most important questions which occupied Mr. Brunel’s
attention was the selection of the builders of the engines. Tenders were
invited; and on receiving them, he addressed the following report to
Captain Claxton, the Managing Director:--
June 18, 1836.
In considering the three tenders for the supply of marine engines
for your first vessel, which you have submitted to me for my
opinion, I have assumed that the interests of the company are
paramount, and that all feelings of partiality towards any
particular manufacturer or any local interest must yield to the
absolute necessity, in this the first and the boldest attempt of
the kind yet made, of not merely satisfying yourselves that you
will obtain a good engine, but also of taking all those means of
securing the best which in the eyes of the public may be
unquestionable. In this view of the case, if you agree with me, I
think you will consider that, provided the prices are fair
individually, the relative amount of the tenders is a secondary
consideration.
I assume, also, that the high respectability of all these parties
would ensure equally from either the best materials and
workmanship, and I shall confine myself simply to pointing out a
few of the conditions peculiar to the engines which you require,
and the means which the different parties have of complying with
these conditions.
I need hardly remind you that, owing to the lateness of the season,
you will require that the vessel should be prepared to run her
first voyage almost immediately after the engines are fixed. You
will remember, also, that it will be the longest voyage yet run;
that in the event of unfavourable weather a total failure might be
the result of the engine not working to its full power, or
consuming too great a quantity of coals--a very common occurrence
with engines apparently well made, after six or eight days’
constant work; and, lastly, that the future success of the boat as
a passenger ship--nay, even of the company’s boats generally, and,
to a great extent, and for some time, the reputation of Bristol as
an American steamboat station, may depend upon the success of this
first voyage. It is indispensable, therefore, to secure as far as
possible a machine which shall be perfect in all its details from
the moment of its completion. There may be time for a few trials
for ascertaining the fact of its completion, but there will be none
for effecting any alterations should they be found necessary, or
for making any experiments. The machinery which you require to be
so perfect is by no means an ordinary steam-engine.
Marine engines of 80 or 90, and even some of 100 horse-power, are
mere models on a large scale of the ordinary-sized engines. Engines
of 160 or 180 horse-power each would be unmanageable without many
material modifications in the details; the arrangement must be
different, and, as the strength of materials remains the same, the
proportionate dimensions of the parts must be modified. Many
contrivances of this description have been introduced into the
large engines of 110 horse-power each made for the Navy. From 110
to 160 is still another and a very great stride. Those who have led
the way in the first step are certainly the most likely to be aware
of the difficulties of the second, and to be able to appreciate
them better, and be more prepared to overcome them than those who
have as yet only manufactured, however successfully, engines of the
ordinary class. Of three parties tendering.... Messrs. Maudslay
have made by far the largest number, and have for some years led
the way in the introduction of the largest armed steamboats; and
there can be no question as to the fact that they are the oldest
manufacturers of marine engines, that they are themselves the
originators of the greatest number of the improvements of the day,
that they have made the largest engines yet made, and the greatest
number of large engines of all sizes; and, lastly, that they have
the principal supply of engines for the large war ships now used
for the Navy, and have had hitherto the sole supply of all above 70
horse-power. With these facts before you, it remains only for you
to consider how far you agree with me in the conclusion I have come
to, and which I have no hesitation in expressing--that I think you
will be safest, in the peculiar case of the first ship, in the
hands of the parties who have had most experience, and that Messrs.
Maudslay are those persons. Their price is, I think, moderate.
This report was read by Mr. Brunel at a meeting of the Board, summoned
at his request; the Directors adopted his advice, and accepted the offer
of Messrs. Maudslay & Field, of Lambeth.[119]
The ‘Great Western,’ for so the ship was called, had not been long
commenced when a somewhat celebrated controversy arose, in which the
correctness of Mr. Brunel’s views was questioned by the late Dr.
Dionysius Lardner.
The circumstances which led to this discussion were as follows:--
The British Association for the Advancement of Science held its sixth
meeting at Bristol in August 1836; and, as Dr. Lardner was announced to
lecture on Transatlantic Steam Navigation, great interest was felt in
Bristol on the occasion.
After some postponement, he delivered his lecture on August 25, to a
crowded meeting of the Mechanical Section. The proceedings of the
Association unfortunately do not give any report of Dr. Lardner’s
observations; but, as in his latest work on the subject[120] he speaks
in commendatory terms of the report given in the ‘Times’ newspaper, that
account may be relied on as correct.
In the ‘Times’ of August 27, 1836, it is stated that in the course of
his lecture Dr. Lardner said,--
Let them take a vessel of 1,600 tons, provided with 400 horse-power
engines. They must take 2⅓ tons for each horse-power, the vessel
must have 1,348 tons of coal, and to that add 400 tons, and the
vessel must carry a burden of 1,748 tons. He thought it would be a
waste of time, under all the circumstances, to say much more to
convince them of the inexpediency of attempting a direct voyage to
New York, for in this case 2,080 miles was the longest run a
steamer could encounter: at the end of that distance she would
require a relay of coals.
There is no detailed report remaining of the animated discussion which
followed the lecture, and in which Mr. Brunel took part. He exposed
several errors in Dr. Lardner’s calculations, but failed to produce any
effect upon the majority of those present, who were powerfully impressed
by the lecturer’s dogmatic assertions.
Those assertions seem to have had a wide circulation beyond the walls of
the lecture-room; and if Dr. Lardner’s arguments were sound, and if
transatlantic steamers ought to have taken their departure from ‘the
most western shore of the British Isles,’ the enthusiastic advocate of a
railway scheme in Ireland might well exclaim,--
The promoters of this vast object stand forewarned of defeat. Dr.
Lardner, who has bestowed a great deal of pains in arguing the
bearings of this undertaking, has pronounced it impracticable; and
I entirely agree with him in his conclusions. The effort,
nevertheless, will be made; the genius of English enterprise will
hazard the consequences; and every honest spirit that shall hear of
the brave British crew which will embark upon that perilous
expedition will feel his heart beating high for the
merchant-sailor, whom nothing can deter. He will sail; but, though
dangers will encompass him, and destruction appear, there is yet a
hope for his ultimate success. Let us cheer ourselves with the
expectation that, as the exhausted mariner returns, he will fall in
with the western shores of Ireland; that, worn out and hopeless of
home and comfort upon earth, the Shannon will win him to her bosom;
that, invited by the graceful sinuosities of that noble stream, and
the rich and fertile lands around, he will advance to this
convenient and improving city; and as he rests within its walls
that he will exclaim, ‘This is the place from which I ought to have
set out, for here have I returned with ease and safety!’[121]
Dr. Lardner’s views are repeated in an article in the ‘Edinburgh Review’
for April 1837 (vol. lxv.); and in the report of the proceedings of the
British Association for 1836 (p. 130 of the proceedings of the
sections), the reader is referred to this article, apparently as a
substitute for an abstract of the lecture.
The following _résumé_ is there given of the lecture:--
The conclusions at which he arrived were briefly these: that, in
the present state of the steam-engine as applied to nautical
purposes, he regarded a permanent and profitable communication
between Great Britain and New York by steam-vessels making the
voyage _in one trip_ as in a high degree improbable; that since the
length of the voyage exceeds the present limits of steam-power, it
would be advisable to resolve it into the shortest practicable
stages; and that, therefore, the most eligible point of departure
would be the most western shores of the British Isles, and the
first point of arrival the most eastern available parts of the
western continent; and that, under such circumstances, the length
of the trip, though it would come fully up to the present limit of
this application of steam-power, would, nevertheless, not exceed
it, and that we might reasonably look for such a degree of
improvement in the efficiency of marine engines as would render
such an enterprise permanent and profitable. (P. 119.)
Among other objections to long voyages the reviewer enumerates the
incrustation of boilers, and the choking of smoke flues; and then, with
reference to the quantity of fuel required, he proceeds:--
In proportion as the capacity of the vessel is increased, in the
same ratio or nearly so must the mechanical power of the engines be
enlarged, and the consumption of fuel augmented.... It is therefore
demonstrable that, in the present state of steam navigation, if
this voyage shall be accomplished in one uninterrupted trip, the
vessel which performs it must, whatever may be her power and
tonnage, be capable of extracting from coals a greater mechanical
virtue, in the proportion of three to two, than can be obtained
from them by the combined nautical and mechanical skill of Mr.
Lang, the builder of the ‘Medea,’ and Messrs. Maudslay and
Field.... That the passage from Liverpool to New York cannot on any
occasion be made in one run by a steam-ship we do not maintain....
The average time of the outward voyage to New York is thirty-six
days, and we say that when the circumstances of wind and water are
such that a sailing vessel would require that time to make the
passage, a steamer cannot make it without an intermediate supply of
fuel. (Pp. 127, 139, 143.)
To sum up Dr. Lardner’s views in his own words written at about this
time,[122] ‘We have as an extreme limit of a steamer’s practicable
voyage, without receiving a relay of coals, a run of about 2,000
miles.’[123]
It will be seen from these extracts that the proposition Dr. Lardner
laid down as the basis of his ‘demonstration’ was, that the power of the
engines must be increased as the size of the vessel. Were this true his
conclusion would also be true--namely, that the capacity of a given
vessel regularly to accomplish a given voyage does not increase with the
increase of size, since the consumption of fuel is augmented in about
the same ratio.
This assumption is directly opposed to the opinion held by Mr. Brunel,
and acted on by him in his recommendations to the Steam-Ship
Company--namely, that while the tonnage of a ship is increased as the
cube of her dimensions, the resistance is increased only about as the
square.
This question was the main point at issue between Dr. Lardner and Mr.
Brunel; and the proposition which Mr. Brunel then asserted is at the
present time the basis of the calculations which determine the
proportion between the tonnage of a steam-ship and the length of voyage
she has to perform without a relay of fuel.
* * * * *
The history of the ‘Great Western’ steam-ship has been interrupted by
this examination of Dr. Lardner’s propositions. The weight at one time
attached to his opinions, the sinister influence they exercised over the
early efforts of those who differed from him, and the great and enduring
importance of the points at issue, have made it necessary to refer to
them at length.
The ship had been steadily proceeded with, notwithstanding the adverse
criticism of philosophers, and she was launched on July 19, 1837. On
August 18 she left with a tug-boat for London to take her engines on
board, and arrived in the Thames after a passage of four days,
four-fifths of the way under sail.
When anchored in the river she was crowded with visitors, who, according
to the newspapers of the day, were astonished at ‘her magnificent
proportions and stupendous machinery.’
The engines were at length completed, and received in every detail Mr.
Brunel’s constant supervision.
Extraordinary efforts were made to get the ship back to Bristol and to
start her on her voyage across the Atlantic before the departure of the
‘Sirius’--a vessel of about 700 tons and 320 horse-power, bought by the
St. George’s Steam Packet Company in order to anticipate the ‘Great
Western.’
At length the ‘Great Western’ left Blackwall for Bristol, at 6.10 A.M.
on Saturday, March 31, 1838, having on board Captain Claxton, Mr. Guppy,
Mr. Brunel, and many other persons interested in her success. All went
well at first, but at about half-past eight o’clock a very alarming fire
broke out. The felt which covered the boilers had been carried up too
high, and the red lead which fastened it became hot; oil gas was
generated, and it burst into a fearful flame, setting fire to the beams
and under part of the deck. The ship was immediately run ashore on a
mud-bank not far from the Chapman Beacon, while Captain Claxton, Captain
Hosken (the commander), and Mr. Pearne (the chief engineer) endeavoured
to extinguish the fire.
Captain Claxton went below through the engine-rooms, and forward between
the boilers to the fore-hatch, and in a stifling atmosphere of burning
paint and felt he directed the nozzle of the fire-hose against the
flames. While he was at work, something heavy fell on him from above. On
recovering from the blow, he stooped down, and found the body of a man,
who was lying insensible, with his head covered to the ears with the
water which had collected on the floor. Captain Claxton called for a
rope, and the almost lifeless body was hauled up. It was not till he
went on deck some time afterwards that he learnt that the person who had
fallen on him was Mr. Brunel, and that he had saved the life of his
friend.
It appeared that Mr. Brunel was going down to Captain Claxton’s
assistance by the long ladder which reached from the fore-hatch to the
keelson, and put his foot on a burnt rung. He fell about 18 feet,
striking an iron bar in his descent. Had he not fallen on Captain
Claxton he must have struck the keelson or floor and been killed, and
had not his head been raised at once he would have been suffocated by
the water into which he fell. He was so severely hurt that he could not
move, and he was laid on a sail on deck until the fire was extinguished,
and then lowered into a boat, and landed on Canvy Island, where he
remained some weeks. Although his sufferings were very great, he was
able, within three days of the accident, to dictate a long letter to
Captain Claxton on the state of the ship and engines.
The fire was soon got under, the ship resumed her voyage to Bristol, and
anchored at Kingroad in the afternoon of Monday, April 2, to the great
surprise of the good people of Bristol, who had heard that she had been
burnt in the Thames. Their astonishment was increased by finding no
outward signs of the disaster; but, as a fact, the deck above the boiler
was charred a fourth of its thickness, and so remained till the ship was
broken up.
The ‘Great Western’ started on her first voyage to New York on Sunday,
April 8, at 10 A.M.,[124] and struck soundings off Newfoundland on the
ninth day. She arrived at New York at 2 P.M. on Monday, the 23rd, having
consumed three-fourths of the coal she had taken on board.
She found that the ‘Sirius’ had arrived before her; but under all the
circumstances the palm was due to the ‘Great Western,’ for the ‘Sirius’
had left Cork eight hours before the ‘Great Western’ left Bristol (which
lies a whole day’s run further from New York), and had only arrived at
New York in the morning of the day in the afternoon of which the ‘Great
Western’ came in; and, what is after all the most important point for
comparison, the ‘Great Western’ had nearly 200 tons of coal left, while
the ‘Sirius,’ when she dropped her anchor at Sandy Hook, had not only
consumed all her coal, but also all the combustible articles which
could possibly be thrown on the fire, including (to repeat the
well-known anecdote) a child’s doll!
The ‘Great Western’ was received at New York with well-deserved honour.
According to the journal of one of her passengers, ‘Myriads were
collected, boats had gathered round us in countless confusion, flags
were flying, guns were firing, and cheering rose from the shore, the
boats, and all around loudly and gloriously, as though it would never
have done. It was an exciting moment, a moment of triumph.’
The ship started on her return home on May 7, 1838, with sixty-eight
passengers on board. She made the voyage in fourteen days, although
twenty-four hours were lost by a stoppage at sea.
After this she ran regularly between Bristol and New York till the end
of 1846. In April 1847 she was sold to the West India Mail Steam Packet
Company, and became one of their best vessels.
* * * * *
At length in 1857 she was broken up by Messrs. Castle, of Vauxhall.
Among those who went there to take a farewell of her before she finally
disappeared was Mr. Brunel; thus he saw the last of his famous ship.
NOTE (p. 235).
_Dimensions of the ‘Great Western’ Steam-Ship._
Feet Inch
Length from fore-part of figurehead to after-part
of taffrail 236 0
Length between the perpendiculars 212 0
Length of keel 205 0
Breadth 35 4
Breadth over paddle-boxes 59 8
Depth of hold 23 2
Draught of water 16 8
Length of engine-room 72 0
Tonnage by measurement 1,340 tons
Displacement at load draught 2,300 "
_Dimensions of Engines, &c._
Diameter of cylinders 73½ inches
Length of stroke 7 feet
Weight of engines, wheels, &c. 310 tons
Weight of boilers 90 "
Water 20 tons to each boiler 80 "
Diameter of wheel 28 feet 9 inches
Width of floats 10 feet
CHAPTER IX.
_STEAM NAVIGATION. THE ‘GREAT BRITAIN’ STEAM-SHIP._
A.D. 1838--1847. ÆTATIS 33--42.
COMMENCEMENT OF THE BUILDING OF THE ‘GREAT BRITAIN’--REPORT ON THE
ENGINES (JUNE 13, 1839)--EXPERIMENTS ON THE SCREW PROPELLER--ITS
ADOPTION IN THE ‘GREAT BRITAIN’--COMPLETION OF THE SHIP--HER VOYAGE
ACROSS THE ATLANTIC--STRANDING OF THE ‘GREAT BRITAIN’ IN DUNDRUM
BAY--LETTER TO CAPTAIN CLAXTON ON THE CONDITION OF THE ‘GREAT
BRITAIN,’ AND ON THE MEANS TO BE ADOPTED FOR SAVING HER (DECEMBER
10, 1846)--REPORT TO THE DIRECTORS ON THE SAME SUBJECT (DECEMBER
14, 1846)--APPOINTMENT OF CAPTAIN CLAXTON TO SUPERINTEND THE
EXECUTION OF MR. BRUNEL’S PLANS--LETTER TO CAPTAIN CLAXTON ON THE
DIFFICULTIES TO BE OVERCOME (DECEMBER 29, 1846)--REPORT ENCLOSING
CAPTAIN CLAXTON’S ACCOUNT OF THE ERECTION OF THE BREAKWATER
(FEBRUARY 27, 1847)--REPORT ON THE ARRANGEMENTS FOR FLOATING OFF
THE SHIP (MAY 4, 1847)--SUCCESSFUL ACCOMPLISHMENT OF THE FLOATING
OPERATIONS--SUBSEQUENT HISTORY OF THE ‘GREAT BRITAIN’--_NOTE_:
DIMENSIONS OF THE SHIP AND ENGINES.
The Directors of the Great Western Steam-Ship Company, encouraged by the
success of the ‘Great Western,’ determined shortly after her first
return to England to lay down a second ship of not less than 2,000 tons
burden. As they did not at that time contemplate the use of iron, a
portion of the timber was purchased, and drawings were put in hand for a
wooden ship. The proposed vessel was intended to be in all respects a
companion ship to the ‘Great Western;’ only she was to be of larger
dimensions, as it was found that additional cargo space would be
remunerative.
In October 1838, Mr. Guppy (one of the Directors) communicated to the
Board the results of some calculations Mr. Brunel had made relative to
the cost and efficiency of iron vessels as compared with wooden ones.
Mr. Brunel then suggested that Captain Claxton and Mr. Patterson,
accompanied by one of his assistants, should make a voyage to Antwerp
and back in the ‘Rainbow,’ an iron steam-boat of 407 tons burden, and
report on the subject. On receiving their report, which was revised by
Mr. Brunel, and which was strongly in favour of the adoption of iron,
the Directors resolved to build their ship of that material, and of not
less than 2,000 tons measurement, the same size as that which they had
intended for their wooden ship. They also determined to erect the shops,
and provide the tools for building her themselves.
As in the case of the ‘Great Western,’ the details of construction were
settled by the Building Committee--Captain Claxton, Mr. Guppy, and Mr.
Brunel--who were assisted by Mr. Patterson.
The preparation of the design occupied some time. In each succeeding
drawing an increased size was proposed; at length the fifth design,
showing a ship of 3,443 tons burden, was finally approved of. On July
19, 1839, the flat keel plates were laid, and the construction of the
hull was commenced.
It will be necessary to enter with some detail into the history of the
construction of the engines of the ‘Great Britain,’ as it has often been
stated that it was on Mr. Brunel’s recommendation that the Company built
their own engines. It appears, however, that Mr. Brunel repeatedly urged
upon the Directors the utmost caution and economy, and that they
ultimately acted ‘against his suggestion.’
When the Directors determined, in May 1838, to build a second ship,
they did not entertain any idea of undertaking so great a responsibility
as the manufacture of the engines; nor had they any intention of doing
so, even when, towards the end of the same year, they resolved to build
the ship themselves, and to construct her of iron.
The dimensions of the proposed paddle engines (for at this date the use
of the screw propeller was not contemplated) were sent, in November
1838, to Messrs. Maudslay and Field, Messrs. Hall, and Messrs.
Seaward.[125]
Messrs. Maudslay declined to tender, and the negotiations seem to have
fallen through at the time; but they were renewed in April 1839, when
estimates for engines (with cylinders of 100 inches diameter and seven
feet stroke) were again invited from several makers.
The contest lay eventually between Messrs. Maudslay and Mr. Humphrys
(whose patent for trunk engines was worked by Messrs. Hall). At Mr.
Brunel’s desire they prepared designs for engines with cylinders of 120
inches diameter. He twice induced the Directors to postpone coming to a
decision on the subject, in order that Messrs. Maudslay might mature
their new patent for double-cylinder engines.
When their tender was placed before the Board, the Directors were of
opinion that it largely exceeded the estimate of Mr. Humphrys. Mr.
Humphrys’ estimate, however, had been more than once sent back to him
for revision, at the suggestion of Mr. Brunel, who expressed doubts as
to the possibility of Mr. Humphrys being able to construct his engines
within the sum named by him.
Messrs. Hall stated that if they tendered for the supply of engines on
Mr. Humphrys’ plan, large tools would have to be purchased by them, and
the cost charged on the one pair of engines; they therefore strongly
recommended the Company to become their own engine makers.
Influenced by these considerations, the Directors determined to adopt
the plan of Mr. Humphrys, and to construct their own engines; and they
appointed him the superintending engineer of their works.
It appears from a report by the secretary, Captain Claxton, dated March
23, 1840, that ‘previous to coming to this decision, Mr. Brunel
succinctly laid before the Directors his views of the matter, and his
opinion of the great responsibility they would incur if they made their
own engines; and doubtless the Directors would have yielded to his
suggestions, but for the report of Mr. Humphrys, showing the utter
hopelessness of getting the engines made piecemeal in Bristol.’
The following is the report of Mr. Brunel on the subject:--
June 12, 1839.
At the request of Mr. Maze and Mr. Scott, whom I had the pleasure
of meeting on Saturday last, I send you the following observations
on the two plans and the estimates of Messrs. Maudslay, and of our
Mr. Humphrys.
I have a copy of Messrs. Maudslay’s letter of the 29th ult.
containing their tender, and a subsequent letter of the 11th inst.
in reply to some enquiries of mine respecting their tender and Mr.
Humphrys’ estimates, according to which the total cost of a pair of
engines of 110 inches diameter and 8 feet stroke, upon his plan,
and I presume modified as last recommended by Mr. Guppy and myself,
including boilers and fixing on board, would be 29,296_l._, or, as
stated by Captain Claxton in a letter to me of the 1st inst.,
30,700_l._
First, as to the comparative merits of the plans, I consider them
both excellently adapted to our particular case, and that the
choice will depend upon other circumstances than the construction
of the engines, and these circumstances, I consider, would be, the
relative cost and the advantages of forming an establishment which
will eventually become necessary for the repair and maintenance of
our engines, contrasted with all the advantages to be derived from
the responsibility and experience in all the details of a
first-rate manufacturer, and to which I attach very great value,
particularly in the early proceedings of a Company like ours. As
regards the cost, I understand Messrs. Maudslay’s tender to be for
an engine of four 75-inch cylinders, which is equal to a pair of
ordinary engines of about 106 inches.
Engine, boiler, and paddle-wheels, fixed on board, supposing the £
vessel in London, and with reduced size of boiler, 41,400
Deduct allowance for coal-boxes and combings for hatchways as proposed
by Messrs. Maudslay, 500
40,900
Additional expense incurred by Messrs. Maudslay in consequence of
the engines being fixed on board at Bristol instead of London, I
estimate at, 250
Total amount to be paid Messrs. Maudslay, 41,150
In addition to this will be the freight and insurance, which we are to
pay, and also the unloading at Bristol and placing in the vessel,
which I take at Captain Claxton’s estimate, 2,000
Making a total of 43,150
It is to be observed that this includes Mr. Field’s apparatus for
changing water, Kingston’s cocks, casing the cylinders, and all
those extras which were applied to the ‘Great Western,’ and also
the paddle-beams and paddle-wheels. Without these latter the nett
cost of the engine, fixed in place, and including all other extras,
would appear to be about 40,000_l._ or 40,500_l._ If the cylinders
be increased to 77¾, which would be equivalent to the pair of 110
inch, and supposing the cost of the engines to increase in the same
ratio as the power resulting from this increase, but which ought
not to be the case, the total cost, according to Messrs. Maudslay’s
estimate, will be 46,500_l._, and deducting the paddle-beams or
framework for carrying the paddles, which do not, I think, form
part of Mr. Humphrys’ estimate, probably about 45,500_l._ as
compared with Mr. Humphrys’ estimate of 30,700_l._ With respect to
this latter estimate, I cannot help expressing the fears I
entertain that Mr. Humphrys is over-sanguine, and that the cost
would greatly exceed the sum named. The items seem to me to be
moderate prices only for each article named, and I see no allowance
for those alterations, damages, and waste of parts, and a variety
of other contingencies, which in a piece of machinery of this
magnitude and novelty is certain to amount to a very large sum.
In his estimate of the fittings and smaller parts, I think also he
has greatly underrated them.
The outlay for tools and tackle would, I think, also be greater
than he seems to anticipate, and on the whole I cannot but come to
the conclusion in my own mind, and I should not act rightly if I
did not communicate that opinion to you, that the first outlay will
be fully as large and probably larger by adopting the plan of
making our own engines than by employing a manufacturer. It is true
we shall have some valuable and costly tools and shops included in
this outlay, and a fine establishment formed, which may be rendered
fully competent in point of means to continue the manufacture of
engines for others, and to keep up the repairs of any number of
engines which the Company are likely to have at work. My only fear
would be that of the risk of the undertaking being too great for a
newly-formed establishment. The making of the vessel itself is no
mean effort, and to superadd the construction of the largest pair
of engines and boilers yet made, and upon a new plan, is
calculating very much upon every effort being successful, and
particularly upon the continued assistance of those who have
hitherto attended to the subject; as it must be well known to the
Directors that if Mr. Guppy, for instance, should be prevented from
giving his time as he has hitherto done, or if Mr. Humphrys should,
from illness or other causes, leave us, the manufactory would be
brought to a stand, and the loss would be serious. I have no wish
to deter the Company from becoming their own manufacturers--I think
it a course which must ultimately be adopted if the Company
thrive--but I should have much preferred that it had been adopted
gradually, that we had commenced with a vessel, and then proceeded
with boilers and repairs; and, as our establishment became formed
and matured, and when we might no longer depend entirely upon the
engineering talents and assistance of one Director, who may be
unable to attend to it, or upon the health of one superintendent
who, as yet, is alone in possession of all our plans and ideas, and
at present is alone capable of carrying them out, we might then
have ventured upon making the engines perhaps for the third vessel.
Circumstances may, however, render it necessary that we should
proceed more expeditiously, and I am only anxious that the
Directors should be aware of the difficulties that we may have to
encounter, and that they should not form expectations as regards
economy in which they may be disappointed. The result of the best
consideration I have been able to give to it is, that the question
does not seem to be one of cost. In that respect, according to my
view, the two modes of proceeding would be nearly balanced, but it
resolves itself into the following question:--Is it better in our
present position to enter at once upon the manufacture of the
engines and boilers, in doing which we shall in part repay the cost
of tools and shops, which must eventually be required, and by which
we shall be more independent, and more capable of expediting the
works, should it become desirable to incur any additional expense
for that purpose, or to throw all the responsibility and risk on
another party or contractor--the vessel, for which we could not
easily contract, being still made in the Company’s yard?
I have thus reduced the question to that state in which I can offer
no further opinion or advice; it is now for you to determine. The
question is one which has frequently to be decided upon by the
Directors of public works; it is very much a matter of feeling, but
it is simplified in the present instance by the circumstance that
the expense in either case will be, to my view at least, about the
same, and the work, I have no doubt, equally good in either case.
Upon this point, as perhaps upon the subject of cost, I have no
doubt there will be some difference of opinion. It will be said
that the work done under our own superintendence can be more relied
upon than the work of a manufacturer, and that even in the engines
of the ‘Great Western’ steam-ship, coming from one of the most
experienced manufacturers, many defects may be pointed out.
I should agree fully with both these arguments, but I think these
advantages are fully counterbalanced by that of the experience in
all the details which is brought into operation in an
old-established manufactory, and the great relief from
responsibility and risk obtained by contracting for the whole work.
The Directors having determined to make the engines, erected shops and
fitted them up with proper tools. The services rendered to them by Mr.
Brunel at this period were fully acknowledged at the next meeting of the
shareholders.[126]
Mr. Brunel’s attention was now anxiously devoted to the consideration of
the numerous questions involved in the construction of the ship and her
engines; and, in order to obtain reliable information on many points, he
sent one of his assistants, Mr. Berkeley Claxton, in the ‘Great
Western.’ His sole occupation during six voyages was to note the amount
of rolling and pitching, and the exact performance of her engines, with
the effect of the use of the expansion valves on her speed, and on the
consumption of fuel. These reports furnished Mr. Brunel with information
which was of great value, especially when, shortly afterwards, he
advised the Directors to adopt the screw propeller instead of
paddlewheels.
The circumstances which led to the adoption of the screw propeller in
the ‘Great Britain’ instead of paddlewheels were as follows:--
In the early part of the year 1840, the performances of the ‘Archimedes’
steamer began to attract the attention of scientific men. This vessel,
which was fitted with the screw propeller patented by Mr. Francis
Pettitt Smith, arrived at Bristol in May. A few trips were made up and
down the Float, but the advantages of the screw propeller were not fully
appreciated by those to whom they were explained.
But Mr. Guppy, who had attended some of these trials, went round in the
ship to Liverpool. On his return he made a report to the Building
Committee, and the Directors, on Mr. Brunel’s advice, passed a
resolution delaying the progress of the engines of the ‘Great Britain,’
and of those parts of the frame which would be affected by any change of
plans. Mr. Brunel was also requested by them to give his attention to
the question of the adoption of the screw, and to report thereon.
During the next three months experiments were made by Mr. Brunel,
assisted by Mr. Guppy and Captain Claxton, on the screw propeller in the
‘Archimedes.’[127] These experiments afforded ample opportunity of
trying the performances of several forms of screws.[128]
On October 1, Mr. Brunel attended a special meeting of the Board, and
read and explained a report he had drawn up, in which he laid before the
Directors at great length the results of the different experiments he
had made, and the advantages which he believed would attend the use of
the screw propeller.[129] A resolution was passed adopting it for the
‘Great Britain.’
Mr. Brunel at first thought that he would be able to retain the form of
engines which had been originally determined on for working the paddle
wheels; but, on consideration, this was found impracticable. As the
Company had by this time erected complete engine works, there could now
be no question as to their undertaking the construction of the new
description of engines required for working the screw propeller.[130]
Mr. Humphrys resigned the post of superintendent of the works, and Mr.
Harman was appointed assistant engineer under Mr. Guppy, to whom the
Directors, on the advice of Mr. Brunel, entrusted the supreme control of
their manufacturing establishment.
The duties and responsibilities which devolved on the Building
Committee--Captain Claxton, Mr. Guppy, and Mr. Brunel--were most
arduous. To design and construct a steam-ship larger than any that had,
up to that time, been launched, to make this ship of a material which
had but lately been introduced into shipbuilding, and which had never
before been employed on a large scale, to adapt to this ship a novel
form of propeller which had not previously been used save in a merely
experimental steamer, and to build in a newly opened manufactory marine
engines of a much greater size than any that had hitherto been
contemplated, and of a totally different character, was indeed a bold
enterprise. Mr. Brunel had, as has been shown, recommended the Company
not to undertake one part of the work, that, namely, of the manufacture
of the engines, which he thought would have been better entrusted to the
most experienced engine builders. But although the Directors had acted
contrary to his advice, this circumstance in no way diminished the zeal
with which he and his coadjutors entered upon their task.
A short statement of the principal dimensions of the vessel and engines
is given in a note to this chapter; but some of the more remarkable
features in the design may be mentioned here.
In the construction of the ‘Great Britain,’ the same care which had been
spent in securing longitudinal strength in the wooden hull of the ‘Great
Western,’ was now given to the suitable distribution of the metal. Over
the transverse angle iron ribs at the bottom of the ship were laid ten
deep longitudinal beams (see woodcut, fig. 13, _a_), which, over the
greater part of the bottom of the ship, were covered with an iron deck
(_b_) riveted to their upper edges by angle irons, thus forming a
cellular structure which added greatly to the strength of the ship. It
does not appear that this deck was designed to be watertight, so that it
did not form the same security against accident as the inner skin of
the cellular structure which Mr. Brunel afterwards adopted in the ‘Great
Eastern.’
The upper part of the sides of the ship, in the middle of her length,
were carefully designed so as to give her longitudinal strength. The
side plates were thickened, and were riveted to iron shelf-plates three
feet broad (_c_); and two bands of iron, six inches wide and one inch
thick, with the joints strengthened, ran along the top of the ship’s
side. There were bands of iron riveted to the shelf-plate, and iron deck
beams crossed diagonally under the planking of the upper and main decks.
Also at the junction of the ship’s side with the shelf-plate there ran
longitudinally a tie of Baltic pine timber, 340 square inches in section
(_d_); this being well secured to the shelf-plate and ribs, added
considerably to the strength of this portion of the hull.
The ship had five watertight bulkheads, and was thus separated into six
compartments.
[Illustration: _Scale of feet_.
Fig. 13. ‘Great Britain’ Steam-Ship.
_Transverse Section._]
She had no keel, as there did not appear to be sufficient advantage
gained by such an appendage to make up for the increase of the ship’s
draught by the amount of the depth of the keel. There were two side or
bilge keels (_e_), reaching down to the level of the keel plate of the
ship, so that when grounded in dock she might rest on three points in
her width.
The ‘Great Britain’ had what is termed a balanced rudder, a portion of
the rudder (in this case about one third) being in advance of the pivot
on which it turned. The result of this arrangement was that, the
pressures on either side of the pivot nearly balancing one another,
there was no difficulty in putting the helm over rapidly. This rudder
was knocked away when the ship ran ashore at Dundrum, and was
subsequently replaced by an ordinary rudder.[131]
In the construction of the hull of the ship, instead of a mere imitation
of the arrangements of the timber in wooden ships, the proper
distribution of the material to receive the strains that would come upon
it was carefully considered. In the result, the ship contained, in the
structure of her bottom, bulkheads, deck shelves, and longitudinal
kelsons, the longitudinal principle of construction which Mr. Brunel
afterwards so fully developed in the ‘Great Eastern.’
Apart from their size, the design of the engines of the ‘Great Britain’
necessarily presented many peculiarities. The boilers, which were six in
number, were placed touching each other, so as to form one large boiler
about thirty-three feet square, divided by one transverse and two
longitudinal partitions. This boiler, which was fitted in between the
longitudinal bulkheads of the ship, had a double set of furnaces, and
therefore of stoke-holes, one at the fore end, and the other at the
after end, next the engine room.
It would seem that the boiler was only worked with a pressure of about
eight pounds on the square inch.
The feed water for the boiler was passed through a casing surrounding
the funnel, in which it was heated before passing into the boiler. This
casing was open at the top, and the water flowed thence into the boiler
by gravitation. A similar arrangement was adopted by Mr. Brunel in the
‘Great Eastern.’
The condensers were made of wrought iron, being in fact part of the
frame of the ship. The main shaft of the engine had a crank at either
end of it, and was made hollow, a stream of water being kept running
through it so as to prevent heating in the bearings. An important point
in the design was the method by which the motion was transmitted from
the engine-shaft to the screw-shaft, for the screw was arranged to go
three revolutions to each revolution of the engines. Where the engines
do not drive the screw directly, this is now universally effected by
means of toothed gearing; but, when the engines of the ‘Great Britain’
were made, it was thought that this arrangement would be too jarring and
noisy. After much consideration, chains were used, working round
different-sized drums with notches in them, into which fitted
projections on the chains. The greater part of the length of the
screw-shaft consisted of a hollow wrought-iron boiler-plate tube, the
metal being thus very advantageously placed for taking torsional strain,
and the shaft was in this way made very light. The engines were designed
to work expansively, the steam being cut off at one-sixth of the stroke.
The completion of the ‘Great Britain’ was delayed many months, owing to
the financial difficulties in which the Great Western Steam-Ship
Company had become involved; the profit on working the ‘Great Western’
having been seriously diminished in consequence of the competition of
the Cunard steamers.
At length, however, the ship was finished; and she was floated out of
dock into the Floating Harbour on July 19, 1843, in the presence of His
Royal Highness Prince Albert.
This seems a fitting place to insert the following letter from Mr.
Brunel to Mr. Guppy, written at the beginning of August 1843:--
I have been thinking a great deal of your plans for iron-ship
building, and have come to a conclusion which I believe agrees with
your ideas; but I will state mine without reference to yours. At
bottom and at top I would give _longitudinal_ strength and
stiffness, gaining the latter by the former, so that all the metal
used should add to the _longitudinal tie_, while in the neutral
axis and along the sides, and to resist swells from seas, I would
have vertical strength by ribs and shelf-pieces, thus: the black
lines being sections of longitudinal pieces, the dotted lines
vertical and transverse diagonal plates, throwing the metal as much
as possible into the outside bottom plates, and getting the
strength inside by form, that is, depth of beams, &c., the former
being liable to injury from blows, &c., the latter being protected.
[Illustration: [Fig. 14.]]
And now for the screw of which I am constantly thinking, and in the
success of which for the ‘Great Britain,’ remember, I am even more
deeply interested than you.
If all goes well we shall all gain credit, but ‘_quod scriptum est
manet_,’ if the result disappoint anybody, my written report will
be remembered by everybody, and I shall have to bear the storm--and
all that spite and revenge can do at the Admiralty will be done!
The words ‘better sailing qualities than could be given to the
“Polyphemus,”’ which I used in my first report to the Admiralty, I
believe have never been forgotten.
Well, the result of all my anxious thoughts--for I assure you I
feel more anxious about this than about most things I have had to
do with--is first that we must adopt as _a principle not to be
departed from_, that all mechanical difficulties of construction
must give way, must in fact be lost sight of in determining the
most perfect form--if we find that the screw determined upon
_cannot_ be made (but what cannot be done?), then it is quite time
enough to try another form; though even then _my_ rule would be to
try _again_ at making it....
The ‘Great Britain’ was built wider than the locks through which she
would have to pass, as it was supposed that the Dock Company would allow
them to be temporarily widened.[132]
After a good deal of discussion, negotiations were satisfactorily
concluded, and the requisite alterations were made: the ship passed
through into Cumberland Basin, and the upper lock was restored to its
original state in a few days.
On December 10, everything was ready for her passing into the Avon
through the lower lock. A steam-tug commenced towing her at high water,
but, before she had moved half her length in the lock, it became evident
to Captain Claxton, who was on board the tug, that there was not an inch
to spare; she was touching the lock walls on either side--in fact, she
had stuck between the copings. Upon this he gave orders to haul her back
again as quickly as possible. This was hardly effected before the tide
began to fall; a few minutes later, and the ship would have remained
jammed in the entrance.
As the tides had passed their highest, it was necessary immediately to
widen the lock, in order not to lose the spring tide; and this was
accomplished under Mr. Brunel’s superintendence, just in time to get the
vessel through that night.
Mr. Brunel described this occurrence in the following letter, written to
excuse himself from keeping an important engagement in Wales:--
December 11, 1844.
We have had an unexpected difficulty with the ‘Great Britain’ this
morning. She stuck in the lock; we _did_ get her back. I have been
hard at work all day altering the masonry of the lock. To night,
our last tide, we have succeeded in getting her through; but, being
dark, we have been obliged to ground her outside, and I confess I
cannot leave her till I see her afloat again, and all clear of her
difficulties. I have, as you will admit, much at stake here, and I
am too anxious about it to leave her.
The ‘Great Britain,’ after making several experimental trips, sailed for
London on January 23, 1845, and, although she experienced very severe
weather, made an average speed of 12⅓ knots an hour.
The excitement caused by her arrival at Blackwall was very great.
Thousands of persons flocked to see her, and she was honoured by a visit
from Her Majesty and His Royal Highness Prince Albert.
She left Liverpool on her first voyage on August 26, and arrived at New
York on September 10, having made the passage out in fourteen days and
twenty-one hours. She made her return passage in fifteen days and a
half.
She started again in October, taking sixteen days and a half across. On
her homeward passage, she broke her screw, and got home under canvas
after eighteen days of rough weather which fully tested her sailing
qualities.
The experience of these voyages showed that the supply of steam from the
boilers was defective; the necessary alterations were carried out
during the winter months, and the ship was fitted with a new screw.
In the beginning of 1846, everything seemed to promise well for the
success of the ‘Great Britain.’ She started on May 9, with her full
complement of passengers and cargo, but again an accident happened,
which prevented this passage from affording a trial of her steaming
power. On May 13, the guard of the after air-pump broke; but up to that
time her speed had averaged eleven and three-quarters knots.
She returned from New York in thirteen days and six hours, against
adverse winds for ten days, with a speed varying from eight and a half
to twelve knots. On one day of her voyage, June 13, she ran 330 knots in
the twenty-four hours, or nearly sixteen statute miles an hour. This was
said to have been the quickest passage which had, up to that time, been
made under similar circumstances of wind and weather.
She left Liverpool again at the beginning of July, and arrived at New
York in thirteen days and eight hours, or, deducting stoppages, in
twelve days and eleven hours--the shortest passage then and for some
time afterwards recorded. Her homeward passage was accomplished in
thirteen days, including a stoppage of eighteen hours to repair the
driving chains which had been damaged.
She started again from Liverpool on her outward voyage on the morning of
September 22, 1846, having on board 180 passengers (a larger number than
had ever before started to cross the Atlantic in a steamer), and a
considerable quantity of freight. A few hours after her departure, and
at a time when it was supposed that she was rounding the Isle of Man,
the ship ran ashore, and all immediate efforts to get her off were
unavailing. When daylight came, the captain found, to his surprise,
that she was in Dundrum Bay, on the north-east coast of Ireland. The
passengers were landed safely when the tide ebbed.
Captain Claxton, the managing Director of the Company, went at once to
the ship. He found her lying at the bottom of a deep and extensive bay;
the ground on which she rested had an upper surface of sand, but
underneath this were numerous detached rocks. The ship had settled down
upon two of them, and had knocked holes in her bottom. Her head lay NW.,
leaving her stern and port quarter exposed to a heavy sea, which, at
Dundrum, always accompanies southerly gales.
When Captain Claxton got to the ship, he made arrangements for trying to
get her off at the next spring tides, which were on the following Monday
(September 28); but on the Sunday, a gale of wind from the southward
sprung up, and at the night flood-tide the water broke over her; nothing
remained to be done but to drive the ship higher up the beach into a
position of greater safety. Sails were therefore set, and she was driven
forward a considerable distance.
Mr. Patterson was sent by the Directors to Dundrum with Mr. Alexander
Bremner (who had had considerable experience in floating stranded
ships), and they endeavoured to protect the vessel by breakwaters.
These, however, were soon carried away; and, after this misfortune, the
Directors seem for a time to have lost all hope of saving their ship.
On December 8, when the immediate pressure of Parliamentary work was
over, Mr. Brunel went to Dundrum, having some time before been requested
by the Directors and underwriters to examine and report on the ship. He
was delighted, he said, in spite of all the discouraging accounts he had
received, to find the ‘Great Britain’ ‘almost as sound as the day she
was launched, and ten times stronger and sounder in character,’ though
at the same time he was grieved to see her ‘lying unprotected, deserted,
and abandoned.’
Whatever may have been the misgivings of others, he felt no doubt as to
the possibility of saving the ship, by at once protecting her by a
breakwater made of fagots; and before he left Dundrum he set Captain
Hosken at work at the new arrangements, and he guaranteed the immediate
expense in the event of the Directors not sanctioning the measure.
Immediately on his return to town, he wrote the following somewhat
vigorous letter to Captain Claxton:--
December 10, 1846.
I have returned from Dundrum with very mixed feelings of
satisfaction and pain, almost amounting to anger, with whom I don’t
know. I was delighted to find our fine ship, in spite of all the
discouraging accounts received, even from you, almost as sound as
the day she was launched, and ten times stronger and sounder in
character. I was grieved to see this fine ship lying unprotected,
deserted and abandoned by all those who ought to know her value,
and ought to have protected her, instead of being humbugged by
schemers and underwriters. Don’t let me be understood as wishing to
read a lecture to our Directors; but the result, whoever is to
blame, is, at least in my opinion, that the finest ship in the
world, in excellent condition, such that 4,000_l._ or 5,000_l._
would repair all the damage done, has been left, and is lying, like
a useless saucepan kicking about on the most exposed shore that you
can imagine, with no more effort or skill applied to protect the
property than the said saucepan would have received on the beach at
Brighton. Does the ship belong to the Company? For protection, if
not for removal, is the Company free to act without the
underwriters? If we are in this position, and if we have ordinary
luck from storms for the next three weeks, I have little or no
anxiety about the ship; but if the Company is not free to act as
they like in protecting her, and in preventing our property being
thrown away by trusting to schemers, then please write off
immediately to Hosken to stop his proceeding with my plans, because
I took the pecuniary responsibility of the cost of what I ordered
until he could hear from you, and of course I do not want to incur
useless expense, but still more I do not wish any proceeding taken
as from me to be afterwards stopped. I will now describe as nearly
as I can what I have seen, and what I think.
As to the state of the ship, she is as straight and as sound as she
ever was, as a whole. She is resting and working upon rocks, which
have broken in at several places, and forced up perhaps 12 to 18
inches many parts of the bottom, from the fore stoke-hole to about
the centre of the engines, lifting the boilers about 15 inches and
the condenser of the fore engine about 6 or 8 inches; the
after-condenser, perhaps, half an inch. The lifting of the
fore-condenser has broken that air-pump, the connecting rod having
been unwisely left in, and the crank being at the bottom of the
stroke. Of course the air-pump could not help being broken; except
this, the whole vessel, machinery, &c., are perfect. I told you
that Hosken’s drawing was a proof, to my eye, that the ship was not
broken: the first glimpse of her satisfied me that all the part
above her 5 or 6 feet water line is as true as ever. It is
beautiful to look at, and really how she can be talked of in the
way she has been, even by you, I cannot understand. It is
positively cruel; it would be like talking away the character of a
young woman without any grounds whatever.
The ship is perfect, except that at one part the bottom is much
bruised, and knocked in holes in several places. But even within
three feet of the damaged part there is no strain or injury
whatever. I think it very likely that she may have started leaks
where she has been pounding away upon the rocks, but nothing more;
and as I said before, all above her 5 or 6 feet water line is
uninjured, except her overhanging stern; there is some slight
damage to this, not otherwise important than as pointing out the
necessity of some precautions if she is to be saved. I say ‘if,’
for really when I saw a vessel still in perfect condition left to
the tender mercies of an awfully exposed shore for weeks, while a
parcel of quacks are amusing you with schemes for getting her off,
she in the meantime being left to go to pieces, I could hardly help
feeling as if her own parents and guardians meant her to die there.
Why, no man in his senses can dream of calculating upon less than
three months for the execution of any rational scheme of getting
her off; and no man in his senses, I should think, would dream of
taking her across the channel in the winter months, even if he had
got the camels or floats fast. Of this I don’t feel so competent to
form an opinion, though I think I can judge, and I should consider
it a wanton throwing away of my shares if the Directors allowed
her to be taken out, even if afloat; but at all events I am
competent to judge of the probable time occupied in getting means
to float her, and I maintain that it would be absurd to calculate
upon less than two or three months. It is not therefore the mode of
getting her off that we ought to have been all this time thinking
of, but how to keep her where she is. I feel so strongly on this
point that I feel quite angry. What are we doing? What are we
wasting precious time about? The steed is being quietly stolen
while we are discussing the relative merits of a Bramah or a
Chubb’s lock to be put on at some future time! It is really
shocking.
Having expended a little of my feeling, I will tell you what I have
done, and what I should recommend.
First, instantly to disconnect the engines and air-pumps, and
remove all the working gear, so at least to leave the mischief to
the lower part. By the bye, the cylinders are not disturbed or hurt
in any way at present, but with the engines exactly at the bottom
of the stroke, and the connecting rods on, it is a wonder they are
not. If the air-pump had been disconnected it would not have been
broken. I have taken upon myself to order this.
Secondly, I suggested to Hosken, in which he quite agreed with me,
to take off all strain from her extreme stern. At present she has
cables out from this prodigious mass overhanging nearly 30 feet
from any part capable of bearing the strain.
I recommend his taking the chain cables through the ship’s side,
and making them fast with a spar or timber outside the starboard
side, about as far forward as the capstan. At present she is canted
seaward.
I thought she was better so than presenting the hollow lines of her
quarter to the sea, and both Hosken and Bremner came round to my
opinion.
Thirdly, there is a stream of water which now washes away the sand
from her bottom. I think it essential this should be diverted, and
kept so.
Fourthly, my plan for protecting her is totally different from any
that have been proposed, and if we have not such excessively bad
weather as would prevent anything being done, I believe it may
easily be done. And if done will, I am convinced, be perfectly
good; while any solid timbering, even if made, would, I think, be
most likely the cause itself of tremendous damage, if once beat by
the sea. I will only premise by saying that both Hosken and
Bremner came to the conclusion that it was the best thing that
could be done.
I should stack a mass of large strong fagots lashed together,
skewered together with iron rods, weighted down with iron,
sandbags, &c., wrapping the whole round with chains, just like a
huge poultice under her quarters, round under her stern, and half
way up her length on the sea side.
The detail of the mode, and the precautions of detail, I have not
time now to describe. I am as certain as I can be of anything that,
once made, such a mass of fagots would stand any sea for the next
six months, and the chances of making it (after one or two
failures, no doubt) are so good, that if properly taken in hand, I
look upon it as certain. I will write more fully to-morrow--in the
meantime I have ordered the fagots to be begun delivering. I went
myself with Hosken to Lord Roden’s agent about it, and I hope they
are already beginning to deliver them. Write and stop them or
not--if not, of course my responsibility ceases. I will write again
to-morrow, but let me know by train how we stand with the
underwriters.
This letter was a few days later supplemented by the following formal
report to the Directors, which was printed and circulated amongst the
proprietors.
December 14, 1846.
According to your request I have, as soon as my engagements would
allow of my leaving London, paid a visit to the ‘Great Britain,’
and I now beg to report to you the state in which I found the
vessel, and my opinion of the best means to be taken for recovering
the largest possible amount of the property invested in her. If I
state these opinions concisely, and without any qualifications, you
will not suppose that I have the presumption to think them
infallible, but merely that I am compelled, by the shortness of the
time left me to write to you, to avoid all circumlocution, and to
give you as simply and briefly as possible the opinions I have
formed--at the same time I am bound to say that I have not formed
them hastily, and that my convictions upon the several points upon
which I may express my feelings are very strong.
First, as regards the present state of the vessel, I was agreeably
disappointed, after the reports that had reached me, to find her as
a whole, and, independently of the mere local damages of which I
will speak presently, perfectly sound, and as strong and as
perfect in form as on the day she was launched.
In receiving this statement you must bear in mind the great
difference between an iron vessel and a timber-built ship. In the
former, parts may be considerably damaged or even destroyed, and
the remainder may not only be untouched, but may be left unstrained
and uninjured. In a timber ship this can hardly be the case; if any
considerable portion of a ship’s bottom is stove in, the timbers or
ribs completely across the ship and the planking longitudinally,
cannot fail to be strained to a very considerable distance in both
directions. You must therefore remove from your minds all
impressions derived from your experience of damages sustained by
timber-built ships in order to understand my statement, which is
strictly correct:--that, except the parts actually damaged, the
extent of which is comparatively small, the ship is perfectly
sound, and as good as at the hour when she struck. This soundness
and freedom from any damage extends from about the 5 feet water
line to the top (with the exception of the injury sustained by the
knocking away of the rudder post and a blow under the stern);
nearly the whole of the vessel is therefore sound: the principal
injury is in her bottom under the boilers and engines. The vessel
has evidently been thumping upon the rocks, and almost entirely
upon this part of the bottom from the first few days after she
grounded; and at present in all probability her whole weight is
resting upon this part; yet notwithstanding this she is perfectly
straight, and has not broken nor even sprung an inch in the whole
length. The boilers have been forced up about 15 inches, and one of
the condensers has been lifted about 8 inches, breaking the
air-pump. At present this is nearly the extent of the damage done;
all of which could easily be repaired if the vessel were in dock.
I will now state my opinion of the best means of recovering the
largest possible amount of the property which has been invested in
her. In this view I can only imagine two alternatives--the one to
break her up on the spot and make the most of the materials; the
other to get her afloat and into port, and restore her into good
condition, or sell her to those who would so restore her.
The first alternative may I think be discarded at once; the plates
and ribs of an iron vessel are difficult enough to convert into
useful materials for any other purposes, even in the midst of
workshops and with tools and appliances at hand. In such a place as
Dundrum Bay I do not believe the materials would pay the expense of
cutting up; the masts, spars, chains, &c., in fact the stores and
perhaps a few of the lighter part of the engines, might repay the
cost of removal, but the whole would certainly not amount to many
thousands; probably hundreds would be a safer estimate of the
amount to be realised clear of all expenses. To remove the vessel
and take her into port, and either restore her or sell her, is then
the only means of recovering any part of the whole of the capital
invested in this ship. If she is so brought into port she may be
worth, unrepaired, 40,000_l._, 50,000_l._, or 60,000_l._, according
to the opportunities that may offer themselves of employing her
usefully or selling her. The only question is, then, how at the
least expense, and at the smallest risk, is the vessel to be got
into port? But, as I will now endeavour to prove to you, the mode
of getting the vessel off the shore and into port is again quite
secondary to the consideration of how to preserve her where she is
so that she may be in a condition to be removed, _and to be worth
removing_, when the means of doing this are ready, and the proper
time is arrived for attempting it.
In the first place I assert unhesitatingly, that no man in his
senses and who thoroughly understands the circumstances of the
case, the weight and position of the vessel, the amount of the rise
and fall of the tide, and the draught of water around her, and the
extraordinarily exposed situation, would dream of calculating upon
completing the requisite means for floating her under three months.
_In the meantime the ship must be protected._ Even if it were
practicable to construct the necessary apparatus, and to float the
vessel to-morrow, it would be little short of madness to go to sea
with her at this time of the year; but I am doing wrong to discuss
a case which cannot arise. The vessel cannot, according to any
rational calculation of chances, be got off under three months, and
it is equally against all probability that, if left unprotected,
there would be anything worth taking off at that time. It is
useless, therefore, at this moment discussing the best mode of
floating the vessel; and I think, under such circumstances, it
would be most unwise hastily to determine upon any plan. The first
thing is to know whether there are any means of preserving the
vessel, and whether any such plans can be carried into effect at
some reasonable cost, which it may be worth incurring. I have
looked at the vessel, and considered the very exposed situation in
which she is placed (and a more exposed one could hardly be found),
and I am convinced that no fixed breakwater of ordinary
construction could be made at any reasonable expense, or in time to
prevent mischief. There is no depth of sand into which to drive
piles, and the rock is too uneven and broken to allow of any
framing being constructed and secured to it; and any framework
would be liable to be destroyed during the progress of its
construction, as that already attempted has been, and the timber
might be the cause of serious damage to the ship. The plan I should
recommend would at least be free from these objections, would be
comparatively inexpensive, and I am firmly convinced would be
perfectly effectual as a protection. At the same time few persons
who have not seen the effect of a sea beating against fagots will
share in that conviction; what I recommend is, to form under the
stern and along the exposed side of the vessel a mass of fagots
made of strong and long sticks, and used in the manner which has
been so successfully practised in Holland and elsewhere, for the
repair and protection of banks against the sea. The fagots should
be packed closely, and for a considerable thickness against the
ship’s side and up to the level of the decks, and secured with rods
run vertically through the mass, and chains laid horizontally and
binding the whole tightly to the ship. The heaviest sea has no
effect upon such a mass, and I believe the vessel would remain as
uninjured and indeed as unaffected by the sea as if in dock; 8,000
or 10,000 fagots, 300 or 400 fathoms of 1 inch or ¾ inch
second-hand chain cable, none of which need be lost, 300 or 400 ¾
inch rods sharpened at the ends, 1,000 bags to fill with sand, with
what stores you have on board, would suffice; and, if next coming
springs and the gales which have hitherto accompanied them are
safely passed, I cannot foresee any difficulty whatever in the way
of completing the protection I propose. Of course, in all works
dependent upon wind, weather, and tides, certainty cannot be
obtained; but of one thing I am quite certain, that no other plan
offers the same chance of success, or at so small a cost. I have
communicated to Captain Claxton the steps which I took, in
conjunction with Captain Hosken, for procuring the fagots before I
left Dundrum; I have also communicated to him the directions which
I gave with respect to the engines, &c., and it is unnecessary
therefore that I should repeat them. I will only recapitulate in a
few words the substance of the advice I have above given, and of my
reasoning. You have a valuable piece of property lying on a most
exposed shore; if preserved for a few months that property will in
all probability be worth 40,000_l._ or 50,000_l._; if neglected for
a few weeks longer it will probably be worth nothing. Can you, as
men of business, under such circumstances, waste your time at this
moment in discussing what you will do in three months hence, and
what plan you will then adopt to take your property to market, but
will you not rather first and immediately adopt decisive steps for
preserving that property, and then consider what you had best do
with it?
I have no wish to escape the responsibility of advising you, as you
request me to do so, as to my opinion of the best plan to be
adopted hereafter for removing the ship; but adhering to the
principle that I have laid down, I should decline to do so at
present, did I not see reason to fear that you might be losing time
and money by relying upon expectations which I am convinced would
be disappointed. I would strongly urge upon you not to place your
reliance upon any plan which depends upon floating the vessel by
camels, and taking her to sea unrepaired, and therefore entirely
dependent upon those camels. The immense breadth of these floating
camels, and the risk of taking such an unmanageable floating
ill-connected mass to sea, cannot have been correctly or
sufficiently estimated; and the certainty of the whole going to the
bottom, in the event of even a very moderate gale of wind or a
slight swell, has been apparently quite lost sight of. I am also of
opinion that the difficulty of lifting the vessel at all by
auxiliary floats has been underrated. The vessel has worked herself
about 5 or 6 feet into the solid rock and sand, and may very
probably get a little deeper before the time for lifting arrives.
She must therefore be lifted, say at least 4 feet to 4 feet 6
inches, before she could be got out of the dock she has made; and
the floating power must therefore be calculated at least to raise
her 5 feet 6 inches, so as to be quite sure of moving her. Now
there is not more than 10 feet water around the vessel even at high
water of ordinary springs, and it would be impossible to calculate
upon more than 9 feet as a certainty. No floating power worth
having can be got in the vessel, and the floating vessels must
therefore be capable of sustaining the whole weight, with a draught
when the vessel is lifted of only about 4 feet. The weight to be
sustained is 2,000 tons, and to do this with vessels drawing only 4
feet would require that they should be upwards of 30 feet in
breadth on each side, forming with the ship a total width of
upwards of 100 to 120 feet, and upwards of 300 feet in length. I do
not say that this operation is impracticable, but it is at least a
very difficult one, and must be almost entirely dependent upon
weather, and, unless in perfectly smooth water, a very hazardous
one. My belief and conviction is that the safe mode of proceeding,
and by far the cheapest, will be to lift the vessel by mechanical
means, to lay ways under her, and to haul her up sufficiently far
for her to be safe from the sea; to repair her just sufficiently to
make her water-tight, then launch and bring her to Liverpool or
Bristol. But, as I have before stated, there is time to consider
these points, if in the meantime we take steps to preserve the
ship. If the property is not even now worth protecting, it will
indeed be waste of money to be preparing at some considerable
expense to remove what will in all probability be only then a
valueless carcase.
If the Directors should determine upon adopting the course I have
recommended, I must remind them that the plan is one depending
entirely on the skill, the vigour, the aptitude for expedients, and
possibly, if bad weather should come on, and day after day the work
be destroyed, on the unwearying perseverance and determined
confidence in the plan of the person directing it, and the
sufficiency of means at his command.
I cannot conclude without doing justice to Mr. Bremner, whom I met
on board, and acknowledging the friendly and liberal manner in
which he discussed the various means to be adopted, and assisted me
with his valuable advice; and, although I may have somewhat
differed with him as to the advisability of attempting to float the
vessel away to sea without first repairing her, yet upon most
points we were perfectly agreed; and I firmly believe that if any
man could take her off (and if it would be prudent to let him do
so), Mr. Bremner’s great experience and sound practical knowledge
and good sense in devising any plan, and his energy and skill in
carrying it out, would ensure every chance of success which the
circumstances admit of.[133]
The Directors adopted Mr. Brunel’s suggestions; and, at his urgent
request, they appointed Captain Claxton to superintend the execution of
his plans.
Captain Claxton thereupon went to Dundrum, where he took sole charge of
all the subsequent operations.
The following is selected from the many letters written by Mr. Brunel to
Captain Claxton at this time.
December 29, 1846.
You have failed, I think, in sinking and keeping down the fagots
from that which causes nine-tenths of all failures in this world,
from not doing quite enough. Two and a half hundredweight of
sandbags, weighing barely one hundredweight [_in water_], would not
of course keep quiet a large fagot of five bundles, and two and a
half hundredweight of fire-bars, I should think, would only barely
do. The load must always be excessive, to make sure of a thing....
I would only impress upon you one principle of action which I have
always found very successful, which is to stick obstinately to one
plan (until I believe it wrong), and to devote all my scheming to
that one plan, and, on the same principle, to stick to one method,
and push that to the utmost limits before I allow myself to wander
into others; in fact, to use a simile, to stick to the one point of
attack, however defended, and if the force first brought up is not
sufficient, to bring ten times as much; but never to try back upon
another point in the hope of finding it easier. So with the
fagots--if a six-bundle fagot wont reach out of water, try a
twenty-bundle one; if hundredweights wont keep it down, try tons.
The able manner in which Captain Claxton carried out Mr. Brunel’s plans,
and suggested important modifications of them, is acknowledged by Mr.
Brunel, in a report to the Directors, written after the successful
completion of the breakwater.
February 27, 1847.
I beg to enclose Captain Claxton’s account of the proceedings at
Dundrum Bay during the time that he has been engaged in forming the
breakwater or protection to the ship in the manner recommended by
me.
Notwithstanding the great difficulties he has had to contend with
from almost incessant bad weather, with the wind blowing dead on
shore nearly the whole of the month of January, and consequently
preventing the tides from ebbing sufficiently out to allow of the
work being properly proceeded with, and notwithstanding the
occurrence of more than one storm at the most critical period of
the work, he has, as I fully relied upon his doing, succeeded in so
far protecting the ship, that she has been comparatively unaffected
by violent seas, which, there is no doubt whatever, would otherwise
have seriously damaged her. We may now calculate with tolerable
certainty upon preserving her without further injury until the
finer or at least more settled weather sets in.
In the work which Captain Claxton undertook, and has so
successfully completed, he has been compelled to vary very
materially the mode of proceeding first laid down; he has, in fact,
been obliged to adapt his plans to his means of execution, and
almost from day to day to devise modes of proceeding with only the
experience of the past day to guide him. Numerous unforeseen
difficulties have occurred, upon which he kept me daily informed;
and simple as my plan might have appeared to others, it required
much skill, contrivance, and unwearying perseverance to carry out
so many alterations and improvements as it progressed. I had relied
confidently on success when my friend Captain Claxton undertook the
work, and the result has fully confirmed my expectations.
It is now necessary to turn our attention to the best mode of
removing the ship. I hope in about a fortnight from the present
time to be able to give you some opinion upon this point, but it is
one requiring much consideration; and until I had the opportunity
of conferring with Captain Claxton on the subject, and also had
before me all the measurements and data which he has collected, it
was useless to attempt it.
* * * * *
The construction of the breakwater will be understood by the following
extracts from a report made by Captain Claxton to the Admiralty.
‘Great Britain,’ July 16, 1847.
...Mr. Brunel’s instructions to me were principally by word of
mouth; the difficulty to be got over, in his opinion, being the
foundation upon sand, varying in depth according to the points or
hollow of a substratum of rock, and according to the quarter from
which the wind blew.
The foundation could only be made at low water, and as fast as a
layer of fagots was laid, it was rapidly pinned down with iron
rods, bent at the heads, varying from 9 to 6 feet in length, and
driven to the rock under, loaded with stones quarried from the
nearest reefs, and upon these, the last thing as the flood came in,
chain cables, air-pump covers, fire-bars in large bundles, and the
ship’s guns were dropped, care being always taken to have the ends
of the chains, and the slings of other heavy matters, fast to the
ship. As the tide in smooth water began to recede, or in heavy seas
began to lose effect in striking, these iron weights were lifted,
and the fagots which were ready were ... placed; and the same
process followed tide after tide when the water ebbed sufficiently,
which upon the neaps it never did at all, and upon the springs it
only did for about an hour, unless there was either no wind at all,
or unless the wind blew off the land, or from the West round by the
North to ESE. It is necessary, to a proper understanding of the
nature of this really large work, to describe a bundle of fagots,
lest an idea should be formed that it is a small thing and easily
handled. They averaged 11 feet in length, and 5 feet in
circumference near the butts, which all pointed one way. When tied
in Lord Roden’s wood, many were 13 feet long, and none were taken
under 10 feet. A cart of the country with one horse could carry
about ten bundles when well lashed, and as they came down there was
rarely more than the head of the horse to be seen. Sixpence per
bundle, and sixpence for delivery, was the contract; the distance
at high water nine miles, at low water six miles; and our sailors
made them into large bundles of twos, threes, and fours; now and
then we experimented with bundles of eight or even ten, in the
middle of which were bags of sand (old guano bags), varying in
number, of 2 cwt. each, and sometimes as many as amounted to a ton
in weight. These large bundles stood if the water remained smooth;
but if, before we could build up to their height with smaller
bundles, and, as it were, prop or shoulder them fore and aft, we
were caught by a breeze and sea, we found them rolled up to high
water mark, or on spring tides four hundred yards; while some are
now being hove out of the sand entire, and with the sand bags and
sand complete....
Having got the foundation, on which, I may mention, we placed one
of the ship’s iron life-boats, 30 feet long, 8 feet wide, and 5
feet deep, and loaded her with stones, and which also, although
over bundles of fagots, went bodily down, until only the gunwale
was above the level of the strand, we began to build the part which
was to save the ship from the blows of the sea, and which I was
instructed by Mr. Brunel to bring up to a point to the ship’s
gunwale in the form of a large poultice, occupying the whole space
under her counter, the whole of the exposed quarter (the port
quarter), and inclining inwards from the outside, and declining
from the top to the same point forward, to the after end of the
bilge keel. I was to be, and was, as careful as I could be to
secure as well as to weight down as we built. Chains were secured
in many places to the lower bundles of fire-bars sunk in the sand
outside all, and these were brought into the arms of the screw, and
to ring bolts let into the ship; and rarely were two layers placed
without a repetition of the securing and weighting process all the
while we had chains to use....
We were frequently beaten; whole masses were capsized, but it was
found that even the foundation broke the ground swell, which,
instead of having a fair run as it has over the strand, seemed
stopped, and to break differently; and certainly the ship was daily
eased of the blows of the sea.... Finding the wind keeping on
shore, the fagots we placed shrinking, sinking, or settling down,
and, notwithstanding the weights and lashings, commonly breaking
away, I proposed to try spars. Mr. Brunel acceded, and recommended
my trying four long ones, to the heels of which were to be attached
chains with a spread of eight feet, the spars being pointed at the
heels, the slack of the chains, and the height at which they were
stopped to the spars, being intended to be sufficient to embrace
about a dozen bundles of fagots, the points of the spars sticking
through the foundation below the level of the sand. After placing
the first pair of spars at an angle from the gunwale of about 70
degrees, and before the second pair with its fagots could be got in
place, and after heaving them down tight with a tackle to each from
the head to the gunwale, a heavy sea came with the flood dead on,
and although the spars were seven inches square, they stood the
blows of the sea, bending in the middle full five feet when heavily
struck. This gave me the idea of green trees: firs being the first
that occurred to me; first because of their height, and next
because in Lord Downshire’s grounds at Dundrum the castle wood
consisted of them only, and lastly, because they were cheap and at
hand. The spars we fortunately placed, and which stood so well,
were American elm, a large balk of which had been sawed in four
lengths of 42 feet for framing, for Mr. Bremner’s breakwater....
The lengths required to allow the application of a tackle to the
head to heave them tight down to the gunwale, or to the
scuttle-holes of the ship, were from 45 to 50 feet. I found that
the firs of this length were scarce, and too fine at the head; but
on looking in Lord Roden’s wood, a better substitute was offered in
the form of beech trees of any size, and a contract was speedily
made, and as speedily completed; the carts of the country bringing
in one tree at a time, until about eighty were placed at the most
exposed point, the quarter, in three rows, the outside row at an
angle of 45 degrees. Beech-trees were found decidedly better than
firs, or, I believe, than any other description of tree, as their
weight was soon found sufficient to keep them in place without the
heaving down tackles. They can be got of great length, without
being so large and (carting, pointing, and handling considered) so
unwieldy a butt as firs, and they are of greater diameter aloft,
consequently stronger, and altogether tougher than firs. Having got
the whole stern surrounded, and having continued them at from 4 to
5 feet apart up to the bilge keel, or about 80 feet of the ship
from the screw, I applied smaller spars (easily and economically
obtained from the Tyrella domain, or within half a mile of the
ship) laterally and diagonally, and about a foot apart in the
former case, and 3 or 4 feet in the latter; the number about 300,
of all or any lengths between 15 and 30 feet. While this was about,
the fagot process was going on; and before that was completed, I
found the foundation with the boat, and its 40 tons of stones, and
even the spars, although pointed at the angles, indicated an
inclination to move forward through the sheer force of the rollers.
To check this, tackles were made fast to three warps out to
seaward, with two anchors to each, and brought to the spars with
four spans to the inner block. Thus twelve of the largest spars
were grappled, the falls taken on board, and all hove tight; the
whole of the spars having first been attached to one another by a
round turn of a half-inch chain with strong staples, and of course
by the lateral spars or spreaders, and their innumerable seizings.
Suffice it to say, as regards the spars, that when struck by
violent seas from half-flood to half-ebb, they bend in a body from
3 to 4 feet, and spring back after the blow; and this is, I
believe, the whole secret of the efficiency of the spar part of the
breakwater, which has stood the whole winter, only one having
broken, and that because the head took against the topsail yard,
lashed along stanchions of the rails as a hold-down for the tackles
attached to their heads. As a proof that this is the probable cause
of its standing so well, I may refer to Mr. Bremner’s breakwater,
which went with the first heavy gale and sea, although made of
balks of from 17 inches to 13 inches thick: also to our having
ourselves placed a pine spar 9 inches diameter down by the side of
the outside tree on the starboard quarter, and which broke in two
right in the middle with the first sea that struck it. The sea
struck very hard against the spars and framework, from which it was
received by the fagots without any shock to the ship worth speaking
of. With respect to the fagots, I could not find materials to go on
weighting down as we went on piling up.... I therefore ran the
remaining fagots up light. No sooner, however, was this done, and a
gale came on, than we were compelled to let go the lashings, and to
help some of the top ones to escape, as the whole of the unloaded
body rose and fell full three feet with the sea, and would have
done mischief to the spars and to the ship, by shouldering her
quarter, and twisting her. About 200 bundles broke away in this
gale. They were, however, all recovered, and placed further forward
and low down, and then loaded with stones; about one third of the
top space having after this been left open, or one third down from
the apex levelled. Shrinkage did much towards this, and breaking
in pieces a good deal; so it was not deemed advisable to fill that
space again.
About the 1st of May the progress made in lifting the ship by
tightening her from the inside, and by lightening her of everything
moveable, led me to believe that we should be about getting her off
towards the end of this month. I therefore felt that it was time to
begin removing the fagot portion of the breakwater.... The process
of levelling went on for about three weeks, when all above the
loaded portion was taken away. We commenced on that portion from
necessity, and found that by no contrivance of purchases and levers
could our ten men get up or out more than four or five bundles per
tide. This became, and even now is, a serious matter. We have got
up all our chains and weights, and nothing remains but the fagots
and stones, which are so embedded in sand as to form a mass which
is more difficult to move than granite rock would be, as we cannot
blast. Twenty labourers have been twenty-one tides at work, by
contract, and certainly they have made an impression; but it is not
lowered over two feet. The lower portion was made of furze bundles,
here called whins, and they are great collectors of sand, and only
come up at all by being cut to pieces. I mention this to show that
furze and fagots loaded with stones on sand 500 yards from
high-water mark, exposed to the sea, will form a foundation on
which a building of any weight might be erected....
Mr. Brunel informed me, when I undertook to carry out his views,
that there was nothing new in using fagots to stop breaches in
sea-walls, as in Holland; and that he saw no reason why they should
not stop the force of the sea in protecting ships as well, provided
they could be secured, and a foundation got. They were to be made
of alders, ash, holly, laurel, oak, or anything tough, to be cut
down, and made up green, to be placed with all their leaves on, to
be pointed to the sea at their butts; and inside the walls of them,
if I may so speak, whin (furze) bundles were to be weighted down,
the fagots placed in steps or rows of about 4 feet from the outside
to the ship’s gunwale.
* * * * *
As the summer came on, the mode of lifting and floating the ship had to
be decided. On this point Mr. Brunel wrote to the Directors:--
May 4, 1847.
You have heard from time to time from Captain Claxton of the result
of the means adopted by him for protecting the ‘Great Britain’ from
the effects of the sea, and which, I am happy to say, have been
quite successful; and you will have heard also generally from him
of the steps which we have since taken, preparatory to getting off
the ship.
I will now explain to you the object I have kept in view in these
preparations, and the course I should now advise you to follow.
After completing the works for the protection of the ship, and
before determining upon any mode to be recommended to you for
getting her off, I thought it would be desirable to lighten her of
all that could be easily removed, and to ascertain how much of the
vessel could be made water-tight, and what extent of buoyancy could
be obtained in the vessel herself, as, in my opinion, upon our
success in this would depend altogether the practicability of
lifting the ship by camels. If no great extent of buoyancy could
have been obtained, I should certainly have recommended lifting the
vessel by mechanical means, as I do not consider that, with the
draft of water which could be calculated upon around her on
ordinary tides, sufficient floating power by camels could be
obtained in an easy practicable manner. It was also quite possible
that we might succeed in making the vessel alone sufficiently
buoyant to lift high enough on the spring tides; and by shifting
her position, or by other means, to maintain the lift thus got, to
allow of getting under her bottom to repair her.
By great exertion nearly the whole of the compartments forward and
aft of the engine space, and part of the coal bunkers, have been
made tight; and if the tides had ebbed as low as usual, the other
bunkers and the boilers, fireplace and flues, would also have been
made water-tight by these last springs.
Unfortunately, from the direction of the wind and other causes,
these tides have neither ebbed nor flowed to their full extent;
still, the vessel has been lifted, and some of this lift has been
maintained, and if we were fortunate, it is evidently quite
possible that our utmost expectations might be realized, and
possibly the vessel might be lifted sufficiently to be made tight
without any external assistance. This, however, would be too much
to calculate upon, and the weight to be lifted having been reduced
to one-half what it was, and being capable of still further
reduction, the operation of lifting by camels becomes a much more
practicable undertaking.
I should now therefore recommend that application be made to some
parties who have had the most experience in such work, to lay their
proposals before the Directors; and that in the meantime we should
continue to make every effort to add to the buoyancy of the
ship....
I believe that, in such a case, quiet, sober consideration,
assisted by experience, and by careful examination of all the
circumstances on the spot, will be infinitely more valuable than
the most ingenious and brilliant schemes. And I believe we are most
likely to obtain these conditions by calling in a man like Mr.
Bremner, and leaving him to confer with Captain Claxton, and that
he should have the benefit of our advice and assistance, and then
lay his plans and proposals before the Directors.
Mr. Bremner and his son, assisted by Captain Claxton, made preparations
for releasing the ship. The system followed was that sketched out by Mr.
Brunel--namely, that of lifting the ship by mechanical arrangements, and
then making good the leaks. The difficulties they had to contend with
are graphically described in the reports which were sent almost daily by
Captain Claxton to Mr. Brunel, and which were afterwards printed by the
Directors at Mr. Brunel’s suggestion.[134]
The principal leak was stopped, and the ship’s head raised 8 feet 7
inches by ramming wedges and stones under her at high water. At last, on
August 27, the ship was floated, and Captain Claxton wrote to Mr.
Brunel:--
Huzza! huzza! you know what that means.... I made up my mind to
stop her at the edge of low water, and then examine and secure all
that might discover itself. The tide rose to 15 feet 8 inches. She
rose therefore easily over the rock, but was clear of it by only
just five inches, which shows how near a squeak we had--it was a
most anxious affair, but it is over. I marked 170 yards in the sand
and on our warp, and at that extent I stopped her.... I have no
doubt that to-morrow we shall see her free.
The following day they started for Liverpool. One hundred and twenty
labourers were hired to work at the pumps, but only thirty-six came on
board, and their services were unavailable, as they spent their time in
discussing how much they were to be paid. Consequently, when the ship
was taken in tow at 4 A.M. on the 28th there was 6 feet of water in the
engine room and 5 feet in the fore hold, and she was making 16 inches an
hour. Men from Her Majesty’s ships ‘Birkenhead’ and ‘Victory,’ which had
been sent by the Admiralty to assist, were drafted on board, and the
influx of water was reduced to four inches an hour. It was evident that
Liverpool could not be attempted, so they made for Strangford Lough. A
dense fog came on when they were off the entrance, and they pushed on to
Belfast Lough, where the ship was grounded. During the night she was
cleared of water, and the next day she started for Liverpool. The
landsmen who had been hired the previous night to work the pumps were
incapacitated by sea-sickness; and the ship was only kept afloat by the
exertions of Captain Claxton and the dockyard hands who had been sent to
assist in navigating her across. When she arrived at Liverpool she was
placed over a gridiron, on which she sank when her pumps were stopped.
Notwithstanding the successful result of the efforts made for her
rescue, the stranding of the ‘Great Britain’ in Dundrum Bay led to the
ruin of the Company; and she was some time afterwards sold to Messrs.
Gibbs, Bright, & Co., of Liverpool, by whom she was repaired, and fitted
with auxiliary engines of 500 nominal horse-power. On a general survey
being made, it was found that she had not suffered any alteration of
form, nor was she at all strained. She was taken out of dock in October
1851, and since that time she has made regular voyages between Liverpool
and Australia.
She is known as one of the fastest vessels on that line; and remains to
testify to the ability and wisdom of those who, more than thirty years
ago, were daring enough to build so large a ship of iron, and to fit her
with the screw propeller.
* * * * *
NOTE (p. 255).
_Dimensions of the ‘Great Britain’ Steam-Ship._
feet inches
Total length 322 0
The length of keel 289 0
Beam 51 0
Depth 32 6
Feet of water 16 0
Tonnage measurement 3,443 tons.
Displacement 2,984 "
_Dimensions of original Engines, &c._
Number of cylinders 4
Diameter of cylinders 88 inches
Length of stroke 6 feet
Weight of engines 340 tons
Weight of boilers 200 "
Water in boilers 200 "
Weight of screw-shaft 38 "
Diameter of screw 15 ft. 6 in.
Pitch of screw 25 ft.
Weight of screw 4 tons
Diameter of main drum 18 feet
Diameter of screw-shaft drum 6 "
Weight of coal 1,200 tons
CHAPTER X.
_STEAM NAVIGATION._ _INTRODUCTION OF THE SCREW PROPELLER INTO THE ROYAL
NAVY._
A.D. 1841--1844. ÆTATIS 36--39.
APPOINTMENT OF MR. BRUNEL TO CONDUCT EXPERIMENTS FOR THE ADMIRALTY
WITH VARIOUS FORMS OF THE SCREW PROPELLER, APRIL 1841--TRIALS WITH
THE ‘POLYPHEMUS’--OPPOSITION TO MR. BRUNEL’S EXPERIMENTS--TRIALS
WITH THE ‘RATTLER,’ OCTOBER 1843-OCTOBER 1844.
Soon after Mr. Brunel had taken the bold step of recommending the
adoption of the screw propeller in the ‘Great Britain,’ he was asked to
send a copy of his report to the Admiralty. He did so; and in the course
of a few months was invited to attend the Board on the subject of some
experiments their Lordships proposed to make.
An interview took place on April 27, 1841; of which Mr. Brunel gives the
following account:--
I attended the Board: Lord Minto stated that he wished a complete
experiment to be made on the applicability of the screw to
Government boats, and he proposed to place the conduct of the
experiments in my hands as a professional man. I stated that I
should have great pleasure in doing it, and should take great
interest in it, provided they intended to make a good experiment
and would place it entirely in my hands, without the intervention
of any Government officers, but that I should communicate direct
with the Lords, and of course with Sir E. Parry.[135] He said he
proposed to build a vessel and engines on purpose, and that he
particularly wished it to be left entirely in my hands, and took me
apart to the window to impress this last condition on me.
Within a fortnight of his appointment, Mr. Brunel invited Messrs.
Maudslay and Field and Messrs. Seaward to send him designs for the
engines: they were to have been of 200-horse power, with a stroke of 4
feet. The engines were to make a smaller number of revolutions than the
screw, the motion being communicated from the engine shaft to the screw
shaft by drums and straps. This arrangement was adopted in preference to
tooth-gearing, in order to facilitate the variation of the number of
revolutions, in the experiments with different screws.
The designs ultimately sent to Mr. Brunel for his approval were those of
Messrs. Maudslay and Messrs. Forrester. He reported to the Admiralty in
favour of Messrs. Maudslay’s engines.
Before drawing up the detailed specifications, Mr. Brunel was desirous
of procuring data for estimating the surface of the screw required to
obtain the same resistance as that offered by the paddles of a ship
similar to the new vessel. With this object he applied to the Admiralty
for permission to make an accurate trial of the performances of the
paddle steamer ‘Polyphemus’ at various speeds. This permission was
granted; the trial, however, was fixed for such an early day that Mr.
Brunel had barely time to make the preliminary arrangements, with the
assistance of his friend Captain Claxton.
When Captain Claxton arrived at Southampton, the day before the trial,
he found that there was no measured mile set out. He immediately hired
men, got chains, staffs, and flags, and set out both a nautical mile and
a statute mile. They made half a dozen runs each way with the
‘Polyphemus,’ noting carefully all particulars of speed, revolutions,
&c.; and the results obtained were considered very satisfactory.
On October 1, Mr. Brunel received information from the Admiralty (now
under the administration of the Earl of Haddington) that Messrs.
Maudslay and Field’s tender was accepted. The engines were immediately
put in hand, under Mr. Brunel’s supervision.
When they were approaching completion, he became anxious to learn
something about the progress of the ship which was to have been built
for them. Nowhere could she be found. The minutes were searched at the
Admiralty, and it was ascertained that the ship was ordered, but that no
ship had been laid down. This discovery, as might be supposed, excited
considerable surprise. Mr. Brunel was sent for to the Admiralty to see
Sir George Cockburn, the First Naval Lord. Almost the first words to him
were: ‘Do you mean to suppose that we shall cut up Her Majesty’s ships
after this fashion, sir?’--Sir George at the same time pointing to a
model of the stern of an old-fashioned three-decker, in which large
slices were taken off to give room for the screw, and the whole of the
lower deck exposed to view, thus making the application of the screw
look very ridiculous. On the model was written, ‘Mr. Brunel’s mode of
applying the screw to Her Majesty’s ships.’ Mr. Brunel smiled, and
denied its being his idea at all; he had never seen it before, and knew
nothing about it. ‘Why, sir, you sent it to the Admiralty.’ This also
Mr. Brunel denied having done. While an enquiry was being made as to
where the model came from, Mr. Brunel employed himself in effacing the
inscription with his knife. When the messenger returned, he reported
that the model had come from the office of the Surveyor of the Navy. He
was sent for, but did not appear. Mr. Brunel, to terminate this awkward
interview, pleaded business, and bowed himself out.
Mr. Brunel often told this anecdote, and spoke of the adverse influence
which had been exerted in some department of the Admiralty to prevent
the successful issue of these experiments.
Soon afterwards Mr. Brunel was informed that the ‘Acheron’ would be
prepared for the screw. He thereupon represented to their Lordships that
the ‘Acheron’ could not, from her full after-body and other defects, be
converted into such a ship as the Board had originally determined to
construct for trying the screw; and, indeed, her unfitness was admitted
by the authorities themselves.
To a letter on this subject, in which he stated that the attempt to
apply the screw propeller to the ‘Acheron’ would not answer any of the
objects which their Lordships had in view, Mr. Brunel received no reply,
and for the next four months was kept quite in the dark as to what was
going on. At length he made enquiries as to the cause of a treatment
which, he said, he had never before experienced from any public body.
These enquiries proving fruitless, he at last wrote to the Admiralty,
declining further interference, as it had appeared on investigation that
the condition on which he had accepted his position from Lord
Minto--namely, that he should have the entire superintendence of the
experiments--had not been observed.
On the receipt of his resignation, Mr. Brunel was summoned to the
Admiralty. He thus described his interview in a letter to a friend:--
Not a word was said about my complaint of the past, but they said
they wished me to continue the experiments, and that my screw was
to be tried first. I said that was not at all what would suit me;
that I would, if they wished it, conduct an experiment as
originally proposed; that I had no screw, that I was no competitor,
but an arbitrator in whom the Admiralty had perfect confidence;
that I was this or nothing. Then commenced a tedious fencing....
However, it ended in all parties being written to, and told that
they were to follow my directions, and that I was to proceed to
give such instructions as should enable a full experiment to be
made of all screws generally. I then requested that this time I
might have my instructions in writing.
In a few days Mr. Brunel received an official intimation that the
‘Rattler’ was to be adapted for the screw, under his directions.
The ‘Rattler’ was a vessel of 888 tons burden, 176 feet 6 inches between
the perpendiculars, and 32 feet 8½ inches beam.[136] She had been
commenced for a paddle-wheel steamer shortly before, and was of nearly
the same tonnage and midship section as the ‘Polyphemus,’ but she had
not the fine lines aft which were so important for the use of the screw.
She was not launched until April 13, 1843, just two years after Mr.
Brunel’s first interview with Lord Minto; and she was then delivered to
Messrs. Maudslay in the roughest possible state.
Except during the time that Mr. Brunel was prevented from attending to
business by the half-sovereign accident, he was in constant
communication with the dockyard authorities on matters relating to the
construction of the ship, with Messrs. Maudslay as to the
multiplying-gear and engines, and with Mr. F. P. Smith as to the forms
of the various screws to be tried.
The engines and screw were fitted in the ship, after considerable delay;
and, on October 24, 1843, Mr. Brunel reported on them in their completed
state. On the 30th, the experiments were commenced.
More than twenty trials were made between that date and the following
October, when the ‘Rattler’ went to sea, and Mr. Brunel could not of
course any longer personally superintend the experiments; but, except
on one or two occasions when his place was supplied by an assistant, all
the trials that were made during the first year were conducted in his
presence, and he transmitted the results from time to time to the
Admiralty.[137]
The performance of the ‘Rattler’ was found to be satisfactory; and the
position of the engines and screw being below the water line was so
pre-eminent an advantage, that in 1845 the Lords of the Admiralty
ordered more than twenty vessels to be fitted with the screw;[138] and
since that time it has gradually superseded the paddlewheel for ships of
war.
The services which Mr. Brunel rendered to the country during the whole
of these proceedings were given entirely without pecuniary recompense,
and in the face of opposition and discouragement; but he had the
satisfaction of knowing that he had been mainly instrumental, not only
in introducing the screw propeller into the mercantile navy, but also in
securing its adoption in Her Majesty’s fleet.
CHAPTER XI.
_STEAM NAVIGATION--THE ‘GREAT EASTERN’ STEAM-SHIP, FROM THE COMMENCEMENT
OF THE UNDERTAKING TO THE LAUNCH._
A.D. 1851--1857. ÆTATIS 46--52.
INTRODUCTORY OBSERVATIONS--THE AUSTRALIAN STEAM NAVIGATION
COMPANY--STATEMENT OF MR. BRUNEL’S PROJECT OF A LINE OF LARGE SHIPS
(JUNE 10, 1852)--ADOPTION OF HIS PLANS BY THE EASTERN STEAM
NAVIGATION COMPANY--EXTRACT FROM A LETTER DESCRIBING THE SCHEME
(JULY 1, 1852)--LETTER TO J. SCOTT RUSSELL, ESQ., ON THE FORM AND
DIMENSIONS OF THE GREAT SHIP (JULY 13, 1852)--REPORT ON MODE OF
PROCEEDING (JULY 21, 1852)--REPORT ON ENQUIRIES RELATING TO THE
DRAUGHT AND FORM OF THE VESSEL (OCTOBER 6, 1852)--REPORT ON THE
PROCEEDINGS OF THE COMMITTEE APPOINTED TO CONSIDER MR. BRUNEL’S
PLANS (MARCH 21, 1853)--TENDERS INVITED FOR THE SHIP AND
ENGINES--REPORT ON TENDERS (MAY 18, 1853)--PREPARATION OF THE
CONTRACTS AND SPECIFICATIONS--EXTRACTS FROM MR. BRUNEL’S MEMORANDA
(A.D. 1852, 1853, 1854)--LETTER ON HIS POSITION AND DUTIES AS
ENGINEER OF THE COMPANY (AUGUST 16, 1854)--LETTER ON AN ARTICLE IN
A NEWSPAPER (NOVEMBER 16, 1854)--REPORT ON THE UNDERTAKING
(FEBRUARY 5, 1855)--ARRANGEMENTS PROPOSED FOR OBTAINING
ASTRONOMICAL OBSERVATIONS--LETTER TO G. B. AIRY, ESQ., ASTRONOMER
ROYAL (OCTOBER 5, 1852)--APPOINTMENT OF MR. WILLIAM HARRISON TO THE
COMMAND OF THE SHIP--MEMORANDUM ON THE MANAGEMENT OF THE GREAT SHIP
(OCTOBER, 1855)--LETTER ON THE DUTIES OF THE CHIEF ENGINEER (MARCH
19, 1857)--SUSPENSION AND RESUMPTION OF THE WORKS.
Mr. Brunel’s earlier labours in connection with the progress of Ocean
Steam Navigation have been described in the chapters on the ‘Great
Western’ and ‘Great Britain’ steam-ships.[139] The ‘Great Eastern’ is
but the result of the application, under different circumstances, of the
same principles which had guided him in his previous under-takings, the
practical working out of the ‘idea which he had frequently entertained,
that, to make long voyages economically and speedily by steam, required
the vessels to be large enough to carry the coal for the entire voyage
at least outwards; and, unless the facility for obtaining coal was very
great at the out port, then for the return voyage also; and that vessels
much larger than had been previously built could be navigated with great
advantage from the mere effect of size.’[140]
In 1851, four years after the release of the ‘Great Britain’ from
Dundrum Bay, Mr. Brunel became again connected with the construction of
steam-ships. In that year he was consulted by the Directors of the
Australian Mail Company upon the class of vessels which it would be
advantageous for them to purchase, in order to carry out their contract
for the conveyance of the mails to Australia. He advised them to have
ships of from 5,000 to 6,000 tons burden, in order that they might only
have to touch for coal at the Cape.
Some of the Directors would not hear of so startling a proposition; but
they nevertheless asked Mr. Brunel to become their Engineer; and he
retained the post till February 1853. Two ships were built under his
direction by Mr. J. Scott Russell--the ‘Victoria’ and the ‘Adelaide.’
It was, no doubt, his connection with the Australian Mail Company that
led Mr. Brunel to work out into practical shape the idea of ‘a great
ship’ for the Indian or Australian service, which had so long occupied
his mind; and it appears that in the latter part of 1851 and the
beginning of 1852 he devoted much time and thought to the subject. He
collected facts relating to the trade with India and Australia which
demonstrated the advantages to be gained by a rapid and direct
communication for the conveyance of passengers and troops, as well as of
merchandise. It was with these enlarged views that Mr. Brunel entered
upon the construction of the ‘Great Eastern.’ He writes in February
1854, ‘In February and March 1852 I matured my ideas of the large ship
with nearly all my present details, and in March I made my first sketch
of one with paddles and screw. The size I then proposed was 600 × 70,
and in June and July I determined on the mode of construction now
adopted of cellular bottom; intending then to make the outer skin of
wood for the sake of coppering.’
In the spring of 1852 he communicated the results at which he had
arrived to Mr. John Scott Russell, Captain Claxton, and other scientific
friends, and also to several Directors of the Eastern Steam Navigation
Company.
This Company had been formed in January 1851 for the purpose of
establishing an additional line of steam communication by the overland
route, for the conveyance of mails, passengers, &c., between England,
India, and China, with a branch to Australia. However, in March 1852 the
Government determined to grant the contract for the whole service to the
Peninsular and Oriental Company. The Directors of the Eastern Steam
Company were therefore obliged to report to their shareholders that the
object for which the Company had been incorporated could not be carried
out.
At about this time Mr. Brunel’s scheme was brought before the Directors,
and he submitted to them a detailed statement of his project.
After describing the size and capacities of the vessels then used on the
route between England and the East, and the amount and cost of the coals
they consumed, he continued:--
June 10, 1852.
The same amount of capital and the same expenditure in money for
fuel now required for a line of ships of the present dimensions
would build and work ships to carry in the year double the number
of passengers, with far superior accommodation, and in about half
the time, and two or three times the amount of cargo; the whole
difference being produced simply by making the vessel _large enough
to carry its own coal_, exactly as when the ‘Great Western’ was
projected for the New York line, the passage had been considered an
impossible one for steamboats, or, if possible, only at a total
sacrifice of all return for the cost. Certainly, no steamboat then
built could get across except by a chance fair weather passage, and
then only by being completely filled with coals and leaving no room
for passengers or cargo. Simply by building a ship of the size
necessary to take the coal, over and above the accommodation
required for a due number of passengers and a reasonable quantity
of cargo, the passage was rendered perfectly easy and certain, and
has since become a mere matter of course, and an ordinary and
profitable trading voyage.
The increased size, instead of being a disadvantage, was found, as
predicted by the projectors, to be a great benefit, and gave
increased speed, even beyond that proportionate to the power; and
this steamboat, built in 1836, is still as good as any of her size
afloat.
Nothing more novel is proposed now, but again to build a vessel _of
the size required to carry her own coals for the voyage_. The use
of iron, which has since 1836 become common, removes all difficulty
in the construction, and the experience of several years has
proved, what was believed before by most unprejudiced persons, that
size in a ship is an element of speed, and of strength, and of
safety, and of great relative economy, instead of a disadvantage;
and that it is limited only by the extent of demand for freight,
and by the circumstances of the ports to be frequented.
A Committee was appointed to confer with Mr. Brunel and with Mr. Scott
Russell, ‘who was fully acquainted with all Mr. Brunel’s plans, and had
ably assisted him in maturing them.’[141]
The Committee reported to the Directors that they had met on the day
after their appointment, when, Mr. Brunel being unavoidably absent, Mr.
Russell had attended and entered into a very full explanation of Mr.
Brunel’s plans, and that a long investigation of his proposition had
taken place; that a few days later they had met again, when Mr. Brunel
attended, and that after a further and most satisfactory investigation,
they had come to an unanimous decision in favour of the scheme. This
resolution was adopted, and Mr. Brunel was appointed Engineer to the
Company.
The following extracts from his reports and correspondence carry on the
narrative till the date of the next meeting of the shareholders
(December 1, 1852), when the details of the project were laid before
them:--
_Extract from a Letter describing the Scheme._
July 1, 1852.
The principle is, as I explained to you, a very simple one--that of
building ships to carry their own coals, instead of incurring large
expenses and great delay in coaling at numerous intermediate
stations; and the result is a large vessel certainly, but one
which, at the same cost of fuel as is now required for small ones,
has, besides that room, for 4,000 or even 5,000 tons (measurement)
of cargo, and as many passengers as offer. Thus the capital
embarked in the one vessel is not so great in proportion to the
tonnage space for cargo as the capital embarked in several smaller
vessels carrying the same amount; while the current expenses are
greatly less, and the speed, and economy of time by that speed and
by avoiding tedious stoppages, greatly in favour of the large one.
Practical men concur with me, not merely in the practicability of
constructing the vessel, but in the great advantage as regards
speed, seaworthiness, and safety resulting merely from the
increased size; while all the mercantile men concur in the opinion
that if goods can be carried direct in thirty to thirty-five days,
the certainty of freight ensures a return far beyond all present
proportion of return to cost.... On these points, of course, I
quote only the opinions of the Directors. On the mechanical part I
offer my own opinion, and may quote those of the first practical
men of the day--Messrs. Maudslay, Messrs. Watt and Co., and J.
Scott Russell, all of whom have assisted me in the project, and are
prepared to join in it.
_Letter to J. Scott Russell, Esq., on the Form and Dimensions of the
Great Ship._
July 13, 1852.
The adoption of this plan being now determined upon, we must
proceed to determine the details, and the first step unquestionably
is the determination of the size and form of the ship. Now, in
preparing the general design, I think the following conditions
should be strictly complied with. If any of them appear to involve
any great sacrifice in cost, or to involve any other peculiar
difficulties, these difficulties can be considered afterwards; but
the wisest and safest plan in striking out a new path is to go
straight in the direction which we believe to be right,
disregarding the small impediments which may appear to be in our
way--to design everything in the first instance for the best
possible results strictly according to the principles which theory,
so far as it is supported by practice, teaches us, and without
yielding in the least to any prejudices now existing unsupported by
theory and practice, or any fear of the consequences; we can then
afterwards weigh and balance deliberately the advantages of
adhering to or giving up this or that particular part, or modifying
dimensions, either from motives of economy, or as yielding to
public opinion from motives of policy.
In determining the lines of the ship, for instance, I should adopt
that which we have reason to believe the best possible without any
concession, or any compromise or regard to any assumed difficulties
of construction, or regard to assumed opinions; these difficulties
will very likely vanish afterwards if disregarded in the first
instance, as in the case of the continuous curve, in which my fresh
ideas had the advantage even of your much greater knowledge,
hampered by a little preconceived idea. With respect to the size,
to arrive at it by constructive calculations from the fixed
conditions that we can lay down is perhaps possible, but rather
difficult, and I think we know sufficiently nearly now what the
minimum size must be to work upon; that, and a trifling alteration
afterwards in the scale, will suffice to bring it to the exact
required capacity.
The positive conditions, then, are a maximum draught of water of 24
feet, when leaving the Hooghly with the coals for the voyage home;
and the capacity must be at least 21,000 tons of displacement at
this draught of 24 feet.
I think you will find that to effect this comfortably you must give
a length of 650 feet at least, and an extreme breadth of 80 feet,
but this beam of 80 feet requiring no fuller entrance than you
would make with a beam of 70 feet, the 80 feet being obtained
entirely by continuing a gentle curvature throughout the whole
length, instead of having any parallel lines.
If the experiments upon the friction of surfaces turn out as I
hope, and give us reason to expect a very much less resistance from
a copper surface than that now created by painted iron, I suspect
we may be led rather to increase our length and diminish the
proportion of beam; but this is a very serious question, not
entirely dependent on the consideration of the form of least
resistance including friction, but also materially affected by the
consideration of the advantages of the extreme steadiness of motion
which length seems to give. It is a subject which must be well
discussed and well considered, with the assistance of all those
whose opinions and experience are likely to be of use to us. My own
impressions, I confess, derived from considering the cases which we
have, even after the striking result of the ‘Ocean Queen,’ are that
positive length, independently of relative length, has much to do
with it. When I see that the ‘Great Britain,’ although with a beam
of about one-sixth of her length at the water line, and a midship
section favourable to rolling, is nevertheless steady, I must
conclude that positive length may compensate very greatly for a
relatively wide beam. Now, we shall unquestionably have abundance
of positive length. We must then be careful not to sacrifice much
to keep a small beam, without being very sure that there are very
great advantages; and, except for the assumed advantages of the
long parallel or equal bearings, the form of least resistance,
including friction, with a draught limited to 24 feet, and a
required displacement of 21,000 tons, would, I apprehend, give us a
beam nearer 90 feet than 70 feet. I should like to know exactly
what the proportion would be without regard to the theory of the
long narrow parallel forms; and then let us consider how much, if
anything, should be sacrificed to attain the advantage assumed to
be attained by relative length.
Let us therefore have at once the draft of a vessel of 21,000 tons
displacement at the 24 feet water line, and of such form as will in
your opinion give the greatest speed in smooth water, without
seeking to make it narrow.
We must, of course, also bear in mind the comparative weakness of
form caused by length, and the consequent increased thickness of
material required, besides an actual increase of surface, involving
a very considerably greater quantity and weight of material in the
ship, which last consideration is very greatly in favour of breadth
of beam; for I think you will find that the quantity of iron in
two ships of 600 and 700 feet in length respectively, with the same
displacement and the same ultimate strength to resist strains, will
be fully in the ratio of their length.
_Report to the Directors on Mode of Proceeding._
July 21, 1852.
Since the adoption by the general meeting of the plan recommended
by the Directors, I have been engaged very constantly in maturing
the details of that plan, and considering the course which it would
be necessary to follow in order to carry them out in the surest,
safest, and most efficient manner.
The steps which are about to be taken are unquestionably in the
right direction, but they are considerable ones, and must be taken
with deliberation and certainty, and without leaving anything
doubtful; and, when determined upon, they must be followed up with
decision.
Although you will probably determine upon constructing not less
than two vessels in the first instance, yet they must both be
proceeded with at once, and must in fact be exact duplicates of
each other. The success of the two, therefore, depends upon that of
each; there can be no average struck in such a case, but the two
ships must be designed and executed on such principles and with
such perfection that no doubt can exist of the result.
By well considering all that has been done, by selecting all that
has been most successful, and by a judicious application of such
results to the peculiar circumstances of our case, all this
certainly can, I think, be assured, but it can be assured only by
proceeding with the caution and the decision which the
circumstances demand.
In the first place, as to the designing of the whole, the principle
being determined upon, much may be ascertained by mere calculation,
but for these calculations data are required, which nothing but
experience can furnish. I have, therefore, availed myself of the
assistance of those most competent to afford the required
information. I have called in to my assistance the gentlemen whom I
had already named to you as best able to give strength to our
position by the value of their opinions, and best able to execute
the various parts of the work with that experience and perfection
which are essential to our success.
With respect to the form and construction of the vessel itself,
nobody can, in my opinion, bring more scientific and practical
knowledge to bear than Mr. Scott Russell. As to the proportion of
power to be adopted, the form and construction of the engines,
screw, and paddles, besides Mr. Scott Russell, I have had the
benefit of the deliberate consideration and advice of Mr. Field, of
the firm of Maudslay and Field, and of Mr. Blake, of the firm of
Watt and Co. I have written also to my friend Mr. F. P. Smith, to
whom the public are indebted for the success of the screw, for his
advice on the subject. With such assistance I think we may rely
upon the certainty of being able to design and to execute all that
is best in the mechanical and ship-building department. In the
naval department I have had the opportunity also of consulting two
gentlemen, Captain Claxton and Captain Robert Ford, who possess
special knowledge and experience on the subject. I have had several
conferences with all these gentlemen, I have explained fully my
views, and, with their assistance, settled preliminarily some of
the principal points of detail. What I should propose to the
Directors now is, that with that assistance I should proceed to
prepare in detail the design of the ship, and the exact dimensions
and form of the engines; that, in the meantime, I should obtain
information upon certain points which will govern you as to the
mode of contracting for the construction of the ships, and also
that I should be authorised to adopt some means of determining one
or two most important points which must govern some of the
principal dimensions.[142]
_Report to the Directors on Enquiries relating to the Draught and Form
of the Vessel._
October 6, 1852.
Since the date of my last letter to you, recommending that certain
enquiries and investigations should be set on foot to determine
several points which would materially influence the plans I should
have to submit to you, many circumstances have occurred to delay
these investigations. Not having sent any competent person
expressly to Calcutta to ascertain with certainty the draught of
water that might be adopted, I have endeavoured to obtain as much
information as possible upon this point from persons capable of
affording it, who might be in England.
Several very competent men, captains of long experience in that
particular navigation, and even local pilots of the first standing,
happened to be within reach, and I have had personal communication
with these gentlemen. Notwithstanding, however, these fortunate
opportunities of obtaining information from the best existing
authorities, we are left in pretty nearly the same state of doubt
as to the maximum depth as we should be by a mere inspection of the
charts, the opinion of very competent men varying so much as to fix
this maximum as low as 21 and as high as 23½ and even 24 feet. They
all concur, however, in fixing Diamond Harbour as the point in the
Hooghly which may easily be reached, but beyond which it would be
almost impossible to go.
A question as to the extent of swell which in so large a ship might
be given to the sides, increasing the capacity without materially
increasing the resistance, involved one of the experiments to which
I referred in my former letter; these experiments have been made,
and the result, such as it was, of the enquiries before referred to
as to the navigation of the Hooghly, led me to direct the
preparation of draughts of three different models of ships, and
upon further consideration of these three, and under the
circumstances, I have come to the conclusion of recommending one
which will have the following dimensions:--namely, 670 feet in
length, 85 feet beam, and a deep water draught of 30 feet.
Such a vessel would be able to carry her own coal for the voyage
home out of the Hooghly with about 23 feet draught; but if between
now and the period when the exact arrangement must be determined,
it is found expedient not to attempt so great a draught in the
Hooghly, the same vessel will, by coaling at Trincomalee on the
return voyage, be exactly adapted to work out of the Hooghly with a
good cargo of goods and coals for Trincomalee with only 20 to 21
feet draught.
I have been in communication with the eminent engine builders whose
names I have mentioned on a former occasion, and with Mr. F. P.
Smith, the inventor of the screw propeller. Some trials and
investigations are still in progress to determine the relative
advantages of a copper and iron bottom, on which question may
depend the arrangements which may be requisite to provide for
docking or rather laying up for cleaning, and when these points are
determined I shall be prepared to lay before you a complete design
of ship and engines for your consideration.
Efforts were made to induce the public to assist in carrying out the
project. In February 1853, the Chairman (the late Mr. Henry Thomas Hope)
and several of his colleagues formed themselves into a committee for the
purpose of communicating with Mr. Brunel on the subject of his plans,
and reporting to the Board thereon.
The results of this conference were embodied in the following report
which Mr. Brunel addressed to the Directors:--
_Report on the Proceedings of the Committee._
March 21, 1853.
To enable the Committee to arrive at a correct conclusion on this
difficult question, I had gone through rather lengthy calculations
of the minimum dimensions and the comparative estimated cost of the
ships which would in each case answer the purpose under the several
different circumstances which might be assumed; and the results of
these calculations were laid before the Committee, and the relative
advantages and disadvantages of each assumed case discussed....[143]
After much discussion, and comparing the probable receipts with the
estimated expenditure, and allowing fully for interest of capital
embarked, I think it appeared to the Committee that as a mere
mercantile transaction, and with reference only to the Australian
trade, the larger vessel would be the most economical, showing not
merely the means of securing the largest return, but involving an
actual diminution of annual expenditure....
The Committee were unanimously of opinion that the largest size of
the first class would be the best, and would in every way answer
the objects of the Company.
The dimensions arrived at by calculation for this ship would be in
round numbers, 670 feet long, 80 feet beam.
This sized vessel would combine most of the advantages which we
seek to obtain. It would carry coal to Diamond Harbour and back to
Trincomalee; it would afford room for about 800 separate cabins
larger than those now fitted up in packet ships, with large
saloons, capable of accommodating 1,000 or 1,500 first and
second-class passengers; and would carry 3,000 tons weight of
cargo, without making any allowance for that increase of speed
proportionate to the mere increase of size of which we see every
day fresh proofs; the average speed of the ship, with the proposed
power of engine and calculated consumption of coal, would be 14
knots at the average, making the passage out in 34½ days, say 36;
but with that increased speed which has been shown to take place
with increased dimensions, we may speculate upon the voyage being
performed in 30 days.
This same vessel, fitted up for the Australian voyage, and loaded
deeper, would carry coals to Australia and back, would take out
3,000 passengers easily, and a small amount of cargo only, but
could bring back any amount that could be conveniently collected,
or if provision were made for taking in 3,000 or 4,000 tons of coal
in Australia, that additional amount of cargo might be taken in the
passage out. The passage out to Port Philip should be made easily
in 36 days, and home by Cape Horn in the same time.
The Committee having come to the conclusion that this class of
vessel would best fulfil the several conditions which the
circumstances imposed, I have been engaged in determining the
several details consequent upon this selection of size, and have
put in hand drawings of the ship, which will enable me to arrive
more correctly at the cost, and will enable us to obtain tenders
for the construction. These details involve a great deal of study
and consideration, and the making of the drawings alone requires
some considerable time, so that I do not think much advance can be
made under three weeks from the present date, but I will endeavour
to expedite the work as much as possible.
Mr. Brunel was authorized to continue his communications with
engine-makers and ship-builders, and to invite tenders.
After very detailed and careful calculations of the smallest capacity
that would secure the attainment of the objects sought for, the
dimensions of the vessel and the power of the engines were finally
determined; tenders were received from Mr. Scott Russell, Messrs. Watt
and Co., and Messrs. Humphrys and Co. for both sets of engines, and from
Mr. Russell for the construction of the hull of the ship and for placing
her afloat.
A meeting of the Directors was held on May 18, when Mr. Brunel submitted
the various tenders he had received. The Board agreed to adopt his
recommendations, and to accept the tenders of Mr. Scott Russell for the
ship and paddle engines, and that of Messrs. James Watt and Co. for the
screw engines.
The following report, which Mr. Brunel placed before the Directors,
gives a detailed account of the steps he had taken to procure the
tenders, and the grounds on which he had formed his judgment of them:--
_Report on Tenders._[144]
May 18, 1853.
According to your instructions, I applied to the several parties
with whom I had previously been in communication on the subject of
the engines and ship, for tenders for their supply. As regards the
engines, I drew up a short specification, defining generally what
was required, and leaving the parties to make their own designs and
propose to me the form of engine they would adopt.
With respect to the ship, where no such variation could be
permitted, I have had very detailed drawings and specifications
prepared.
Copies of the specifications are annexed.
In defining the power of the engines and boilers, I have, in
conformity with my own views and of those of several of the
Directors, who have expressed themselves strongly on the subject,
required a very full amount of power, without naming the nominal
horse-power, which is a very vague mode of defining anything but
the cost which by custom is made dependent upon that nominal power;
but I have defined dimensions of parts and surface of boilers which
will ensure the means of exerting a very large amount of power.
As regards the ship, I have not spared strength of materials, and
have required the best workmanship.
The result of this application for designs and tenders is, upon the
whole, very satisfactory, although two of the parties from whom I
had hoped to have received proposals have not been able to send
any....
Mr. Blake, of the firm of Watt and Co., and Mr. J. S. Russell and
Mr. Humphrys, have, as I had before reported, devoted much
attention to the subject: from these gentlemen I have received
distinct well-considered designs of the screw and paddle-engines.
I have been in frequent communication with these gentlemen, and
have seen their plans while in progress, and have made my
suggestions upon them, and assisted more or less in maturing them,
and at all events in preventing the adoption of any principle or
arrangement that I should afterwards object to. Notwithstanding
this, the three designs, particularly for the screw engines, are
totally dissimilar, and I am placed in the difficulty of having to
choose between three totally different plans, each designed by
skilful and experienced men, and each possessing many known and
acknowledged advantages.
I should also observe that, although I have known the general
arrangement which each would adopt, I did not receive the plans or
the tenders which I now forward until last evening, and that of Mr.
Humphrys as late as 10 o’clock this morning, and that I have not
therefore had time to draw up any very detailed report upon them.
The following are, however, the principal considerations which
influence me in the selection which I am disposed to recommend.
It must be borne in mind that the screw engines will be the largest
engines that have yet been made. The principal part of the
propelling power of the ship will be thrown upon the screw; and
upon these engines therefore will mainly depend the performance of
the ship, and particularly upon their constant never-failing
working, probably for thirty or forty days and nights, must depend
the certainty of the ship’s performance.[145] Under all these
circumstances, the compactness and stiffness of framing, the
greatest possible simplicity of construction, and the fewest
possible number of parts, and, finally, the absence of any novelty,
however promising, that can introduce any unforeseen difficulties,
are conditions which would outweigh in my mind many advantages that
might, and I think would, be attained by several arrangements which
have been suggested.
All the designs now submitted comply with these conditions to a
very considerable extent ... but the extreme simplicity of Mr.
Blake’s engine leads me to prefer it.
As regards the paddle engine, I unhesitatingly give the preference
to that proposed by Mr. Russell. I believe it to be as simple an
arrangement as can be adopted for engines with such a slow motion
and so long a stroke as these must have, and the single crank in
the centre I consider a great advantage....
As regards a contract for the ship, I have found it more difficult
to proceed in the ordinary course. The conditions which we must
ensure of quality of workmanship and execution, under close
inspection and within reach of one’s own supervision, are not
easily attained; and, though as a matter of course readily promised
and undertaken by all ship-builders, they are rarely secured. It is
essential also that the ship should be built where the engines can
be readily fixed on board before launching, and in a yard which can
be devoted to the purposes of the ship, and whence the launching
can be effected with the engines and boilers on board.
All these are conditions not easily secured. I have been in
communication with one or two parties, and the result is a tender
from Mr. J. Scott Russell, which I enclose, and which has in fact
been framed upon my calculations. Owing to the recent rise in iron
it is somewhat, but not materially, above the amount at which I had
originally estimated the vessels; but the tender, founded upon the
supposition of two such vessels being ultimately ordered, is as
nearly as may be the same as my original estimate, and upon the
whole I consider the tenders both for engines and ships very
satisfactory and confirming fully our previous calculations.
These tenders do not include, in the case of the engines, either
the screw itself or the paddle wheels, nor, in the case of the
vessel, the cabin fittings, masts, and rigging, boats, or stores. I
should estimate these roughly at 50,000_l._ more,--at least such an
allowance ought to be ample; but these details will require a great
deal of consideration, and could not be included in the original
contracts; while at the same time they can mostly be better and
more economically supplied by competition or by arrangement with
the special makers of the respective articles....
During the next six months Mr. Brunel was engaged in preparing the
formal contracts and specifications. These documents were settled with
much care, and after frequent communications with the contractors, who
consented to the insertion of clauses which gave the full control and
supervision over every part of the work to the Engineer, with very large
powers of interpretation. They required, however, that, should Mr.
Brunel cease to act as Engineer, any disputed point should be settled by
arbitration, and not by his successor.
Besides the delay occasioned by the magnitude and novelty of the
undertaking, there were other difficulties which helped to postpone the
commencement of the works. The Directors were unable, under their
charter, to enter into any contracts until a certain amount of their
capital was actually paid up; and, as several shareholders had retired
when the change of plans was determined upon, it was no easy work to get
the shares taken. That this was eventually accomplished was due mainly
to the exertions of Mr. Brunel and Mr. Charles Geach, one of the
Directors.[146] ‘Could I have foreseen,’ Mr. Brunel writes, ‘the work I
have had to go through, I would never have entered upon it; but I never
flinch when I have once begun, and do it we will.’
Several times they nearly broke down, but at length the contracts were
signed, and on the same day, December 22, Mr. Brunel gave the formal
notice to the contractors to proceed with the works. ‘After two years’
exertions (he wrote), ‘we are set going, the contracts entered into, and
the work commenced.’
_Extracts from Mr. Brunel’s Memoranda_, A.D. 1852-1853.
_July 11, 1852._--The dimensions I commenced with in March last, of
650 × 70 × 30 appear after all to be not far wrong, according to
present views. I make them now 700 × 70 × 24 about; but much
depends upon the last dimension, the draught. If another foot or
two can be safely taken it will be of great advantage.... With this
size of vessel, having a midship section of about 1,800, and a
length of 700, I assume a nominal horse-power of about 2,500. The
first question of importance is, in what proportion shall this be
divided between the screw and paddles?... My present impression is
to halve the power between the two.
In both the engines every known means must be adopted to secure
efficiency:--1, An excess of boiler power; 2, expansion
permanently, say at ⅓; 3, steam of not less pressure than 20
lbs., and I should prefer 25 lbs.; 4, that cylinders, particularly
top and bottom, slide chest, and steam pipes, be all jacketed, and
the jacket supplied with steam from an auxiliary boiler of at least
10 lbs. more pressure than that of main boilers; and it would be
very desirable to make some experiments to determine whether it is
not worth having a heating apparatus to heat the steam immediately
before it enters the cylinders.[147]
_July 17._--After a long conference with Mr. Field, I continue of
the opinion that it would be well to apply about three-fifths of
the power to the screw and two-fifths to the paddles, and probably,
as the vessel gets light, diminishing a little the expenditure of
power on the paddles, and keeping up the full power on the screw.
Mr. Field is not in favour of increasing the pressure of steam
beyond 12 lbs. or 15 lbs., on the ground that all the mechanical
difficulties increase rapidly without a corresponding advantage,
particularly where size and weight are not so important. There
seems much truth in this.... The possible advantages of a slight
increase are not sufficient to justify the risk of the possible new
difficulties in a work on so large a scale. Nothing uncertain must
be risked. These arguments do not apply to the jacketing and
heating, which Mr. Field also deprecated, or rather discouraged,
simply on the ground of the trouble and difficulty of effecting it,
but he admitted that all experience went to show the advantages of
it; and as to the difficulties, which I could not see, they involve
no other risk than that of being useless: they cannot do mischief.
The heating of the top and bottom of the cylinders, I think, must
be particularly important in a short-stroked engine working
expansively. In a cylinder of 80 inches diameter and 40 inches
stroke, having regard to the _time_ of contact, the area of the
bottom will be nearly equal in effect to the surface of the
cylinder.
_July 19._--After much consideration, I think I feel satisfied that
the best construction will be to have strong bulkheads every 30
feet or thereabouts, this distance being dependent on what is
required for one set of boilers and its stock of coals; these
bulkheads being carried right up wherever practicable--I think
every alternate one may be--and then place the main ribs of the
ship, and even at least two main deck beams, _longitudinal_ instead
of _transverse_.
_February 2, 1853._--Several drafts of ships have been made and
much consideration given to the subject, and frequent discussions
with various parties. The result of all is that my present views
are as follows:--
The ship, all iron, double bottom, and sides up to water line, with
ribs longitudinal like the Britannia tube. I have not been able to
devise any good mode of determining the relative amount of friction
of a copper and an iron surface; and, although I believe in copper,
it would not do to act on mere belief. I therefore at present
settle iron, the surface being carefully made smooth. Doubts have
come across me also as to whether with a very long surface the
difference between the smoothness will so much affect the total
resistance. Is not a film of water, after a certain distance,
carried with the body? and, if so, its greater or less roughness,
if not producing currents, is almost unimportant. Would there be
any difference in the resistance of a fine file or a rough one
drawn through tallow, if they both covered themselves with grease?
Is there any similarity? As to size, if we are to go round the
world,[148] I do not think we can do with less than--length, 730;
beam, 85; draught deep, 34; and I assume a nominal horse-power of
engines equal to 1¼ of the sectional area at 30 feet; but, taking
consumption as a better measure, and assuming that every possible
economy is practised, and every refinement introduced that can
produce economy, I shall assume 7½ lbs. per hour per nominal
horse-power, or say 0·08 ton per day per horse-power; and as I
assume the horse-power to be 1¼ sectional area, it makes the
consumption =0·1 ton per day per foot of sectional area. And this
is a very large allowance and ought to ensure a very high speed. In
order to effect the utmost economy, I should work up to 20 lbs.
steam (calling it 16 lbs.), cutting off certainly at ⅓ the
stroke, and adopting every precaution to keep the steam hot and the
condenser cool. The latter depends, I believe, solely upon the
perfect dispersion of the injection water, so that the condensation
of the steam may take place suddenly, otherwise the same amount of
water may condense the steam _in time_, the same amount of heat be
given off, the same quantity of injection water used, and yet the
condenser be always full of steam at a good pressure. It might be
well worth the experiment to try the effect of a large injection at
the moment of the exhaust port being opened; but above all things I
believe the heating of the steam to be important; and for this
purpose I should jacket the steam pipes and cylinders top and
bottom, and heat with high pressure steam, say at 60 lbs.--I have
increased this pressure the more I think of it; 60 lbs. would be
above 300 degrees, and 20 lbs. not quite 260 degrees; therefore
there would be a full 40 degrees of surplus to ensure the
temperature. I have a great tendency to believe in the advantage of
further heating even, which might be done by a Perkins’ arrangement
of hot water; but possibly the new conditions, as regards oiling,
&c., might involve difficulties not desirable to introduce in this
case. In the boilers it will also be necessary to adopt every
refinement which has been found really to answer, although not
always adopted; above all, every means of keeping them clean--scum
pans, and Field’s exchanging apparatus. But what would be even more
effectual would be some easy means of removing a whole bundle of
tubes and replacing them by clean ones; and surely this would not
be difficult, the tubes being large and with plenty of space, so
that a man could pass his arm between. A rather important addition
to boilers would also be a means of blowing off without noise.
Several modes would seem to be possible, but whatever plan is
adopted, it should be one which is completely self-acting, and
perfectly effectual when used suddenly and without any preparation,
and at a moment of confusion and alarm. Blowing through a wire
gauze pipe would probably be as likely a way as any.[149]
The more consideration I give to the subject the more disposed I am
to adopt oscillating engines for both screw and paddles. The
extreme simplicity and small number of parts, and compactness, and
the direct action of every resistance to the force which it is
wanted to resist, seem to leave nothing to be desired, and would
seem to make it a better and more mechanical arrangement of a
cylinder and crank than any other, quite independently of the
object for which it was originally designed, which was simply
‘stumpiness.’
_February 21._--The original line (to Calcutta) seems likely, after
all, as usual with most original ideas, to be the best; at all
events, so good that the vessel must be built to be able to go
there. The dimensions best fitted for this would seem to
be--length, 700 feet; beam, 85 feet; depth of hold, 58 feet; screw,
24 feet; paddle 60 feet. If arranged for Calcutta, we must arrive
there on an even keel, and therefore, to maintain the most equal
level for the paddles, they must be kept well forward, and the
change principally at the stern. Engines indicated horse-power
8,000; steam at 25 lbs.; auxiliary steam at 60 lbs.
The ship to be lighted with gas, to be thoroughly ventilated by
mechanical means, having large air trunks, with small pipes and
valves to each cabin, with the means of warming this air in cold
latitudes and seasons, and cooling it in the more frequent cases of
hot climates. The ship must be steered from the forecastle, whence
a perfect look-out must be kept with fixed telescope, &c., and
speaking pipes and bells to the engine rooms.
_March_ 14.--At a meeting of the Committee, held this evening here,
the several costs and qualities of four different sizes of ships,
of which all the calculations had been made by me, namely:--
No. Length Breadth Mid. Sec. Draught
1 663 79·9 1,646 24
2 634 76·39 1,640 25
3 609 73·5 1,639 26
4 730 87 2,090 28
were discussed, and the No. 1 determined upon as the best under all
the circumstances. I should propose, therefore, to make the
dimensions of No. 1:--length, 680 feet; beam, 81 feet, to be
swelled to 83 feet; extreme draught, 30 feet; mean, 24 feet; daily
consumption, say 200 tons.
This ship can carry her coal to Calcutta, and arrive and leave with
only 21 feet 6 inches draught, having 9 days’ coal and 3,000 tons
cargo; or she could first go to Australia and back, without or with
very little cargo out, and consequently would take out as much
cargo as you might choose to send coal for her to Australia....
These dimensions are worked out in the design No. 5 (April 9,
1853), but they would be better for a slight increase, if the 83
feet were made 85 feet, and the 680 feet were made 700. We should
have an increase in capacity of 83 × 680=56,440 to 85 × 700=59,500,
or 6 per cent. of displacement. This would bring the displacement
at 32 feet draught up to 31,250 tons.
_March_ 22.--Settled the various dimensions of scantlings with S.
Russell to enable him to direct drawings of all details to be got
out.
_April_ 28.--We are now seeking tenders for engines and ship of
the following dimensions:--Length, 680 feet; beam, 83 feet; mean
draught, about 25 feet; screw engine, indicated horse-power 4,000;
nominal horse-power, 1,600; paddle, indicated horse-power, 2,600;
nominal horse-power, 1,000; to work with steam 15 lbs. to 25 lbs.;
speed of screw, 45 to 55 revolutions; paddle, 10 to 12.
Among the details of improvements still to be considered are the
receiving through measures the coal from the bunkers, and running
it on tramways and waggons to the front of the fires, thus at the
same time measuring out accurately the hourly consumption, and
saving labour; but a still more important object, the use of clean
water--that is, using the same water over again--is well worth
considering; and it is well worth the experiment, whether cooling
down the water of condensation to use again is not in fact the
easiest way. With an unlimited supply of cooling water this ought
to be easy.
_August 7._--Memoranda for engines.--Very sensitive governors to be
applied to both engines to prevent running away.
_November 18._--It is curious that the above should be the last
memorandum, as I now open the book to make the same in consequence
of the accident to the ‘Agamemnon.’[150]
There can be no reason why a sensitive governor should not act in
less than one revolution of the crank, and act upon a tumbler which
should shut off instantly the expansion valve. There should be two
such governors, one to each end of the crank shaft, and they should
work direct from a spur wheel from the shaft without any
intermediate shafting, to give elasticity, or to risk breaking.
(Query, hydraulic governors?)
The auxiliary engine and boiler to be at least 20 feet from bottom,
and, better still, above load water line, or so boxed as to be out
of reach of water; so that if the ship grounded and filled, this
engine would remain serviceable for pumping or anything else.
The history of the ‘Great Eastern’ has now been traced up to the date of
the contracts for the construction of the ship and her engines.
The following selections from Mr. Brunel’s memoranda illustrate the
progress of the design during the early months of the year 1854:--
_February 25, 1854._--The details of construction, both of engines
and ship, involve an immense amount of thought and labour. I have
devoted a great deal of time to it already, and yet even the
preliminary details either of engines or ship are far from being
satisfactorily settled. I have no record of the many consultations
hitherto held on the subject, but shall hope to keep one hereafter.
On the 6th inst., some of the drawings of the ship and of parts of
the engines, having been several times revised and altered, being
ready, I spent the greater part of the day at Millwall[151] in
going again into them, and settled some parts, such as the
dimensions, &c., of cranks, and bearings, general form of engine
frame, and some of the general principles of framing and plating of
the ship. Some other consultations have been held, and again to-day
(February 26) I have spent some hours at Millwall.... Discussed the
details of a midship section, the drawings of which were in a
forward state; directed that the cabins should positively be made 6
feet 6 inches each in the clear, and the bulkheads made subordinate
to this; found that it could be done without difficulty, and
without causing any mechanical objections in construction. I am
anxious to have some approximate estimates of weights.
It is evident that large weights may most easily be wasted or saved
by a careless or close consideration of the best application of
iron in every single detail. I found, for instance, an unnecessary
introduction of a filling piece or strip, such as is frequently
used in ship-building to avoid bending to angle irons; made a
slight alteration in the disposition of the plates that rendered
this unnecessary; found that we thus saved 40 tons weight of iron,
or say 1,200_l._ of money in first cost, and 40 tons of cargo
freight--at least 3,000_l._ a year. The principle of construction
of the ship is in fact entirely new, if merely from the rule which
I have laid down, and shall rigidly preserve, that no materials
shall be employed on any part except at the place, and in the
direction, and in the proportion, in which it is required, and can
be usefully employed for the strength of the ship, and none merely
for the purpose of facilitating the framing and first construction.
In the present construction of iron ships the plates are not
proportioned to the strength required at different parts, and
nearly 20 per cent, of the total weight is expended in angle irons
or frames, which may be useful or convenient in the mere putting
together of the whole as a great box, but is almost useless, or
very much misapplied, in affecting the strength of the structure as
a ship.
All this misconstruction I forbid, and the consequence is that
every part has to be considered and designed as if an iron ship had
never before been built; indeed I believe we should get on much
quicker if we had no previous habits and prejudices on the subject.
_March 3._--Mr. Blake [_of the firm of Messrs. James Watt and
Co._], called, and went fully into the general drawings which he
brought. On the necessity of large surfaces he quite concurred with
me. The extent to which such a general principle should be carried
is of course very difficult to determine; my idea is that it has
never yet been approached....
_March 10._--Engaged all the afternoon at Millwall.... Settled and
signed the drawings of crank and piston rods. Went into many
details of ship....
The extracts from Mr. Brunel’s correspondence which follow, have been
selected as containing a definition in his own words of the position he
held as Engineer to the Company by which the great ship was built.
_Letter to the Secretary of the Eastern Steam Navigation Company._
[This letter was written in consequence of a resolution of the
Directors, asking Mr. Brunel to recommend them a resident engineer,
in order that constant supervision might be exercised over the
works, and frequent reports made to the Board.
The Directors rescinded their resolution; but this letter is
inserted as showing, in clear and forcible language, Mr. Brunel’s
view of the nature of his duties and responsibilities, and as
laying down what in his opinion ought to be the relations between
the Directors of a Company and their Engineer.]
August 16, 1854.
...It surely cannot be necessary to remind the Directors that the
very unusual stake which as a professional man I have been willing,
perhaps imprudently, to risk on the success of this project--I mean
stake of professional character, not mere pecuniary risk--must
secure a much greater amount of attention to any step, and
supervision of any detail on my part, than any ordinary
professional engagement would obtain; the heavy responsibility of
having induced more than half of the present Directors of the
Company to join, and the equally heavy responsibility towards the
holders of nearly half of the capital, must ensure on my part an
amount of anxious and constant attention to the whole business of
the Company which is rarely given by a professional man to any one
subject, and, as it seems to me, ought to command a proportionate
degree of confidence, or rather command entire confidence, in me,
if any at all, for in such a case there can hardly be any medium.
The fact is, that I never embarked in any one thing to which I have
so entirely devoted myself, and to which I have devoted so much
time, thought, and labour, on the success of which I have staked so
much reputation, and to which I have so largely committed myself
and those who were disposed to place faith in me; nor was I ever
engaged in a work which from its nature required for its conduct
and success that it should be entrusted so entirely to my
individual management and control....
The Directors have a right to expect, and will ever receive, from
me the fullest information and the most unreserved communication
upon all points as they arise, as from one who feels the
responsibility of being their sole professional adviser in a very
important and serious business, in which we are all embarked, and
all deeply interested; but I cannot act under any supervision, or
form part of any system which recognises any other adviser than
myself, or any other source of information than mine, on any
question connected with the construction or mode of carrying out
practically this great project, on which I have staked my
character; nor could I continue to act if it could be assumed for a
moment that the work required to be looked after by a Director, or
by anybody but myself or those employed directly by me and for me
personally for that purpose.
If any doubt ever arises on these points I must cease to be
responsible, and cease to act.
_Letter to the Secretary of the Eastern Steam Navigation Company._
[In explanation of the following letter it need only be stated that
an elaborate article on the great ship appeared in one of the
London newspapers of November 1854. Mr. Brunel’s name was only once
mentioned throughout the whole of it, and in these words: ‘Mr.
Brunel, the Engineer of the Eastern Steam Navigation Company,
approved of the project, and Mr. Scott Russell undertook to carry
out the design.’]
November 16, 1854.
Since I wrote to you I have taken the trouble to read through the
long article in the----, and am much annoyed by it. I have always
made it a rule, which I have found by some years’ experience a safe
and profitable one, to have nothing to do with newspaper articles;
but then, if on the one hand the works I have been connected with
have rarely been puffed (never by me), they have also been rarely
affected by misstatements; as such notices, when not inserted by
interested parties, are always slight and unauthentic, and drop
without producing any effect. This article in the----, however,
bears rather evidently a stamp of authority, or at least it
professes to give an amount of detail which could only be obtained
from ourselves; and if, as I think is the case, copies of it have
been circulated by us, it may acquire the character of being an
authorized statement; and, as such, I am individually much annoyed
by a great deal that is in it, and by the omission of much that
might with propriety have been introduced.
What is constantly repeated or implied, and remains uncontradicted,
is at last received almost unconsciously as fact even by those who
have the means of knowing it to be incorrect, if they thought about
it; and, although from system I have never interfered with
newspaper statements, it has not been from any affected or real
indifference to public opinion, perhaps it was more from pride than
modesty, and therefore I am by no means indifferent to a statement
which would lead the public, and perhaps by degrees our own
friends, to forget the origin of our present scheme, and to believe
that I, happening at the time to be the consulting Engineer of this
Company, which I was not, and having had no peculiar connection
with previous successful improvements in steam navigation, allowed
them to adopt some plan suggested by others, who I suspect, if even
such were the case, would never appear to share with me the
responsibility if any failure should result. Of this certainly I
have no fear, but at the same time I am desirous of something more
than mere immunity from blame.
I not only read this article once, but I was so struck by the
marked care shown in depreciating those efforts which I had
successfully made in advancing steam navigation, and mainly on the
strength of which no doubt I originally obtained the confidence of
the Directors, which induced them to enter upon our present bold
undertaking, that I read the paper a second time, and for the very
reason that I have for so many years shunned public writings,
namely, to escape misstatements, I feel compelled on the present
occasion to take some steps publicly to correct those erroneous
impressions, which must be created by a document having the
appearance of emanating from ourselves....
The objectionable points that I refer to evidently did not strike
you, and that is a strong proof how easily incorrect impressions
insinuate themselves unawares; but I feel strongly that a judicious
friend would not have failed to do justice to the spirited
merchants of Bristol, who, in spite of the strongest condemnation
of the plan by the highest authorities, and the ridicule of others,
persevered in building and starting the first transatlantic
steamer. The circumstances as regards the ‘Sirius’ are coloured so
as to be quite incorrect; and the same friendly hand would not have
thrown ridicule, and that by a positive false statement, upon that
which he at the same time admits to have been the means of almost
introducing two of the greatest improvements in steam navigation. A
writer wishing success to our enterprise would not have omitted to
mention that I had a claim to public confidence on this occasion,
for the reason that I was at least the principal adviser in those
previously successful attempts.
And lastly, I cannot allow it to be stated, apparently on
authority, while I have the whole heavy responsibility of its
success resting on my shoulders, that I am a mere passive approver
of the project of another, which in fact originated solely with me,
and has been worked out by me at great cost of labour and thought
devoted to it now for not less than three years....
The works had been commenced in the spring of the year 1854, and the
progress of the ship towards completion was eagerly watched, both by
scientific men and by the general public.
The newspapers and periodicals of the day frequently contained
descriptions of the work, and statements of the anticipated performances
of the ship, often very much exaggerated. The writers seem to have been
quite at a loss how to convey to their readers any idea of her size, and
they generally attempted to do so by comparing her dimensions with those
of some of the well-known streets and squares in London.[152]
In the beginning of the year 1855, the longitudinal and transverse
bulkheads, which formed the main framework of the ship, were completed
for nearly 400 feet of the centre portion, and the plating was being
fixed in place.
As the general design was now settled, it was thought that the time had
arrived when it would be desirable for Mr. Brunel to describe at some
length the nature of the undertaking, and the manner in which it was
being carried out.
_Report to the Directors of the Eastern Steam Navigation Company._
[This Report was published at the time and excited much
attention.[153] The paragraphs which describe the arrangements
proposed for launching the ship have been omitted, as they will
more conveniently be inserted in the following chapter.]
February 5, 1855.
* * * * *
Although the simple description of the present state of the works
of the ship and engines, and of what has been done during the last
six months, may be summed up in a few words, I shall, in compliance
with the request of the Directors, embody in this the substance of
the several other reports which I have from time to time made to
the Court of Directors during this half year, and take this
opportunity of laying before the proprietors the fullest
information upon our plans and proceedings. In doing this it may be
difficult to avoid some appearance of repetition of statements
previously made; but I have thought it better, even at the risk of
this, to refer to the objects we have had in view, and explain
fully the nature of the works we have undertaken, and the manner in
which we are carrying them out.
The construction of the vessel is the portion of our work which,
without being actually novel, involved in all its details the
greatest amount of special consideration and contrivance.
The unusual dimensions, the general form and the mode of
construction of all the parts involved by these dimensions, the
necessity of studying each part in detail, so as to obtain, by
judicious mode of construction alone, the greatest amount of
strength with the minimum amount of material; all these
circumstances, and particularly the last, have rendered necessary a
very large, though unseen, amount of labour in the preliminary
plans and stages of the work; and, although I had for nearly two
years before the contracts were entered into, devoted a great deal
of time and thought to the subject, yet of course until the exact
size of the vessel, and the general plans of the Company, had been
finally determined upon none of these matters could be entered into
in detail. Much time has consequently been required to mature and
prepare these plans; and as I have made it a rule from the first
that no part of the work should be commenced until it had been
specially considered and determined upon, and working drawings in
full detail prepared, and, after due deliberation, formally settled
and signed, the work did not make at the onset that display of
progress which might have been made, if less regard had been paid
to establishing a good system which would prevent delays hereafter,
and ensure a more perfect and satisfactory result. I am not
prepared to say that the work is in that state of progress which
will ensure its completion within the period fixed in the contract;
but I am quite certain that if we had proceeded with less system we
should have considerably delayed the final completion.
I shall now refer to a few of the principal peculiarities in the
construction of the ship.
In the preparation of the detailed plans, I have carried out fully
those principles which I originally described as leading features
of the construction.
The whole of the vessel is divided transversely into ten separate
perfectly water-tight compartments by bulkheads carried up to the
upper-deck, and consequently far above the deepest water lines,
even if the ship were water-logged, so far as such a ship could be;
and these are not nominal divisions, but complete substantial
bulkheads, water-tight, and of strength sufficient to bear the
pressure of the water, should a compartment be even filled with
water; so that if the ship were supposed to be cut in two, the
separate portions would float; and no damage, however great, to the
ship’s bottom, in one or even two of these compartments would
endanger the floating of the whole, or even damage the cargo in the
rest of the ship, or above the main-decks of the compartment in
question, and all damageable cargo would be stowed above that deck.
Besides these principal bulkheads there is in each compartment a
second intermediate bulkhead, forming a coal bunker, and carried up
to the main-deck, which can, on an emergency, also be closed.
There are no openings under the deep-water line through the
principal bulkheads, except one continuous gallery or pipe near the
water line, through which the steam pipes pass, and which will be
so constructed as to remain closed, the opening being the
exception, and the closing again being easy, and the height being
such that, under the most improbable circumstances of damage to the
ship, ample time would be afforded to close it leisurely, and to
make it perfectly water-tight. I have also adopted the system, to
be followed rigidly and without exception, of making no openings
whatever--even by pipes and cocks--through the ship’s bottom, or
through the inner skin below the load water line, and I attach much
importance to this system.
In the majority of cases in which steamboats are compelled to put
into port from failure of bilge-pumps and other really trifling
defects, no such serious consequence would have resulted, but from
the difficulty and almost impossibility of remedying at sea any
defects in the numerous pipes and openings now carried through the
ship’s bottom, wherever convenient, and without much regard to the
danger of doing so.
I have found no great difficulty in carrying out this system
completely, and the advantages, both as regards safety and the
facility of remedying defects without delaying the ship on her
voyage, must be obvious.
Independently of the security attained by the perfect division of
the ship into really water-tight compartments of a sufficient
number, so that the entire filling of one or even two of them will
not endanger the buoyancy of the whole, the chances of any such
damage as can cause the filling of one of them are greatly
diminished by the mode adopted in the construction of the ship’s
bottom. The whole of the vessel (except the extreme stem and stern,
the whole buoyancy of which is comparatively unimportant from the
fineness of the lines), up to a height considerably above the
deepest water line, is formed with a double skin, with an
intervening space of about three feet. This arrangement resulted
originally from the system of construction I adopted, in which the
bulkheads, placed at intervals of twenty feet, form the main
transverse frames or ribs of the ship, and in the intermediate
space the material is disposed longitudinally in webs connecting
the two skins, giving to the whole much greater strength with the
same amount of material; but one of the most important results has
been the great increased security attained, as the outer skin may
be torn or rent against a rock without causing the ship to leak.
The space between these two skins is thus divided, by the
longitudinal beams or webs and the principal bulkheads, into some
fifty separate water-tight compartments, any one or more of which
may be allowed to fill without materially affecting the immersion
of the ship.
Besides the main transverse bulkheads, at about 60 feet intervals,
there are two longitudinal bulkheads of iron running fore and aft,
at about 40 feet in width, adding greatly to the strength of the
whole, and forming, with the transverse bulkheads, being all
carried up to the upper deck, fire-proof party walls, cutting up
the whole into so many separate parts, that any danger from fire
may be almost entirely prevented.
The transverse bulkheads being perfect, there being only one
door--and that of iron--in each, at one of the upper decks, all
currents of air or means of communicating fire may be completely
cut off; and with an additional precaution, which I will refer to
afterwards, besides the most ample means of supplying water, I
believe that all possibility of danger from fire may be completely
prevented.
All these principles of construction being kept in view, the
details of construction--that is, the arrangement and due
apportionment of the strength and sizes of all the plates, and the
mode of fastening them--having been determined separately, the
plates have been made at once of the required dimensions, and the
work has proceeded systematically. This system is the most
important, as securing not only good work, but affecting, to a much
greater extent than might at first be supposed, the total weight of
the ship; which, although the terms of the contract protect the
Company against any excess of expenditure beyond a certain fixed
sum, is yet of the greatest importance, as will be easily
understood when I mention the fact that several merely trifling
alterations in the modes of arranging the plates and other details
have caused an economy of 20 to 50 tons each, and that the vessel
may thus be made capable of carrying 200 to 300 tons more of coal,
cargo, or provisions; or iron to the same amount may be usefully
applied to strengthen other parts or effect useful additions.
The details of the engines have all been settled; and the principal
parts, as already stated, are in an advanced state of completion.
In considering the plans of those engines, the largest that have
yet been manufactured, I have endeavoured to ascertain what may be
termed the weak points of the best engines hitherto constructed by
the same or by other makers--those points in which experience has
pointed out deficiencies--and to provide fully against similar
defects in our case.
Before commencing the boilers, I have taken every means in my power
of profiting by the experience of others, and have collected all
the evidence and opinions as to the precise form and proportions
which have been found most efficient; and particularly such as have
been found best suited to the combustion of anthracite coal. A very
great difference is found to exist in the useful and economical
results of boilers, even of good manufacture. Some are noted for
the power of producing rapidly abundance of steam, at the cost of
great consumption of fuel; others have the opposite qualities, and
some combine successfully both those qualities which are desirable.
It might have been supposed that all points of such a simple
subject would have been long since settled, and that no boiler
would be made inferior to the best. Such is not, however, the case;
and although the differences of construction are in themselves
slight, the difference of result is often considerable.
I have taken some pains to satisfy myself on these points, and have
endeavoured to select and to copy the most successful boilers; and
in order to remove all doubts as to their fitness for the use of
anthracite, I have made an experimental boiler, and, after numerous
trials, determined upon the form and dimensions to be adopted.
In the consideration of these details, as indeed on all other
points affecting the success of this undertaking, I have not
hesitated to consult everybody whose opinions I considered
valuable, and to bring the result of their opinions in aid of my
own and the manufacturer’s experience.
I have only to add, that after giving much consideration to the
question of the diameter of the paddle-wheels and screw, I have
determined them sufficiently for fixing the position of the shafts,
and am now engaged in considering the best form and construction of
the propeller itself, and also the construction of the stern-frame
and rudder of the ship.
The position of the paddle-shaft, and the diameter of the paddles,
have been questions of some difficulty. It being necessary to
provide for a considerable variation in the draught of water,
though not proportionably so great as with many existing large
steamers, and to balance well the relative advantages of securing
the highest average speed, at all the various draughts, or the
highest speed at a light draught, and to combine as far as possible
the two, so that the vessel may be as well adapted to perform
comparatively short and very quick passages to ports not affording
a great draught of water, as long voyages, heavily laden, at a
more moderate maximum, but still a large average rate of speed.
Although the full advantage of the great capacity of the vessel for
carrying coal for long voyages would not be felt in a voyage, for
instance, to New York, or in other short voyages, yet,
unquestionably, she would exceed all other vessels in speed and
extent of accommodation; and if it should be found desirable to
make such voyages, your vessels ought to be able to command almost
a monopoly by their superior capabilities, and I have therefore
endeavoured so to place the paddle-shaft, and so to construct the
wheels, that they may be adapted to the convenient application of
the full power of the engine at a light draught of water and at
very high speed.
As regards the screw, the same points have to be considered, and a
choice made amongst the various forms and proportions more or less
successfully adopted at the present time. I have always found the
reports made upon the results of various forms of screws and
propellers, and the performance of different vessels, so little to
be depended upon, even when apparently made in good faith, and the
results obtained from good authority, that I have been long since
compelled to adopt no conclusion, unless from results witnessed by
myself or by persons observing for me. I have for some time past
availed myself of every opportunity that offered of observing and
obtaining something like accurate results upon the various points
affecting immersion of paddles or screw, and I am engaged in
considering those results.
I have referred to the subject of protection from fire; it is one
of considerable importance, and I have some hopes that a process,
which has been recently patented by Lieutenant Jackson, may be
successfully applied to rendering wood uninflammable. Some door
panels have been already experimented upon with results which have
induced me to pursue the experiments, and I am about to try the
comparative inflammability of various qualities of wood, both
prepared and unprepared; and if we can succeed in preventing the
wood producing a flame, and thus communicating the fire; with the
numerous metallic subdivisions we shall have in the ship, the
spreading of fire, even from cargo or furniture, would become
impossible. I am also engaged in determining the character and
extent of mast and sail to be carried, as provision must now be
made in the construction of the ship for receiving the masts.
The Directors are aware that I have been in communication with
Professor Airy as to the instruments which may be used in such a
ship, to ensure more accurate and frequent observations, and as to
the nature of these observations; an enquiry into which he has
entered with that liberality and desire to assist all improvements,
in navigation especially, for which he is so well known. Several
new instruments are now making for trials.
Sir W. Snow Harris has promised to turn his attention to the
subject of the lightning conductors; and as soon as the iron work
is a little more advanced, and while the form and position of all
the principal masses are visible, the subject of local attraction
and the adjustment of the compasses will be considered by those
most competent to advise; and I am not without hope that the means
of correction may be rendered much more certain and perfect than
usual. I mention these, as some of the numerous points which
require and are receiving attention.
In the last paragraph but one of this report Mr. Brunel mentions that he
proposed to adopt a system for obtaining continuous observations in
order to determine the position of the ship.[154]
His first letter to the Astronomer Royal, which is dated as early as
October 1852, explains the object with which he began his
investigations:--
October 5, 1852.
You may possibly have heard of a project in which I am engaged, of
building some _very large_ steamboats.... Among the several
requirements, which it appears to me are involved in such a large
project, is one in which I hope for your advice and assistance, and
I trust you will consider the subject worthy of your attention. In
such a voyage, where so much depends upon perfect navigation, and
with such a capital at stake, no means can be too perfect and no
expense or trouble must be spared to ensure the constant
determination, with the greatest attainable accuracy, of the ship’s
position and course. The determination of her speed, the effect of
winds and currents, and the variation of her compasses, together
with meteorological observations, are all involved in this; and I
propose to have an observatory and establishment of observers,
whose duty it will be to be constantly engaged, day and night, at
any moment when anything can be visible in the heavens, in taking
such observations as will determine more or less accurately,
according to the nature of the observations that the state of the
weather or other circumstances may admit of, the several points to
be ascertained. Now, the questions to be determined are, what is
the nature of the various observations that can best be made under
all the different, and the favourable and unfavourable
circumstances that may daily arise? what the instruments required,
and what the character and extent of the staff of observers
required; and even whether any, and if any what, new tables might
be useful for such a purpose? The primary object being to be
_constantly_ determining either correctly or approximately the
ship’s true position, and in like manner _constantly_ checking the
compasses and giving her true course. I will not unnecessarily
expose my ignorance in such matters by stating what I have assumed
to be practicable. I will only remind you that experience proves
that in a vessel of such size there will be great steadiness of
motion, and therefore unusual facilities for accurate observation.
Mr. Airy entered very warmly into the subject, as did also Professor
Piazzi Smyth, the Astronomer Royal for Scotland; and a long and
interesting correspondence passed between them and Mr. Brunel.
Experiments were conducted, principally with the view of obtaining a
stand for astronomical instruments by means of the contrivance known as
the gyroscope, the principle of which had been already adopted by Mr.
Brunel in a level designed by him in 1829.
In connection with the observers’ department, Mr. Brunel paid much
attention to designs of sounding apparatus and means for accurately
measuring the speed of the ship. He also intended to have a stream of
surface water constantly pumped up through the observers’ cabin, which
should, by its change of temperature, immediately indicate the presence
of icebergs, instead of the plan of an occasional bucketful being hauled
up on to the deck according to the humour of the officer of the watch.
Mr. Brunel made a very curious contrivance for enabling the man on the
look-out to keep his eyes open in a gale of wind. This consisted of two
sets of vertical plates of tin placed one behind another, diverging from
the direction of the wind, with a clear wide passage between the two
sets of plates. The wind, entering at the end of the apparatus, became
separated by the first two inclined plates, and the residue that passed
on in the direct line was again subdivided, so that at the end of the
last set of plates there was no rush of air between them, and a man
looking through the aperture, with his face to the wind, was in a
perfect calm. This was a useful arrangement, the look-out man’s eyes
being as well protected as though behind a glass. A glass would not
answer the purpose, as it would become obscured with spray.
The unfortunate circumstances which attended the completion of the ship
prevented the introduction of these and many other arrangements which
Mr. Brunel had originally proposed.[155]
In November 1855, the Directors proceeded to appoint a commander to the
ship; and their choice fell upon Mr. William Harrison, one of the most
distinguished of the captains of the Cunard Company’s steamers.
This appointment gave Mr. Brunel great satisfaction; he found in Captain
Harrison a warm and faithful friend, and an able adviser on all matters
connected with the completion and equipment of the ship.[156]
Before they came to a decision, the Directors asked Mr. Brunel to
communicate to them his views on the considerations which ought to
influence them in their choice.
The memorandum he drew up on the management of the great ship, and a
letter on the duties of the chief engineer, are inserted at length, as
forming a complete record of the principles which, in his opinion,
should be followed ‘in the use of this new machine,’ while employed on
the voyages which she was specially designed to make.
_Memorandum on the Management of the Great Ship._
October, 1855.
The question of the principles to be followed in the use of this
new machine, for such it must be considered, and the character and
the qualifications of the man to whom it is to be entrusted, and
the points to which his attention must be particularly devoted,
have long been subjects of deep and serious consideration with
me.[157]
And the difficulties are complicated by the consideration that
public opinion, and those established and universally received
opinions which, being the result of experience, cannot be called
prejudices, have to be considered, and must be yielded to to a
great extent, even when somewhat opposed to sound reasoning, or to
conclusions deliberately formed upon a due consideration of the
novel circumstances under which we have to act; but, while
conceding much to past experience, and to preconceived opinions,
the real requirements of the case must have the first
consideration.
Thus, as it is a ship that we have to navigate, public opinion, if
nothing else, requires that we should have a sailor of undoubted
experience and skill to command her; but although seamanship may be
one of the essential conditions or qualifications for the
commander, I think we shall find, upon examination, that the work
we have to do, and the duties to be performed, and the
qualifications we consequently require in the man who is to conduct
this work, are so peculiar that mere seamanship, in the ordinary
sense of the term, if it were to be solely relied upon, would be
even a disadvantage rather than otherwise, and that we require much
that is not necessarily found in the most perfect specimen of a
seaman, and much that is far more difficult to find than the
ordinary qualifications.
I wish particularly to impress this upon you: the subject has
occupied long, frequent, and serious deliberations. I have come to
the conclusion which you will no doubt readily acquiesce in, that
our first practical mechanical success, upon which so much of our
financial success hangs (although others might reap the benefit
even of our failure in the first instance), will depend mainly upon
the skilful management in our earliest voyages of the machine we
are about to set afloat; but I have also come to the conclusion,
the correctness of which may not be so immediately apparent to you,
that this machine, though nominally a ship, not only admits of, but
requires, a totally different management from that which may have
successfully navigated ordinary ships, and that most of the habits,
feelings, and sensations, amounting to instinct, possessed by a
good sailor, and the peculiar power of skilful adaptation of
expedients to emergencies, which constitute the merits of a
first-rate sailor, have to be put aside for a time rather than
applied in the first instance to make a successful commander of the
vessel.
In navigating a small vessel, a man has to study the appearance of
the weather, the direction of the wind, and that of the seas; to
consider the probabilities of change; to vary his course more or
less with reference to any of these causes, and according not only
to the then state of all these operating causes, but also with
reference to the probabilities of change; and with their
consideration his mind is principally occupied, and it is in the
exercise of judgment and foresight in these points that he shows
his skill.
Steam navigation, and the gradual increase in the size of vessels,
have no doubt materially modified this, but much still remains to
occupy the mind of the commander of a steamer, with which not only
we shall have nothing to do, but too much attention to which, from
previous habits, would divert his attention from that which, under
the different circumstances, will become much more important.
In the same manner, in manœuvring such a vessel in harbour, the
ordinary modes would be totally inapplicable; whereas, by entirely
discarding all previous practices, and keeping in his mind and
making use of the peculiar powers which are at command in this
vessel, and judiciously attending to the immense effect of the _vis
inertiæ_, or momentum of such a mass, so far beyond that of
anything now afloat that it becomes a totally _new_ influence, this
machine may be managed by a skilful man with a facility which is
not attainable with small craft; while such a mass would be
destruction to itself or to anything that comes in contact with it,
if treated at all in the same manner as even the largest steamers
are now handled.
Another peculiarity to be attended to in the management of this
mighty mass is that by no possibility must she be allowed to touch
the ground.
Our ship will be found, I believe, if tried, to possess unusual
strength: no combination of circumstances within the range of
ordinary probabilities can cause such damage to her as to sink her,
even if she were to be run on sharp rocks with deep water around;
and I believe she might remain for months aground, exposed to the
heaviest seas without serious damage. The lives of the passengers,
and even the cargo generally, will be safe, almost perfectly safe,
and so far she will be very different from and very superior to any
vessel now afloat; but there will also be another great difference,
although she may remain safely aground, she will probably remain so
for a long time.
If she were to ground at high water or where there is a little
tide, and when she happens to be rather light of coal, and should
take in any water so as to deepen her, no ordinary appliances in
the power of the crew will get her off, or, at all events, not
without great loss of time, and at very heavy sacrifices. Such an
event in the first year of her career would probably ruin our
Company, as the grounding of the ‘Great Britain’ did the Great
Western Steam-Ship Company, although it proved the good qualities
of that ship, and thus advanced iron ship-building. A sailor will
no doubt receive with disgust and as an insult the suggestion of
the possibility of his running his ship ashore. We cannot afford,
however, to rest contented with this expression of feeling, natural
and praiseworthy as it may be: our circumstances are totally
different; and that which is considered certainly as a serious
evil, but still only an evil more or less serious, would be to us
fatal; it is no longer a question of degree of injury--it is death.
I have had some costly experience; I have had to do with many
steamers--several remarkable for their size and their value,
according to the ideas of the time, and two of them each in their
day considered Leviathans, more wondered at than even ours, and
exciting much more anxiety on the part of their promoters, and
there was as much care taken in the selection of commanders as I
ask you to take now; nevertheless both of these, to the ruin of the
Company in one case, and almost every other steamer I have had
anything to do with, has not merely touched, but been aground. Not
a season hardly passes without a case of even a Queen’s ship going
ashore, although navigated by men educated for the purpose, with
the advantage of every appliance hitherto thought necessary and
sufficient, and with fearful responsibility attached to them. All
these are published cases known to the world; and if the log books
of all the steamers were searched, I believe the result would be a
list in which the ships that had not been aground would form the
exceptions, and, in the majority of cases, the blunder is so gross,
that the most far-fetched excuses of errors of compass and unknown
currents, although in well-known channels, are obliged to be
invented.
The real explanation is a simple one. Ships are navigated with far
too reckless a confidence in the mere personal instinct and skill
of those in command, and in their ability to get out of a scrape in
time. Methodical systems and mechanical means of ensuring accuracy
are far too much neglected, or rather have not kept pace at all
with the great improvements in speed and the power of locomotion
which science has introduced, whether in the construction of steam
vessels or even of sailing ships, and which the advance of the day
now calls for. There are no means at present used of taking
soundings worth having while a ship is going fast through the
water, or in time to be of any use if the soundings shoal rapidly;
the trouble is so great and the operation so slow that it is not
resorted to sufficiently often. The steering by compass is so rough
and so coarse, that no real accuracy is attained. Good observations
to determine position are taken at too long intervals of distance
run, and consequently are subject to be interrupted for too long a
period by what is called and supposed to be continual bad weather;
although it would rarely happen, if persons were continually on the
watch, who had nothing else to do or to think of, that twenty-four
hours would pass without some glimpses of a star or of the sun.
Thus with a speed of ten or fifteen knots, and cloudy weather, and,
above all, with that unfortunate confidence of seamen to which I
have referred, there is never any certainty just at the time when
it is really required. No doubt, skilful seamen do generally arrive
at an astonishing approximation in their estimates, and the results
on the average are most successful, and remarkable proofs of the
skill brought into action. But the instrumental means of attaining
accuracy are lamentably in rear of the improvements that have been
made in the means of locomotion, and have not at all kept pace with
the vast increase of capital embarked in each individual case.
All these deficiencies are, however, easily remedied; the means do
exist, or can be devised, and might be applied if we insisted on
their application. We have seen numerous instances where the
difficulties are admitted and grappled with systematically, and
with what patience and skill a fleet has been piloted up unknown
rivers full of shoals in China, and through intricate channels with
covered rocks in the Baltic. In our case, the object to be attained
is a vital one to us; and what I most dread is the confidence of
our commander resulting from his previous experience preventing his
appreciating the peculiarities of the case, and applying that
greatly increased amount of method and system which is essential to
change that, which is now rendered only highly probable by the
skill of man, into mechanical certainty. The man who takes charge
of such a machine, in which is embarked so large a capital, must
have a mind capable of setting aside, without forgetting, all his
previous experience and habits, and must be prepared to commence as
an observer of new facts, and seize rapidly the results. A man of
sense and observation, with a good mechanical head, and with
decision and courage, would succeed without much previous nautical
knowledge; but, unquestionably, a man familiar with all that is
going on around would be much more competent, provided he does not
allow his habits derived from former experience to induce him to
neglect any of the new means of information in his power, to all
which his former knowledge should be made subservient.
If much has to be unlearnt, or rather carefully set aside for the
time, as generally inapplicable in its present shape, there is also
much to be learnt in the navigation of such a vessel; and one of
the most essential qualifications of the commander would be a
belief in his want of experience, and a readiness to see the
novelty of his position, and a cautious and sound but quick
perception of the new and powerful influences and _new_ effects of
those same causes with which he may have been familiar under very
different circumstances.
The great mass and size of this vessel must necessarily render it
so much less affected by the ordinary disturbing causes of wind and
sea, that, practically, little attention ought to be paid to these,
at least not as expecting the ordinary results; but other effects
may be produced which must be carefully studied and learnt in the
early voyages, so that they may be met and counteracted as they
have been by experienced men under the present system. Thus, as an
example of this class of effects to which I would refer, there is
reason to believe that this vessel, although apparently unaffected
by a wind on the beam, or a cross sea, which would be very
noticeable even with the largest of the present steamers, would
nevertheless have a steady and rather strong tendency to come up to
the wind. A certain direction of a cross sea is not unlikely to
produce a contrary effect. It is quite possible also that the
apparent lee-way, or the deviation of the axis (or keel) of the
ship from the line of the course, will be greater with the wind on
the beam than with smaller vessels, although the actual drift or
lee-way may be less; and all these effects will result from her
great length (unless counteracted by causes I do not now foresee),
and will probably be totally different in degree from any similar
effects now felt. These effects must be carefully studied, and with
a mind prepared to consider them as new, for they will be new and
distinct from anything now experienced. In the same manner, and to
a much greater degree, the effects of the speed which we must hope
to attain will upset all the usual methods of determining
accurately the position and the course of the vessel, and still
more the precautions to be taken in approaching land. A 24 hours’
run, at 20 miles per hour, without a good observation, and with a
possible error of estimate, or a doubt, at all events, of the exact
effect of the set of currents, or of the speed of the ship through
the water, or of the precise amount of lee-way, may easily make an
error of 20 or 30 miles in position at the end of the day’s run.
On the other hand, by almost abandoning the present modes, and
adopting measures which I shall point out presently, adapted to the
new circumstances, a much greater degree of certainty and accuracy
may be attained than is now even sought for. I have had the best
advice on these points, both astronomical and nautical: the
Astronomer Royal, Mr. Airy, who both as a man of science and a
practical man, and by his official position, is the first authority
on such matters, and Professor Smyth, of the Edinburgh Observatory,
Captain Beecher of the Admiralty, and several other scientific
naval men, have assisted me; and, under their advice, instruments
are being constructed, and a system devised, which will admit of
continuous observations being made with great accuracy at all times
of the day, and particularly at night, and by means of which also a
continuous correction of the ship’s compasses with the most minute
accuracy can be kept up, and her position be ascertained with
almost the same accuracy as a point on land; and I have their
authority for saying that such improved means are desirable, and
are attainable.
The importance and advantage of continuous observation throughout
the twenty-four hours, whenever a glimpse can be obtained of any
object which will answer the purpose, and even when the horizon is
invisible, may not at first be evident, but it cannot be
over-estimated. An exact knowledge of the ship’s movements will be
soon acquired that would almost replace observation, and the
average of numerous observations secures an accuracy which cannot
be approached by any other method.
By a careful and continuous comparison of the exact distances run,
with accurate records of the speed of the engine and of the ship
through the water, registered by good instruments (the performance
of which has been tested, and which are being made), and having
proper reference to the varying draught of water of the vessel, the
most precise measure of the speed of the vessel through the water
can be learnt; and by careful observation of the force and
direction of the wind, the effect of any given wind, and an
accurate measure of her drift or lee-way, may be obtained; and
then, by adhering strictly, without regard to wind or weather, to a
course previously laid down on good charts, having upon them the
sets of currents, as already observed, the true position of the
ship may be determined at any moment, and there need never be the
slightest hesitation, or any time or distance lost by doubts.
In addition to the instruments above named, I hope to be able to
provide the means of sounding at moderate depths while the ship is
going her full speed.
Having the means, then, of determining the ship’s course and
position with much greater accuracy than is now practised, we must
seek to make that course, or the distance to be run, the shortest
possible, that is to say, the course which will occupy the least
time.
The exact course to be taken by such a vessel must be determined
upon and laid down upon the charts after a due consideration of all
the circumstances which can possibly affect the time occupied in
the voyage between any two points, and particularly by examining
and considering well all the information which scientific observers
have collected and recorded as to the currents, probabilities of
fogs, or of ice, and other impediments, the chances of meeting
vessels, which must be avoided as much as possible, the average
direction of prevailing winds, varying such course, perhaps, in
certain latitudes with the season of the year, but certainly not
with the temporary direction or force of the winds or state of
weather at the moment; for the speed which we shall attain renders
these causes of secondary consideration, and would interfere with
all ordinary calculations derived from present experience of the
probable state of the wind in the new position which the ship would
attain after a few hours’ run. The business of the commander would
be, therefore, to adhere rigidly to the exact course previously
deliberately determined upon, and not to be tempted to deviate
except slightly, and even then only according to rules which he
shall have previously laid down for himself.
The importance of adhering strictly to this rule cannot be
over-estimated. The period occupied in a voyage will be materially
influenced by the exact course followed, and as such course must
be determined upon only by a calm and somewhat laborious study of
documents, it cannot be safely determined upon except in the
closet, that is, _before the voyage_, and uninfluenced by the
excitement of hopes or by disappointments caused by difficulties.
The safety of the ship and of the enterprise may also mainly depend
upon the rigid adherence to this rule.
With the means at his disposal for checking that course, and with
the method and regularity involved by a rigid adherence to it, and
a correction at once of any departure from it, a degree of
certainty will be attained as to the ship’s position which will
almost preclude the possibility of an accident, and which I
consider practically invaluable as affecting the safety of our
vessel. This rigid adherence to an exactly prescribed course will
prevent any risk of that which is the cause of the greater number
of losses. No inducement of fine weather, or a happy state of mind
and body of the captain, or a desire to save time, or to show the
beauties of a coast, or any other temporary cause, will lead to a
nearer approach to dangerous points than had been previously
determined upon as safe. The shortest and best route, the safest
from all dangers, and giving the widest berth to all shores or
shoals, having been laid down, must be kept to against all
temptations.
Economy of fuel is another consideration of the highest importance.
The engines are of power sufficient, if fully worked, to consume
considerably more than the cargo provided. Large as may be the
supply which the ship is capable of carrying, it is no more than
that which is calculated as necessary for the voyage intended, with
a moderate allowance for contingencies; and it must be borne in
mind that the ordinary means of making up any deficiencies would be
totally inapplicable in our case, since no supply capable of being
drawn in an emergency from other sources would be sufficient.
The precise quantity calculated and provided must be made
sufficient, or the consequences would be serious. The usual
practice, therefore, of going ahead as fast as the engines will
take the ship must be entirely abandoned. Careful observations,
systematically pursued, will show the speed which, under different
states of immersion, can be attained without a disproportionate
expenditure of power, and to this speed the engines must be
limited. A little experience will probably show that, under certain
circumstances of immersion of the ship, or of the state of the sea,
it may be economical to force the screw or the paddle engine, the
one more than the other. This can only be determined by somewhat
delicate and very precise and accurate observations. These must be
made. It is not merely a question of degree, but our whole success
depends upon the application, not of one, but of all these
refinements.
A close study of the relative speed of the ship, as ascertained by
the self-registering logs, and by continuous astronomical
observations, compared with the expenditure of power in the engines
as indicated by the number of revolutions constantly registered,
and the power expended as measured and recorded by the chief
engineer, will be necessary for some time to come, and until indeed
the management of such large ships becomes as much a matter of rule
as it is now, or perhaps ought to be more than it is, with smaller
ones.
As to the use of the sails, while the engines are nevertheless in
full action, it must be entirely a matter of experiment, and an
experiment in which, again, all previous habits and prejudices must
be set aside.
Whether a sail steadies such a ship usefully or not can be, and
must therefore be, positively determined by measurement with proper
instruments, and not by the sensations; and the result upon the
speed of the vessel as compared with the power expended must, in
like manner, be ascertained by positive observations and
measurements. No past experience can do other than mislead. It is
quite possible that the same means which improve the rate of the
present large steamers may be prejudicial to our performance.
The commander must appreciate the necessity of all this study and
attention to what is rather mechanical than nautical, or our voyage
will be a failure. The difference between the peculiar qualities of
such a floating mass as compared with those of the largest steamer
now afloat, is likely to be as great as between the last and a
100-ton cutter; and the most prejudiced believer in the acquired
skill of an old sailor who had learnt to manage the small vessel in
the most perfect and masterly manner, would not expect him to be
able to handle one of the present large steamers, still less to
elicit the best performance out of her. In the same degree the man
who takes the command of our ship must, if he is to succeed, enter
upon his duties with a belief that he has nearly all to learn, at
the same time that this feeling is perfectly consistent with a
proper confidence in his own powers to master the new
circumstances, and to succeed with this as he may have done with
other vessels.
Finally, the commander’s attention must be devoted exclusively to
the general management of the whole system under his control, and
his attention must not be diverted by frivolous pursuits and
unimportant occupations. I believe that even in the present large
steamers much advantage would result from relieving the captain
from all care of the passengers and cargo; but in our case, where
we may have to provide for thousands instead of hundreds, and
arranged in different classes, and living in completely separate
saloons and compartments, the present system of a captain dining at
the table and associating with the passengers would be
impracticable, even if it were desirable. But for much more
important reasons, and on general grounds, I think that while the
commander is of course supreme over every department, he should not
be embarrassed by undertaking any one, still less should he have
his mind occupied with the troublesome and frivolous concerns of a
vast hotel, nor should he be hampered by the necessity of attending
to the hours and the forms of a large society. Moreover, I consider
it essential that he should by his presence and control keep up the
position and the sense of responsibility of the chief officers
under him, by living and messing with them; the commander and those
acting immediately under him must occupy a more dignified position
than they now do.
The result of all these general views is, that the command of this
ship must be considered to consist mainly in the superintending and
keeping up in a high state of order the perfect working of a highly
methodical pre-arranged system, by means of which the ship is to be
made to go like a piece of very accurate machinery, precisely in
the course which has been pre-arranged, and precisely at the speed,
and with the consumption of power, which has been ascertained to be
the highest attainable with the requisite economy; and there must
be a proper establishment of assistants, competent to control each
department of this system. As regards the constitution of this
establishment, I consider the commander should have a staff of
chief officers or captains. I believe three will be necessary, with
a fourth performing general duties and ready to take the place of
any one of the three; that one of them should always be in command
of the ship (under the commander); that, besides these chief
officers, there should be a master, corresponding to a master in a
Queen’s ship, who would have assistants and calculators or clerks,
whose duties would be to keep the ship’s reckoning, to keep up
perfect and continuous observations, to calculate with precision
and set from hour to hour the exact course by compass which has to
be followed, to keep in the course determined upon by the captain,
to keep a series of accurate observations and records of all
matters that can affect the ship’s movements--duties involving an
amount of science and practical astronomical and mathematical
knowledge which requires a superior education, and which is found
only in this class of men. The duty of the master would be
therefore to supply the science necessary for the conduct of the
ship, and to be the commander’s cyclopædia and book of reference,
to be able at any moment to report to the commander the exact
position of the ship and her course, and the variation of her
compasses, and take the soundings, if any, to note the fact of a
change in the temperature of the water, indicating approach of ice,
and any other symptom or fact which can affect the ship’s
movements--all which should be determined by continuous
observations methodically and mechanically made, and not be
dependent upon the chance of the commander’s anxiety or greater or
less forethought. The chief engineer should also be a superior man,
selected more for his general qualifications as a good director of
men and machinery, than as a mere marine engineer. These should
form a staff, and be of a standing to live and mess with the
commander; so that each department should thus be furnished with a
chief competent for the special duties of his department, and
reporting to and acting under the general control of the commander.
That the principles thus laid down as to following exactly a
prescribed and predetermined course, and as to regulating exactly
the consumption of power and consequently of fuel, and the keeping
up a system of what may be termed scientific observation for the
purpose of ensuring this regularity, I submit should be rigidly
enforced; and the commander should be required to adopt these
principles as the guide of his conduct, and to use the measures
that are placed at his disposal for working this machine in the
manner and with the precision pointed out.
_Letter on the Duties of the Chief Engineer._
March 19, 1857.
The duties which I apprehend will devolve upon the chief engineer
of our ship will be, firstly, the supreme direction and management
of both the principal engines, and all the auxiliary engines and
machinery worked by them in the ship; and as the construction of
such a ship, and of many of its adjuncts, such as the iron masts
and yards, steering apparatus, and other parts, are strictly of an
engineering character, and such as in the event of repairs,
particularly at sea or in foreign ports, would require a mechanical
engineer rather than a shipwright, I think it must be made part of
your duty, as the most competent officer, to make yourself
thoroughly acquainted with the construction of the ship and all its
parts, and all mechanism within it, so as to be prepared to take
such share of responsibility as to the state of the structure of
the ship as it may be found desirable to throw upon you as chief
engineer, and at all events to be prepared to be the captain’s
chief authority and responsible adviser on all matters of
mechanical engineering.
The principal duty, however, will of course be the management of
the engines, including the care of the paddle, screw, and other
machinery immediately connected with the engines, or worked by
them; and as the success of the ship as a steamboat will depend
entirely upon the amount of power developed by the engines, in
proportion to the fuel consumed, there is no limit to the degree of
attention, of judgment, and of skill, that not only may be usefully
applied, but that must be applied to ensure success.
I have no wish to alarm you as to the amount of work or
responsibility that will devolve upon you; my object is rather to
show you the opportunity afforded of displaying judgment, skill,
and assiduous attention, and thus, as I hope, to excite your
ambition, when I seek to draw your attention very strongly to the
peculiarities of this case.
In ordinary steam navigation, whatever perfection has as yet been
sought for or attained, the business of the engineer has been
mainly to keep the engines in perfect order, and to develope the
greatest amount of power possible, and, secondly, to effect as
great economy as possible in the consumption of fuel; but the
latter has been merely a question of economy in a pecuniary point
of view, and not of necessity, and has been entirely secondary to
the first condition, so much so that the most successful ships have
not been by any means the most economical, on the contrary, they
have been rather extravagant consumers.
In the present case, the circumstances are totally different, and
it will be essential that you should change altogether your
accustomed views on this subject.
This ship is built to go round the world with a defined and limited
amount of fuel, which you have no power to exceed, or rather, if
you exceed it, at any part of the voyage, the whole is a failure.
The circumstances are therefore reversed, with this additional
condition, that there is no medium or partial success. In the
ordinary cases you have a limited power of engine and an excess of
fuel, in which it is desirable but not essential that you should
effect economy; in the present case you have a limited and defined
quantity of fuel to consume, with an excess of engine power, and
the art will be to obtain the largest total amount of power from
this fuel, expending it progressively, and in such a manner as to
reach a given point. To effect this, and obtain the best possible
results, will require of course that the engines should be kept in
the best possible order; but this, although a preliminary
condition, is an ordinary one, requiring no peculiar duties or
exercise of judgment, and must be assumed, as on all occasions, a
matter of course. The peculiar duties in our case will be the
continuous study in every trifling detail that can effect the
result of the means of obtaining the largest amount of steam from
the defined expenditure of fuel and the use of this steam, so as to
obtain the largest amount of power, and the largest amount of
result.
The mere study of this question must necessarily occupy some time,
and for several voyages it will be a subject of experiment; but the
more rapidly positive information can be obtained, the more prompt
and certain will be our success. To attain success will require a
degree of attention to every minute detail, which it has never yet
been necessary or profitable to devote to this branch.
The continuous weighing out of coals and measure of the products of
each boiler (for which means will be provided), the continual
observation of the extent to which blowing-off is desirable, the
continuous measure by indicator of the performance of the engines
under different pressures and degrees of expansion, so that you can
at all times furnish the captain with the exact performances of the
two engines, and the cost of fuel required to produce given results
in each; so that he may have the means of comparing your
expenditure with the results he obtained in the speed of the ship,
and of learning the relative beneficial effects of employing more
or less the paddle or the screw in different states of weather, or
different immersions of the ship, will be required; and every
method of increasing the performance of each gang of stokers, and
of stimulating their skill and care, and every refinement in each
separate branch of the work, to effect economy of fuel, or rather,
development of power with a given amount of fuel, will be
necessary. We all know full well how, if every effort is
continuously made and every possible care is continuously bestowed
in each department, 4 or 5 per cent. can be saved or gained in many
points, and at many times in the 24 hours, between the drawing of
the coals from the bunkers and the development of power at the
paddle board or the screw blades; and if only 1 per cent. can be
thus gained in a few points, the aggregate will soon amount to 10
per cent., which with us may make the difference between success
and failure. All these things will require judgment, thought and
attention, rather than labour, and, above all, close watching and
method, and good management of men.
Besides these more than ordinary duties during the voyage, the only
peculiarity in the service will be that, with such a costly
machine, the mere interest of money and fixed expenditure upon
which will not be short of 200_l_. a day, and the perfect state of
which is so essential, you will be required to give more attention
to the machinery when in port than is usually required.
I trust that this strong but not exaggerated statement of what
would be expected of the chief engineer, will excite your desire to
undertake the duties, rather than deter you from seeking the post;
and that, if the Directors should accept the offer of your
services, you will enter upon the duties with confidence, though
with a sense of their serious importance. In the event of your
appointment, it will be a necessary condition that you should be
able to commence at once the supervision of the erection of the
engines. This work is already much farther advanced than I should
have wished it to be before the chief engineer had taken charge of
it. I attach great importance to his having that familiar knowledge
of all the parts and their condition, which no study of drawings
can give so well as actual inspection during erection, and I wish
also that he should satisfy himself of the perfect truth of every
adjustment.
It will be seen from the documents which have been printed in this
chapter how ‘deeply and seriously’ Mr. Brunel had considered all the
conditions which were, in his opinion, necessary for the economical
construction, and the successful employment, of the great ship; but it
is hardly possible, by means of extracts from his correspondence, to
convey an adequate impression of the amount of labour he expended--from
the year 1852 to the last days of his life--on the supervision of every
detail of the work. ‘The fact is,’ he said, ‘I never embarked in any one
thing to which I have so entirely devoted myself, and to which I have
devoted so much time, thought, and labour, and on the success of which I
have staked so much reputation.’
Heavy as Mr. Brunel’s duties were in October 1854, when he wrote these
words, a far greater amount of labour was subsequently imposed upon him.
During the year 1855 financial difficulties arose which interfered with
the progress of the ship; and at last, in February 1856, although Mr.
Brunel had done everything in his power to prevent the necessity of such
a step, the works were suspended; and they were not resumed till the end
of May, after which date they were carried on by the Company under the
supervision of the existing staff. It was greatly against Mr. Brunel’s
wishes that this was attempted, except as a temporary measure, as he
considered it impossible for a company to carry on such a work
efficiently and economically.
Notwithstanding all these difficulties, that which seemed at first only
a confused mass of iron assumed by slow degrees the graceful proportions
of a ‘great ship’; and the hull of the vessel was completed by the end
of the summer of 1857, so far as it was desirable to proceed before the
commencement of the launching operations.
CHAPTER XII.
_STEAM NAVIGATION--THE ‘GREAT EASTERN’ STEAM-SHIP. THE LAUNCH._
A.D. 1857--1858. ÆTATIS 52.
REASONS FOR DETERMINATION THAT THE SHIP SHOULD BE LAUNCHED
BROADSIDE TO THE RIVER--AND THAT THE LAUNCH SHOULD BE
SLOW--EXTRACTS FROM MR. BRUNEL’S REPORT OF FEBRUARY 1855--REASONS
FOR THE ADOPTION OF IRON SLIDING-SURFACES--DESCRIPTION OF THE WAYS
AND CRADLES--AND OF THE MOTIVE POWER PROVIDED FOR LAUNCHING THE
SHIP--MEMORANDUM ON PROPOSED ARRANGEMENTS FOR THE LAUNCH (SEPTEMBER
26, 1857)--LETTER TO CAPTAIN HARRISON ON RIVER TACKLE (SEPTEMBER
30, 1857)--LETTER ON THE NATURE OF THE OPERATIONS (OCTOBER 23,
1857)--MEMORANDUM ON GENERAL ARRANGEMENTS AND INTENDED MODE OF
PROCEEDING (OCTOBER 30, 1857)--HISTORY OF THE LAUNCH, NOVEMBER 3,
1857-JANUARY 31, 1858--LETTER TO THE DIRECTORS, NOVEMBER 26,
1857--REPORT AND MEMORANDUM ON THE LAUNCHING OPERATIONS (DECEMBER
17, 1857)--FLOATING THE SHIP--_NOTE A_: EXPERIMENTS AND
OBSERVATIONS ON FRICTION.--_NOTE B_: LETTER TO W. FROUDE, ESQ.
(FEBRUARY 2, 1858).
The mode in which, the great ship was to be launched had necessarily to
be determined before she was commenced. In May 1858, when the contract
for her construction was entered into, the question was left open, and
the contractor was either to launch her, or to build her in a dock ‘if
it be found preferable.’ With Mr. Brunel’s full concurrence, Mr. Russell
determined to build the ship on the river-bank, broadside to the river.
The reasons which led to this determination were fully described by Mr.
Brunel in his report of February 5, 1855. This report has, with the
exception of the parts relating to the launching operations, been
printed above, p. 315. The passages there omitted are as follows:--
One of the first points to be decided was the mode of launching the
vessel, which of course would determine the position in which it
was to be built; and I wish to take this opportunity of explaining
my reason for adopting the plan I have decided upon, which, being
unusual, might be supposed to be unnecessary.
Vessels are generally built above the level of high water, and then
allowed to slide down an inclined plane into the water;
occasionally, as in the case of the ‘Great Britain,’ they are built
in a dry dock, into which the water is afterwards admitted, and
they are floated out.
Both plans were well considered in the present case; but the size
of the dock required, the difficulty of finding a proper site for
such a dock, the depth required for floating a ship with her
engines and boilers, which it was most desirable to introduce while
building the hull, and the depth of channel required to communicate
between such a dock and the deep water of the river, all combined
to render the dock plan a very expensive, and, considering the
nature of the soil in which it would have to be formed, a somewhat
hazardous proceeding. Launching seems to offer the fewest
difficulties and the greatest certainty; but the dimensions of the
vessel required some modifications of the usual modes of
proceeding.
Launching is generally effected by building the ship on an inclined
plane, which experience has determined should be at an inclination
of about 1 in 12, to 1 in 15, the keel of the ship being laid at
that angle, and the head consequently raised above the stern, say
one fifteenth of the whole length of the ship. In the present case
this would have involved raising the fore part of the keel, or the
fore-foot, about 40 feet in the air, and the forecastle would have
been nearly 100 feet from the ground; the whole vessel would have
been on an average 22 feet higher than if built on an even keel.
The inconvenience and cost of building at such a great height above
ground may be easily imagined; but another difficulty presented
itself which almost amounted to an impossibility, and which has
been sensibly felt with the larger vessels hitherto launched, and
will probably, ere long, prevent launching longitudinally vessels
of great length. The angle required for the inclined plane to
ensure the vessel moving by gravity being, say 1 in 14, or even if
diminished by improved construction in ways to 1 in 25, is such
that the end first immersed would become water-borne, or would
require a very great depth of water before the forepart of the ship
would even reach the water’s edge. Vessels of 450 or 500 feet in
length would be difficult to launch in the Thames unless kept as
light as possible; but our ship could not be so launched, the heel
of the sternpost being required to be, as I before said, about 40
feet below the level of the fore-foot. Some mitigation of the
difficulty might be obtained by an improved construction of the
ways; but the great length of ways to be carried out into the river
would, under any circumstances, be a serious difficulty.
These considerations led me to examine into the practicability of
launching or lowering the vessel sideways; and I found that such a
mode would be attended with every advantage, and, so far as I can
see, it involves no countervailing disadvantages. This plan has
been accordingly determined upon, and the vessel is building
parallel to the river, and in such a position as to admit of the
easy construction of an inclined plane at the proper angle down to
low-water mark.
In constructing the foundation of the floor on which the ship is
being built, provision is made at two points to ensure sufficient
strength to bear the whole weight of the ship when completed. At
these two points, when the launching has to be effected, two
cradles will be introduced, and the whole will probably be lowered
down gradually to low-water mark; whence, on the ensuing tide, the
vessel will be floated off. The operation may thus be performed as
slowly as may be found convenient; or, if upon further
consideration more rapid launching should be thought preferable, it
may be adopted.
I have entered at some length into an explanation of all the
reasons which led to the adoption of this plan; as I am anxious
that they should be known, and particularly that it should be well
understood by the proprietors and those interested in our success,
that I am not adopting any novelties; unless, so far as those
modifications of the more usual practices which experience points
out as necessary to meet the peculiarities of a particular case may
be deemed such.
I should add that the necessity, arising from the same causes, of
launching transversely has been felt with long vessels of another
description, namely, pontoons, or floating piers; one of 300 feet
in length, which I have built at Plymouth, was so launched, and
previously to this, one of 400 feet in length by Mr. Fowler on the
Humber.[158]
I hope to be able to arrange that the machinery, which is to be
provided by the contractor, for lowering the vessel down the ways
will be also fitted to form a ‘patent slip’ arrangement for hauling
the ship up for repairs; so that, if it should be found desirable
to do so, such apparatus may be purchased for that purpose, and
fitted up at the port which the ship will frequent. With the view
of facilitating such an operation, or the grounding of the ship on
a gridiron for examination at low water, a sufficient extent of the
floor of the ship is formed perfectly flat, and is so strengthened
as to allow the ship when loaded to be grounded without being
unduly strained.
After it was determined that the ship should be built on the river-bank
instead of in a dock, and parallel to the river instead of at right
angles to it, the next point for consideration was, whether the ship
should be lowered gradually to low-water mark, or whether a free launch
should be attempted.
In a free launch the ship is allowed by the action of the force of
gravity to run down the ways at a considerable velocity. In the case of
the ‘Great Eastern’ there were insurmountable objections to this plan.
Some of them might have been overcome by mechanical appliances; but
these would have introduced complication and additional elements of
risk.
In accordance with the opinion which he had from the first entertained,
Mr. Brunel determined to move the ship slowly down the ways.
* * * * *
Subsequently to his determination to launch slowly, Mr. Brunel decided
to employ sliding-surfaces of iron instead of greased wood.
In ordinary launches the ways are thickly greased, so that there is
between the ways and the cradles a thick stratum of grease, which
renders the friction very small. The conditions, however, do not remain
the same throughout the passage of a ship down the ways; for, when she
has moved some distance, the cradle has been rubbing away and squeezing
out the grease; and therefore the part of the cradle which supports the
middle and bows of the ship meets with increasing resistance from
friction. Another and more serious cause of the destruction of the
lubrication arises from unevenness in the ways.
The result of the action of the friction between the wooden surfaces
after the destruction of the grease is sometimes so great that they
become mutually imbedded, the fibres of the wood being rolled up
together to such an extent that it has been found difficult afterwards
to separate the timbers. The increased friction due to the deterioration
of the sliding-surfaces of grease does not often produce failure in
ordinary ship launches, because the vessel, while still on the fresh
grease, acquires a momentum sufficient to carry it over the lower part
of the ways, notwithstanding the retardation resulting from increased
friction.
It was from a legitimate fear of the development of a retarding force
due to the destruction of the grease, that Mr. Brunel hesitated to
employ wooden sliding-surfaces. The ground was far from solid; and the
use of piles as a foundation for the ways would not have prevented the
possibility of excessive local pressure being brought on parts of the
surfaces. The heat produced by undue pressure at any point under the
great area covered by the cradles would tend to spread and aggravate the
evil; and, had any considerable portion of the sliding-surfaces become
wood-bound, the difficulty would have been far less remediable than in
the case of an ordinary launch, where the cradles and ways are
throughout accessible. But in the case of the ‘Great Eastern’ the space
between the ship and the ways, over a considerable portion of the area
covered by the cradles, was very confined, and it would have been a
most tedious, if not a hopeless, task to get at the injured part so as
to repair it properly.
At the end of the year 1856, when the construction of the ways had to be
commenced, Mr. Brunel acted upon his views as to the dangers attendant
on the use of wooden sliding-surfaces, and adopted iron. By this step,
although there might be some fresh difficulties to be encountered, the
disastrous consequences were avoided which might have followed from
employing wooden surfaces.
* * * * *
Under two places in the length of the ship the ground had been prepared
for the reception of the launching ways. These ways or inclined planes
were two in number, and reached to low-water mark. They were placed at
such positions as best to carry the weight of the ship without straining
her. The ways, as originally designed by Mr. Brunel, were each 80 feet
wide; but, with the desire of spreading the weight of the ship over a
still larger area, he decided to add 20 feet to each side of each way,
thus increasing their breadth to 120 feet. The ship’s head pointed down
the river; 180 feet of the bow projected beyond the forward way, 110
feet were unsupported between the two ways, and 150 feet of the stern
projected beyond the after way. The distance from the starboard side,
the side next to the river, down to low-water mark, was about 240 feet;
and the actual length of the ways, including the portion under the ship,
was about 330 feet.
At the same time that he decided to use iron as the sliding-surface, Mr.
Brunel adopted means for ensuring, as far as possible, the even
distribution of the weight upon the ways. With this object he did not
attempt to make them unyielding, but allowed them to yield slightly, so
that, like a cushion, they might adapt themselves to the under surface
of all parts of the cradles with a sufficient upward pressure. The ways
rested on the river-bank, and piles were used to prevent the earth under
the edges of the ways from swelling out at the sides, and yielding more
than the ground under the middle portion.
The ground having been prepared to the slope of 1 in 12, a layer of
concrete of about two feet in thickness was laid over the area of the
ways. On the concrete were placed timbers running at right angles to the
ship. These timbers, which were imbedded in the concrete, were 1 foot
square, with a space of 2 feet 6 inches between them. Across these
timbers, and parallel to the ship, were placed other timbers, with
intervals of 2 feet between them; and upon these again were laid rails
18 inches apart, parallel to the ways, and at right angles to the ship.
The rails were of the ordinary kind used on the Great Western Railway.
Thus the ways consisted of a network of timber resting on a thin bed of
concrete; and on the top of the timber network were placed the rails
which formed the actual sliding-surface.
* * * * *
The under side of the cradles consisted of iron bars, which were laid
parallel to the ship, and therefore across the rails of the ways. These
bars were each 1 inch thick and 7 inches broad, with an interval of 11
inches between the bars. Upon these bars was fixed 6 inches of hard wood
planking (see fig. 15, _a_), and on this again came the framing of the
cradles. Tapered timbers (_b_) were driven in, so as to fill up the
wedge-shaped space between the hard wood over the bars and the flat
bottom of the ship. On the side next the river, between these timbers
and the rounded part of the under side of the ship, were driven in
separate wedge-shaped pieces (_c_), which were secured to the timbers
below by long bolts, arranged so as to allow the removal of the
wedge-pieces when required. The means of unbolting the wedge-pieces was
an essential provision for floating off the ship, as they had to be
removed before she could move sideways off the cradles. Resting on the
lower timbers of the cradle were stout props (_d_), which pressed
against the ship’s side higher up than the wedge-pieces, and took part
of the weight, and spread it over the outer part of the cradle. There
were similar props (_e_) on the landward side of the cradles.
[Illustration: Fig. 15. Transverse Section of Ship, showing Ways and
Cradles.
_Scale of feet._]
There were 80 rails on each of the ways, and nearly 60 transverse bars
under each cradle; so that there were 9,000 intersections of the bars
and rails. As the ship and the cradles weighed 12,000 tons, each
intersection carried on the average a weight of 1⅓ tons.
* * * * *
After the construction of the ways was settled, the amount of power
required to move the ship down had to be determined.
The motive power was not simply the chains, tackle, presses, &c.; but
there was also the action of gravity. One motive power, then, was not
only available, but was inevitably present; and, as the ways were at an
inclination of 1 in 12, the motive power of gravity upon the weight of
12,000 tons was 1,000 tons. The question to be decided was, whether the
1,000 tons of motive force was sufficient to overcome the friction; and,
if not, then what additional force would be required to do so.
* * * * *
In January 1857, immediately upon the adoption of iron sliding-surfaces,
an experiment was arranged on a considerable scale, in order to form
some idea on this important point. Two rails were laid at an inclination
of 1 in 12, and upon them an experimental cradle was placed, weighing
some 8 tons, and representing a small portion of the actual cradle.
The effect of the friction of iron sliding-surfaces may be summed up
very simply. It appeared that the motive power need not, at most, be
more than would have been given by placing the ways at an inclination of
1 in 8, and that restraining power could not have been safely dispensed
with if the ways had been placed at a greater inclination than 1 in 16;
as it was observed that, contrary to received notions, the friction
became less as the velocity increased, and that, in case any
considerable velocity were attained, a great force would be required
merely to overcome the motive power of gravity down the incline,
independently of that required to destroy the velocity.[159]
The task of getting the ship from the place where she was built to her
moorings in the river divided itself naturally into two parts--the
moving of the ship down the ways, and the floating her from off her
cradles.
This subdivision of the whole undertaking of the launch into two almost
distinct operations is of great importance in considering the manner in
which Mr. Brunel conducted them; especially when it is borne in mind
that one, the moving down the ways, was capable of being, by careful
precautions, rendered almost safe; whereas the other, the floating the
ship off, was dependent on the successful issue of various minor
operations, in the management of which the fallible human element had a
greater share, and where small accidents, though, in their primary
effects, productive only of delay, might cause irretrievable disaster.
* * * * *
In the operation of lowering the ship, there had to be provided both
power to move her and power to check her motion. In floating, but one
force was necessary, namely, that required to pull the ship off if she
got jammed on the cradles.
* * * * *
With a desire to provide for the possibility of an extreme amount of
resistance on the ways, Mr. Brunel designed a complete hydraulic
apparatus, which would have been sufficiently powerful to move the ship
down without interruption or delay. It is much to be regretted that he
did not persist in carrying out his original intention.
In the operation of floating, chains and tackle were the best means of
supplying the tractive force that might be required; and Mr. Brunel
decided to have a very large amount of available power. If the weather
were fine, and the tide at its calculated height, if no part of the
cradles got disarranged, if the calculations as to the ship’s draught of
water were correct--if everything went right, there would be no
necessity for any great hauling power; a few tug-boats would suffice to
take the ship to her moorings. But Mr. Brunel determined that in this
critical operation of floating he would not trust to good fortune, when
the absence of it might produce grave injury. The power which he thought
it desirable to provide in chain purchases for the floating was very
considerable, being equal to a pull of 500 tons.
As it seemed probable that the ship would not require much force to move
her down the ways, it seemed also probable that the river tackle (as the
chains and appliances for hauling the ship off were called) would be
sufficient for both purposes. This being the case, it at the time
appeared right, in the embarrassed state of the Company’s finances, to
dispense with the more powerful and costly apparatus which Mr. Brunel
had proposed for moving the ship down; there being no fatal consequences
to be apprehended from a defect of power.
Influenced by these considerations, Mr. Brunel resolved to trust to the
river tackle alone.
He referred to this decision in a letter to the Secretary of the Company
written during the launch:--
November 26, 1857.
My original intention, the right one, was to fit up properly such
an hydraulic apparatus as should be fitted to move the ship the
whole length of the ways, and to depend upon the whole river tackle
only in the event of her moving very easily, and for getting her
off the ways at the end. From an unwise attempt to economise I
determined to dispense with the immediate costly apparatus for
pushing, and by sufficient power merely to move the ship at
starting or in the event of sticking,[160] and to depend upon the
same river tackle to keep her moving down the ways.
The experiments made with the trial cradle had shown the necessity of
providing a certain amount of restraining force. As will be seen in the
description of the launch, it was only used once, but it must not
therefore be supposed that there was no necessity for providing it.[161]
The arrangement of the checking gear was the same at each of the ways.
Attached to the land side of the cradle, by means of bolts, was a strong
iron framework which held two large horizontal wheels or sheaves. At the
upper end of the ways another sheave was fixed in a strong timber
framing; and opposite the middle of the upper end of the ways was placed
a large windlass or drum.
This drum was a cylinder, about 20 feet long and 6½ feet in diameter, of
solid timbers, strongly bolted together, and secured at each end in a
broad cast-iron disc, 12 feet in diameter.
To a point in the framing was attached one end of a 2⅝-inch chain
cable; this chain was passed round one of the sheaves attached to the
cradle, then round the sheave attached to the upper end of the ways,
then round the second sheave attached to the cradle; and its end was
coiled round the drum. Thus, as one end of the chain was secured, it was
necessary, before the ship could move down the ways, that the drum
should revolve, and slacken the end of the chain coiled round it.
Round the discs of the drum were wrought-iron straps; these, when
tightened by levers, formed brakes by which the revolution of the drum
could be retarded. Gearing was provided with a train of toothed wheels,
so that the drum could be turned round by handles, and the chain wound
on to it.
The following paragraph is from the commencement of a memorandum by Mr.
Brunel on the launching arrangements, written about five weeks before
the launch began:--
September 26, 1857.
It is expected that, with the present construction of the ways, the
friction and the tendency to descend by gravity will be about
balanced; so that when once in motion no very great amount of power
(at least, in proportion to the mass to be moved) will be required
to keep the vessel in motion, or to check it if disposed to move
too quick, or quicker at one end than at the other; still the
forces which may be required either to help it on or to check it,
though relatively small as compared with the mass to be operated
upon, will be very large as compared with forces usually obtained
by the ordinary means of rope or chain purchases, and at the first
start, or after any accidental or intentional stoppage, a still
larger power may be required.
The apparatus which Mr. Brunel prepared for performing the double duty
of moving the ship down the ways and hauling her off the cradles was as
follows:--At each end of the ship was a powerful chain tackle. One end
of a chain cable was secured to a mooring in the river, and it was
passed round a large sheave attached to the ship, then round a sheave
fixed on a barge about 300 feet from the ship, and the end brought on
shore, where it was hauled on by a chain tackle worked by a steam crab.
The sheave attached to the ship at the bow was slung by chains about 80
feet from the stem. The sheave at the stern was fixed on the end of the
screw shaft. These purchases were intended to be good for 80 and 100
tons respectively, and were to be able to follow up the ship quickly if
she moved.
In addition to these purchases, Mr. Brunel desired to have ‘the means of
bringing a considerable strain to bear in the event of the ship sticking
at starting, or at any subsequent time, and particularly at the last;’
and he considered that ‘nothing under 250 or 300 tons would be of any
use for the purpose.’ This power he desired to apply to the centre of
the ship between the two cradles by means of double crabs and treble
purchase blocks on four barges.
One of the double crabs was mounted on each of the four centre barges,
and was placed on a platform, elevated so that the blocks of the chain
tackle could pass underneath it. This tackle was made fast to a chain
attached to the ship; and the mooring chain extending across the river
was hauled on by the tackle.
Each of these four crabs and tackle was to be capable of working up to a
strain of 80 tons. The strain which Mr. Brunel intended to be able to
put on the ship by the river tackle, in the form of a good continuous
pull, was in all 500 tons.
Two hydraulic presses were also provided, one at each of the cradles, to
overcome adhesion in first moving the ship. Each of these presses should
have been able to exert a strain of 300 tons. Therefore, including the
force of gravitation, the power which Mr. Brunel hoped to have to start
the ship was 2,100 tons, or more than one-sixth of the weight to be
moved; and for a continuous steady pull to keep her moving, 1,500 tons,
or one-eighth of the weight.
* * * * *
It was at one time thought possible that the launch might be effected in
October. But it was found that it would be impossible to be ready before
the spring-tides at the beginning of November; and even then, when the
time came, there was considerable hurry, and important matters were, as
will be seen, insufficiently attended to.
The cradles were put together and wedged up under the ship, and every
effort was made at low water to extend the ways as far as possible; so
that, by moving her further down the slope, a greater margin might be
obtained, to allow for any falling off in the expected level of the
tide, or for any miscalculation in the ship’s draught.
In the memorandum already referred to on the launching arrangements Mr.
Brunel instructed Captain Harrison to superintend the moorings for the
river tackle, and to satisfy himself of their sufficiency. A few days
afterwards he wrote to Captain Harrison on the subject:--
September 30, 1857.
I fancy (I may be wrong) that you hardly estimate sufficiently
highly the forces that we may require to get the ship down if she
sticks at all, or to drag the cradle from under her, or to force
her off the cradle at the last. She _may_ move down pretty easily,
and the cradles _may_ possibly not stick; but if she does stick at
all, it is as likely to require a dead pull of 500 tons as not, and
we must not shut our eyes to the real exact amount of strain which
may and will come upon purchases and moorings, &c., if this force
is required and is exerted; but we must provide for it. The several
moorings must really be good for the 80 and 100 tons respectively
mentioned in the memorandum--and we must not rest satisfied with
the feeling that the moorings are stronger than any generally sold
or than common tackle will effect, but must apply purchases that
will produce the strain, and if necessary we must strain them to
it; and our moorings ought to be beyond a doubt.
We are going to move 11,000 tons, a far greater weight than ever
was moved before, and we must not hesitate at providing a clear
pull of 500 tons; but bear in mind that 500 tons clear pull is
something much beyond what one is accustomed to. The power usually
brought to bear with purchases, chain cables, &c., is never
measured, but is very small; and we must take care and not be
misled by comparison with them. 80 tons is a heavy pull, and
nothing under 2 or 2¼ chain will be safe....
These are great strains we have to deal with, but they must be had,
and therefore we must meet them boldly.
Frequent enquiries were now made relative to the time of launching; and
the number of applications which poured in for admission to the yard led
Mr. Brunel to write the following letter to the Directors of the
Company, and it was published by them in the newspapers. In it he not
only removed current misapprehensions as to the nature of the proposed
operations, but he also took the opportunity of pointing out that there
would be no risk to the ship in the mode of launching adopted, and that,
although it might at first be unsuccessful, further power could be
applied, and the ship safely launched.
October 23, 1857.
The difficulty of replying to the numerous enquiries made
respecting the period at which the ship will be launched seems to
render it desirable that some means should be taken of giving the
information generally, that it may be uncertain, up to the end of
next week, whether the ship will be launched on the 3rd proximo or
the 2nd of December, and also of correcting the erroneous
impressions which exist as to the nature of the operation, which
can only lead to the disappointment of those who are erroneously
anticipating a display, on an unusually large scale, of that which
is a beautiful spectacle with ships of ordinary dimensions.
As regards the period of the launch I have, for some time past,
calculated upon being ready by the first tides of next month, and
by the unwearied exertions of those on whose assistance I have
depended, with the advantage of unusually fine weather, the
principal works required are so far advanced that there seems every
prospect of success; but a change in the weather is threatening,
the time remaining is short, and comparatively small causes may
create such delay as to render it more prudent, if not unavoidable,
to postpone the operation until the following available tide,
namely, that of December 2. As no mere desire to launch on the day
supposed to have been fixed will induce me to hurry an operation of
such importance, or to omit the precaution of a careful and
deliberate examination of all the parts of the arrangements after
all the principal works of preparation shall have been completed,
should such postponement prove necessary or be adopted from
prudence, everything having been now prepared, the launch would be
on December 2.
As regards the nature of the operation, it has frequently been
stated, but it seems necessary to repeat it, that the ship will not
be ‘launched,’ in the ordinary sense of the term, but merely
lowered or drawn down to low-water mark, to be thence floated off
by a slow and laborious operation, requiring two and possibly three
tides, and very probably effected partly in the night, and at no
one time offering any particularly interesting spectacle, or even
the excitement of risk; as I am happy to feel that, even assuming
accidents to occur or miscalculations to have been made, rendering
the operation unsuccessful--the ship may stop halfway or not move
at all, more power or other remedies may have to be applied--but no
injury to the ship can result from any failure in the course of
proceeding in this mode of launching.
Throughout October an immense amount of work had to be done, and the
multiplicity of matters to be attended to pressed heavily on Mr. Brunel
and his assistants.
With the check tackle he had reason to be content. The chains, which
were the ship’s cables, had been very carefully made; and, in addition
to the usual tests, pieces had been taken at hazard, and were found to
bear a good breaking-strain.
The river tackle was not so satisfactory. In operations that have to be
conducted afloat unexpected delays arise, and all the work may be
suspended by bad weather, and it is moreover frequently dependent on
tides. In the present case the work to be done was not easy. Heavy chain
cables had to be laid out, and moorings picked up and connected to the
tackles; one work having often to wait for the completion of another.
Mr. Brunel had determined that each purchase should be tested by being
strained to the utmost stress for which it was intended; but, owing to
the delays which had occurred in preparing the river tackle, this was
not done.
* * * * *
A few days before the launch Mr. Brunel addressed the following
memorandum to all who were to take part in the operation:--
_General Arrangements and intended Mode of Proceeding._
October 30, 1857.
It is desirable that all engaged in directing any part of the work
should understand the general course of proceeding which it is
intended to pursue, so far as may be found practicable;
circumstances may modify these pre-arranged plans, and may compel a
total departure from them, but every endeavour will be made to
adhere to them.
GENERAL COURSE OF PROCEEDING.
[Sidenote: To start about noon of Tuesday.]
I propose to commence operations about two hours before high water,
or about noon, and to endeavour to get the ship down as quickly as
I can into the water, and down to within about 36 feet of the
bottom of the ways.
My object in starting at this particular time of tide would be to
get the ship into the water, and waterborne to some extent as soon
as I could.
[Sidenote: Stop short of end of ways.]
I propose to stop short of the end, in order to avoid the necessity
of having to knock away all the shores, and clear the cradle at the
evening tide, when it would be dark, and to float on the morning
tide, when it would be also dark.
I should propose then to stop about 36 feet short of the end.[162]
[Sidenote: _Evening._ Clear away shores of the 20-feet cradles.]
At low water, although dark, I shall endeavour to knock away the
shores of the 20-feet cradles, or as many of them as possible, and
clear all from these cradles except the unbolting of the
filling-pieces.
[Sidenote: Under favourable circumstances clear away also _all_ the
shores on the port side.]
If the operations have proceeded easily, and the ways not sunk
much, I shall also knock away all the long shores on the inshore or
port side of the ship, so as to leave less to do on the following
day.
[Sidenote: Prepare for a further pull at the night’s high water.]
I shall then prepare at leisure to place the barges to get one pull
of 36 feet, or as much more as I can (as I shall not hesitate to
pull the cradles 20 feet off the ways) after high water of that
night.
[Sidenote: Last move at 4 A.M.]
Soon after the high water of that night, and when the water has
fallen sufficiently to prevent any risk of floating, but while the
ship is still waterborne, probably about 4 or half-past 4 A.M., I
shall make the last pull; and although it will be in the dark, yet
having only one pull to make, and plenty of time to prepare, and no
expedition required in the operation, I think it may be easily
done.
[Sidenote: Float on high water, Wednesday afternoon.]
The ship will then be left till low water, when we shall clear away
everything we can from the cradles, and get all ready for floating
at high water on the afternoon of Wednesday.
Provided the mechanical arrangements should prove efficient, the
success of the operation will depend entirely upon the perfect
regularity and absence of all haste or confusion in each stage of
the proceeding and in every department, and to attain this nothing
is more essential than _perfect silence_. I would earnestly
request, therefore, that the most positive orders be given to the
men not to speak a word, and that every endeavour should be made to
prevent a sound being heard, except the simple orders quietly and
deliberately given by those few who will direct.
In a memorandum of ‘Particular Instructions,’ dated the next day,
October 31, there is the following passage:--
_Starting_.--A strain being brought upon all the purchases, and the
holding-back purchase being slack, if the ship does not move, the
two presses will then be worked; if she does not then move, or if,
when moved, she stops and each time requires the presses, the
attempt will be postponed, and more moving power applied for the
next time.
If, after being started by the presses, the river purchases are
found sufficient to move her, the operations will proceed.
In another part of these ‘Instructions’ Mr. Brunel again shows that he
was not, as has sometimes been supposed, under the impression that the
friction would be so small that the only important thing to be thought
of was to check the ship from rushing too fast.
On the contrary, he foresaw the possibility of her not moving at all,
even with the presses, that is to say, with a force of 1,100 tons over
and above the action of gravity. If after moving she stopped, and then
required the presses again to move her, this would show that the
operation could not be properly carried out, and that the work must be
suspended till more motive power was applied. If, again, the river
tackle were sufficient to move her, then the work was to proceed, but
the friction might even then be so great as to render it desirable to
remove all retarding force. He says, in another passage in his
‘Instructions:’--
It is very likely that no checking whatever at the drums will be
found necessary, but that, on the contrary, it will be found
desirable to get rid of any resistance by overhauling the heavy
chains through the sheaves.
The best day on which to begin the launch was Tuesday, November 3, as it
left two or three days of the high full moon spring-tides for the
operations, should they be prolonged.
On Monday, November 2, the chief work remaining to be done was stowing
kentledge or iron ballast on the cradles, to prevent the timbers
floating when the ship should be moved off them. All the appliances were
ready, and, except the river tackle, had been carefully examined. This,
as has been already said, had not been tested.
It was now for Mr. Brunel to consider whether, in consequence of the
river tackle not having been properly tested, he should postpone the
launch till the following month.
It was most important for the Company that the ship should be afloat as
soon as possible; and, as any defects which might exist in the river
tackle would almost certainly declare themselves in the earlier part of
the operation, when nothing worse than delay could be apprehended, Mr.
Brunel, after a careful review of all the circumstances, determined to
attempt the launch.
* * * * *
On the morning of November 3, the work of putting kentledge on to the
cradles was completed by firelight, and the rails were rubbed over with
a mixture of oil and black-lead. All the shores and props which
supported the weight of the ship had been removed, and she was now
resting entirely on the cradles.
Later on in the morning the brakes of the drums were tightened down, and
the dogshores were removed from the ways in front of the cradles. Mr.
Brunel, who had been engaged from an early hour in examining all the
preparations, superintended this operation, and, having satisfied
himself that all was clear and ready, returned to the upper part of the
yard.
By this time it was crowded with people. The Directors, contrary to Mr.
Brunel’s expressed wish, and without informing him of their intention,
had issued a large number of tickets of admission. A few days before,
Mr. Brunel had suggested that four policemen should be obtained,
thinking that all they would have to do would be to contend with
trespassers. The police force actually present were ignorant of the
portions of the yard to be kept clear, and Mr. Brunel had himself to go
and assist in ordering visitors away from the neighbourhood of the path
prepared for the tackle of the stern hauling gear. The crowd soon became
so great that it was almost impossible for the men in charge of the
hauling-engine at the stern to see the signals given from the middle of
the yard, or for those in the middle of the yard to see what was
happening at the stern.
At about half-past 12 o’clock the fastenings of the ship at the bow and
stern were let go, and Mr. Brunel ordered a small amount of slack to be
given off from each drum. This was done by men turning the handles of
the gearing which had been provided for winding the chain on to the
drums. The order was then given to haul on the bow and stern tackle, and
to pump at the hydraulic presses. It is doubtful what amount of strain
was put on by the tackle and the presses, but it was probably not very
great.
Presently a shout from the forward cradle announced that it was moving,
and almost immediately the stern cradle also started with what appeared
to be a considerable speed. The men who had been engaged in turning the
handles of the gearing had remained leaning against them. As soon as the
ship had moved a few inches, she took up all the slack chain. This made
the drum revolve, and the handles of the gearing spun round very
rapidly, striking the men, and throwing them into the air. The men who
were at the brake-handle next to the gearing ran away. Mr. Brunel, who
was standing near the drum when the accident happened, shouted to the
men to hold on to the brakes, and ran to the spot. The men who had
remained at the other brake-handle hauled it down with the tackle. A
great restraining force was thereby brought upon the ship, and her
progress ceased; the forward cradle having moved 3 feet, and the after
cradle 4 feet 3 inches.
Five men were injured. On the death of one of them it was stated at the
inquest, by the foreman of the drum, that, after the slack had been paid
out, he had ordered the men to stand clear. Be this as it may, it cannot
be denied that the handles should not have been used after the securing
chains had been let go; and indeed Mr. Brunel said at the inquest, ‘I
may blame myself, for I did not anticipate that the handles would have
revolved so rapidly.’
After this accident, Mr. Brunel determined to wait till high water
before recommencing the operations. In the meantime the gearing was
removed from both drums.
A more important change was also made in the arrangements. When the ship
moved, the men on the four middle barges became frightened, thinking she
was about to overwhelm them; a rush was made, and one man, jumping into
a small boat, shoved off, leaving the rest to their fate. A report was
at once sent to Mr. Brunel that the men were untrustworthy, and that
they would not remain; and that, as the barges would be of no use
without the men, the chains had better be dropped and the barges
removed. To this Mr. Brunel consented.
It would, however, have been sufficient to take the men off, leaving a
tug-boat and a few steady men to keep the barges out of the way of the
ship; they would then have been available if required. Mr. Brunel, a
short time after he had given the order, ran round the bow with Captain
Harrison to countermand it; but it was too late, as it had been already
acted upon. As events turned out no harm was done, as the centre barges
alone would not have been sufficient to go on with, after the rest of
the tackle failed.
The result of these changes was that when the operations were
recommenced, the only hauling gear was the bow and stern purchases; the
hydraulic presses were also available to start the ship.
At a little after 2 o’clock the signal was given to haul on the bow and
stern tackle, the presses being at the same time pumped up. The brakes
of the drums were slackened, but kept all ready for tightening.
Not long after the strain had been brought on the tackle, several of the
teeth of one of the wheels of the bow steam crab gave way, and the chief
anchor at the stern began to drag, so that no efficient strain could be
obtained. On this being reported, the operations were discontinued; and,
as there was no possibility of getting things ready by the next day, the
launching operations were postponed till December 2, the next full moon
spring-tides.
* * * * *
As soon as this was known the visitors rushed in on the works, crowding
about the cradles and ways; and Mr. Brunel had to postpone those
investigations which he wished to make at once.[163] The whole yard was
thrown into confusion by a struggling mob, and there was nothing to be
done but to see that the ship was properly secured, and to wait till the
following morning.[164]
* * * * *
The next day was devoted to an examination of what had gone wrong, and
to the consideration of what should be altered before another attempt
was made.
At the stern mooring the anchor was bedded into the ground on the
further side of the river.
The difficulty with regard to the four centre barges was got over by
placing the four crabs with their tackles in the yard, on the landward
side of the ship. The four chains attached to the ship, which had before
been hauled on directly from the barges, were now passed round sheaves
on the barges, and brought back under the ship’s bottom to the tackles
in the yard.
The chief alteration, however, was in the arrangement of the hydraulic
presses. On November 3, there were, as has been said, two presses. Two
additional presses were now provided; each of these consisted of two
7-inch cylinders, and was equivalent to a 10-inch press.
With the object of being able to employ the presses continuously during
the descent of the ship, they were arranged to point down the ways at an
inclination of 1 in 12. The four presses were placed one on either side
of the check tackle at the two ways, and were supported by abutments of
timber-work. These abutments each consisted of four rows of piles, one
behind the other at intervals of about 8 feet. The press abutted against
the row of piles nearest to the ship, which were connected by wooden
struts to the piles behind them. Long balks of timber of various lengths
were prepared to transmit the pressure to the cradles.[165]
The four presses might be considered equivalent, at their full power, to
a force of 800 tons; this was so much in excess of the small force that
had moved the ship on November 3, that, even making every allowance for
the advantage of the fresh lubrication in the first instance, it seemed
reasonable to suppose that with this force the ship could be moved down
easily.
* * * * *
As the process of moving the ship with the presses would naturally be a
slow one, Mr. Brunel determined to proceed with the operations as soon
as everything was ready. On November 19 the work was commenced.[166] The
bow tackle was hauled upon first, as the forward cradle was more than a
foot behind the after one, and the men at the forward presses were set
to work. After a short time the timber backing of the presses began to
crack and ‘cry out’; and, without much stress on them, the abutments
were forced back some 3 or 4 inches. The mooring chain of the bow
tackle also gave way, although there was not any excessive strain on it.
On examining the abutments, Mr. Brunel saw the cause of their failure,
and ordered the strain to be taken off. The number of piles was
sufficient, but the way in which the strain was communicated to them did
not enable them to exert the proper amount of resisting power.
This defect was cured by tying the heads of the rearward piles with
bolts to the foremost piles. The ship being secured, each press was
tested to a full strain, and the adequacy of its abutments ascertained.
It was different, however, with the river tackle. The chain which had
parted was an old river mooring-chain of great size. Much delay in
replacing it was caused by dense fogs, which made it almost impossible
to work on the river. Moreover, there seemed a fatality about every
attempt to get a regular trial of any part of the tackle. When, at last,
a trial took place, and a strain was put on, a mooring-chain gave way;
then this had to be fished up from the bottom of the river, and pieced
together, the accident being ascribed to a defective link in the chain.
The trials were, therefore, so few that it was only proved by degrees
that all the regular moorings were worthless; although they had large
chains which ought to have been good for three times the strain put on
them.
* * * * *
The stubbornness of the ship on November 19 gave Mr. Brunel great
anxiety; not from any fear of being unable to apply sufficient power to
move her, but because, on continued consideration of the subject, he
apprehended that a serious difficulty might arise, if there should be a
prolonged delay at a particular part of the ship’s progress.
It has been explained that Mr. Brunel, with a view of obtaining
uniformity of bearing over the surface of the ways, had not attempted to
support them rigidly on piles, but had rested them on the river-bank.
As, however, the foundation of the building slip was comparatively
rigid, he feared lest an unequal subsidence might cause injury to the
ship, if she were stopped for any length of time before she had
completely left the ground on which she was built. He thought that if
the ways sank at this point they would assume a slightly convex form,
and tend to force upwards the flat bottom of the ship. The main part of
the ship’s bottom, between the longitudinal bulkheads, could bend in
slightly under a heavy upward pressure; but this action could not take
place at the transverse bulkheads, as they would not yield without
injury. Mr. Brunel shrank from proceeding with the launch without having
in reserve such an amplitude of power as would prevent the ship’s being
stopped at this critical point. This consideration, together with the
continued failure of the river tackle under such tests as were applied
to it, led him to address the following communication to the
Directors:--
November 26, 1857.
We proved two of the presses yesterday afternoon up to the full
pressure. A third, the largest, was proved partially; it required
some additions, which are nearly completed, and will be in a few
hours. The fourth may, I think, also be relied on to the same
extent, nevertheless, after a careful examination of the effects of
these strains and other circumstances, I have, after a night’s
consideration, come to the conclusion that our means are too
imperfect to justify my moving the ship with them in their present
form. The presses would start the ship, but it is evident that if
required to be used constantly, that is repeatedly, the piles would
become loosened so as to draw and rise; this again might be
remedied by loading, but clumsily, and with other contingencies,
which I will report, combine to render it hazardous to depend upon
them. My original intention, the right one, was to fit up properly
such an hydraulic apparatus as should be fitted to move the ship
the whole length of the ways, and to depend upon the whole river
tackle only in the event of her moving very easily and for getting
her off the ways at the end. From an unwise attempt to economise I
determined to dispense with the immediate costly apparatus for
pushing, and by sufficient power merely to move the ship at
starting or in the event of sticking, and to depend upon the same
river tackle to keep her moving down the ways. The power originally
calculated upon for the river tackle has gradually, step by step,
failed us; the moorings supposed to be sufficient for certain
strains have failed us at one-third of those strains, another has
parted since our last attempt, and, instead of full 350 tons of
power from this source, we cannot now depend upon 200, and this,
added to the inefficiency of the pushing power, would risk the
sticking of the ship, which might occur exactly at a point which
would involve serious difficulty to remedy. I am assuming a
combination of adverse circumstances, perhaps not likely to occur,
but quite possible; and the conclusion I am compelled to come to is
that our apparatus is too defective, and that the original plan of
a proper and sufficient hydraulic apparatus, arranged in a complete
well-constructed mechanical manner, to push the ship continuously
down the ways, ought to have been followed out, and is now the only
mode of doing the work safely, that is, without the risk of being
involved in a difficulty much greater and more costly.
I have only to add that bad as this report of our condition is, it
is at any rate the worst that can be made of it, that nothing
whatever has occurred to show that any new difficulty has arisen or
anything whatever to create any new difficulty. We could move the
ship now if it were wise to do so, but with great doubts whether
our pushing apparatus in its present form, imperfect and
unmechanical, would continue effective if repeatedly used, and the
certainty that our river tackle is far inferior to what is
required, and also of doubtful and more than doubtful permanency
for repeated strains, it would not be right to commence....
Mr. Brunel at the same time determined to obtain, on a large scale, a
measure of the deflection that might be expected from the weight of the
ship coming on the ways. More than 100 tons of kentledge was piled on a
portion of the ways 10 feet square, in such a manner as to give a
pressure thereon of about double that which would be produced by the
weight of the ship.
It was necessary that this test should not be tried on too small a
scale, as a weight resting on an isolated patch would receive support
from the surrounding ground, which it could not of course do if that
ground was equally loaded. The ways sunk so little under the test as
completely to reassure Mr. Brunel, and to show that no serious evil need
be contemplated in the passage of the ship from off the place where she
was built on to the newly made ways, even though she might be again
stopped for some time. He therefore determined to go on at once with the
launching operations.
The result of the test was very satisfactory to him, and it enabled him
to carry on the work with the same confidence as he had at the first
felt--‘that the ship may stop halfway or not move at all ... but no
injury to the ship can result from any failure in the course of
proceeding in this mode of launching.’
Shortly before the second attempt to move the ship, on November 19, the
experimental cradle had been again put up with a view of obtaining some
additional data as to the hauling strain that might be required. The
deductions made from them were the same as those obtained in the
commencement of the year, and encouraged the hope that the motive power
required would not be excessive.[167]
* * * * *
By Saturday, November 28, the four presses had been got ready; and the
river tackle, though still far from being beyond reproach, had been got
into place, and partly tested.
The brakes were eased, and a small amount of slack was overhauled on
the check-tackle chains by the men stationed on the ways for that
purpose. As on the previous occasion, the pressure was to be first put
on the presses at the foremost cradle.
Arrangements were made for promptly following up the ship if she moved
freely. A black board was placed on each cradle for recording the
progress of the ship.
Mr. Brunel stood on a low platform in the centre of the yard, as a
convenient position from which to watch and command the operations. A
little before ten he gave the order to commence pumping, and the men at
the hydraulic presses got to work. When the pressure came on the timber
framing which formed the abutments, there was considerable noise of
creaking and crushing as the several parts subjected to strain came in
to their proper bearing. The men soon changed from the large plunger
handle to the small one which put on the full pressure; the timbers of
the abutments kept on crying out, but it was evident that they were not
yielding as they had done before. Presently, while the noise of the
timber-work was still attracting attention, the man in charge of the
measuring apparatus recorded on his black board a movement of one inch;
the ship was again in motion.
She moved steadily, but slowly, under the force of the presses, at a
rate of about one inch a minute, and as soon as the forward cradle had
been moved about a foot in this way, the presses at the after-ways were
set to work, and the river tackle was put into operation, first the bow
and stern tackle, and then the four middle purchases. All went well with
the presses, but the strain had not been put on long, when the stern
mooring-chain and one of the two chains at the bow broke; an anchor at
the bow had also begun to drag.
Later in the day part of the moorings of the centre barges also gave
way. Captain Harrison set to work to repair these defects as fast as
they occurred; in no way dismayed that, as he was at work remedying one
mishap, the news of another was brought to him. Barges had to be got
into place, the broken ends of cables fished up or under-run and pieced
together, and this often in the dark; for it must be remembered that the
work was going on at the end of November, when the sun rose, invisible
for fog, at half-past seven, and set at half-past four.
With the exception of the river tackle, all had gone well; the presses
and their abutments had acted efficiently, and the ship had been moved
easily down the ways about 14 feet before work was suspended at night.
* * * * *
Though the progress had not been great, there still seemed a reasonable
hope that, by pushing on, the ship might be got down to the bottom of
the ways in time for floating her off at the next spring-tides, namely,
on December 2. Mr. Brunel therefore decided to go on with the operation
on the Sunday. Early in the morning the presses and crabs were again set
to work. The river tackle soon gave way; and, indeed, there was no
reason why it should be superior to that used the day before, as almost
all that could be done in the night was to piece together the broken
chains, and to replace the anchors. The moorings at the bow and stern
began at once to drag, and two of the mooring-chains amidships parted.
The hydraulic presses were then the only available power; and, although
the full pressure was put on, the ship did not move. This was very
disheartening; it was, however, thought that the resistance was due to
some exceptional adhesion. Every effort was therefore made to get
together the means of giving the ship a first start.
It was not till the afternoon that a large number of screw-jacks and
hydraulic jacks which had been procured were got into place; they were
then screwed up hard, and the hydraulic presses being set to work, the
ship began to move in a manner very similar to that of the day before.
There was not, however, much daylight left; and, when night came on, the
distance traversed was only about 8 feet. The comparative facility with
which the ship moved when once started gave hopes that good progress
might be made the next day.
* * * * *
On Monday morning the ship moved without more difficulty than when she
had stopped the evening before, and the work went on quite
satisfactorily. She continued to move slowly, and by dinner-time had
gone about 8½ feet. Three feet an hour was not much, but still if it
could be kept up it would suffice to get the ship down by the next
spring-tides. Arrangements were therefore commenced for lighting up the
ways and pumping machinery, so that the work might be continued through
the night. The repairs of the river tackle were pushed on, the ship’s
anchors, which had just been finished and tested, were laid down for
part of the moorings, and some of the chains were replaced with chains
lent by the Government and by Messrs. Brown and Lenox.
When work was recommenced after dinner the ship made a short slip of
about 7 inches. On pressure being again applied the 10-inch press at the
forward cradle burst. This put an end to all work for the day, and it
was then determined to replace the broken press and to add two more
presses to each cradle, before proceeding with the launch.
* * * * *
The preparations for the new presses were pushed on vigorously, but it
was not till the afternoon of Thursday, December 3, that things were
again ready for a start.
The pumps were set to work and the tackle hauled upon. The ship made
several short slips of a foot or so, and then moved more than 5 feet at
one slide. When darkness set in she had moved about 14 feet, in slips of
greater or less length.[168]
On Friday, December 4, all was ready early, and during the morning
everything went as well as on the day before; but in the afternoon
increased difficulty was found in getting the ship to move, and the
14-inch press at the after cradle burst, as did also a 7-inch cylinder
of one of the coupled presses.
Notwithstanding the delay due to the bursting of the presses, the ship
was moved some 30 feet; but there was no longer any chance of getting
her afloat at the spring-tides, and the increased adhesion gave cause
for the fear that still more power would have to be applied.
* * * * *
On the next day, Saturday, December 5, the ship made a short slip; but,
although the pressure was kept constantly on, no further advance was
made until late in the afternoon. Mr. Brunel then tried suddenly letting
go the strain on the stern tackle. The sudden relief of the side-way
strain on the end of the ship sent a tremor through the hull, which
served to destroy the adhesion, and she slid several inches. This
operation was several times repeated, and although there were a number
of vexatious delays from pushing-pieces giving way and other mishaps,
she was moved by the evening a distance of about 7 feet, the resistance
due to adhesion being very great.
* * * * *
On Sunday some of the presses farthest from the cradles were moved down
the ways nearer to the ship, so as to avoid the necessity of using long
pushing-pieces, which required much attention to prevent their bulging
sideways. The river tackle now consisted of the bow and stern
steam-engine purchases, and two crabs and tackle, one at each end of the
ship. The moorings opposite the centre of the ship having proved
worthless, it was necessary to lay down new moorings, and it was found
more convenient to lay them opposite the ends of the ship.
* * * * *
The next day, Monday the 7th, after the commencement of operations,
considerable delay was caused by the failure of some of the feed pipes
of the presses. These defects were not cured till after dinner-time,
when the operations were resumed, and before dark the ship was moved
about 6 feet.
On the following morning several short slips were made, and the ship had
been moved about 4½ feet; but, at 10 o’clock, a dense fog came on, and
rendered it impossible to proceed. The next day was occupied in
re-arranging the tackle and presses.
* * * * *
These were not ready till the morning of Thursday, December 10; when, on
the presses being again set to work, and one of the chains being as
before suddenly slackened, the ship made one slip of a little over a
foot; but, on the strain being again applied, two of the anchors began
to drag. As it was now essential to have the river tackle, in order by
shaking the ship to destroy the adhesion, and by the drag of the
catenaries to increase the length of the slides, Mr. Brunel determined
to dispense with the anchors, and to attach the chain cables to piles
connected by framework. These abutments or pulling points for the chains
were now constructed on the other side of the river, opposite the bow
and stern of the ship.
* * * * *
The launching operations last described, namely, from December 3 to
December 10, were full of incident. Nor was the scene wanting in that
animation which agreeably interests a bystander, the more so if he is
not thoroughly conversant with the meaning of all he sees and hears, so
that he mistakes a loudly spoken word, loudly spoken merely that it may
be plainly heard, for a prompt and urgent command.
The labourers at the pumps relieved the monotony of their work, and
shook off the cold, by taking a lively and talkative interest in the
progress of the launch, and echoed the orders given them to pump with
the ‘big plunger,’ or ‘little plunger’ of the pumps, or to ‘fleet’ the
press. This and the singing of the gangs, which were constantly at work
moving chains for the repair of the river tackle, or rolling logs of
timber on to the ways to serve as pushing-pieces for the presses, gave
plenty of life to the operations; and then when the pressure had been
got on the presses, and shouts from the bow and stern of the ship passed
the word that the river tackle was hauled taut, the order would be given
to ‘let go’ the chain at one end of the ship. Immediately the rattling
noise announced that this had been done, and, after a second or two of
anxious watching, the ship slid off, the timbers, abutments, and
pushing-pieces creaking and groaning as the strain was suddenly
relieved. While the ship was in motion, the whole of the ground forming
the yard would perceptibly shake, or rather sway, on the discharge of
the power stored up in the presses and their abutments. The appearance
of the ship moving sideways in these short slips, when seen from the
ways, was very imposing.
All these somewhat striking surroundings of the operations were
naturally heightened in effect, when the work was being carried on in
the early morning or late in the afternoon; and when the timber-framing
and the groups of men at work were illuminated by the glare from the
open fires which were kept burning near the pumps and presses.
* * * * *
The preparations already described were not completed till December 15.
In the meantime Mr. Brunel had been joined by his friend Mr. Robert
Stephenson. Mr. Stephenson had not been aware of many vexatious
circumstances which had even prevented Mr. Brunel from making full use
of his own staff of assistants. Mr. Stephenson expressed to a common
friend his regret that Mr. Brunel had not invited him down to the ship,
and said that he should have gone down uninvited, but that he thought
Mr. Brunel had reasons for not wishing it. On the state of affairs being
explained to him, Mr. Stephenson said, ‘I’ll go down to him at once;’ he
did so, and his arrival at Millwall was very welcome to Mr. Brunel.[169]
Mr. Stephenson agreed with Mr. Brunel as to the expediency of
suspending operations until an ample excess of power was applied.
Fortified by the support of Mr. Stephenson, Mr. Brunel was prepared to
advise the Directors to adopt this course; but, as the preparations for
recommencing the work were just completed, it was determined to make a
trial on the afternoon of December 15. The presses were all pumped up,
and the river tackle hauled on; but, although the force applied was at
least 300 or 400 tons greater than that which had last moved her, the
ship did not yield, and the attempt was abandoned. After a careful
consultation on the depressing result of this day’s work, it was
determined to make another attempt the next morning, in order to see if
any new form of difficulty had arisen; and that after this operations
should be suspended, and an ample number of additional presses provided.
* * * * *
The following day, December 16, as soon as Mr. Brunel and Mr. Stephenson
had arrived, the pressure was again put on the presses, and the river
tackle having been hauled taut, the chains at the bow were let go, and,
to the great satisfaction of all present, the ship made a short slide.
The record of her movement showed that, although the adhesion was much
greater, the retarding force of friction was about the same as before,
and that therefore there was no reason to assume the existence of any
special obstacle. Another short slip was made; but, in getting up the
pressure again, a press was burst, and the work was then stopped.[170]
Mr. Brunel’s decision to suspend the launching operations at this point
was approved at a meeting of the principal shareholders held the next
day. His report to the Directors, and a memorandum of a verbal statement
which he made to the meeting, are as follows:--
December 17, 1857.
In my letter of October 23, which was published at the time in the
daily papers, I referred to the possible contingency of the power
provided to move the vessel down the ways proving insufficient, and
the operation then about to be attempted being so far unsuccessful;
and, referring to what I considered a countervailing advantage in
the absence of risk, I stated, ‘the ship may stop half-way, or may
not move at all, more power may have to be applied, but no injury
to the ship can result from any failure in the course of proceeding
in this mode of launching.’
The result has been that after moving the vessel nearly half the
distance to low water, it has become necessary to increase very
considerably the power which has effected this much, although it
had already been much added to during the operation.
This will unavoidably be attended with some expense and delay, but
not considerable, as the requisite hydraulic presses can be
obtained ready made, and their application is simple, and the
result cannot, I apprehend, be doubtful.
I do not mean to imply that I contemplated any such great increase
of resistance as probable, such experiments as could be made before
moving the ship having given me good reason to hope for a different
result; but the possibility of it was contemplated, and I refer to
this merely as explaining the statement I now make, that the
difficulty is simply one of degree, of more or less power being
required, and that nothing whatever has occurred to create any new
class of difficulty. The launching ways, about which anxiety had
been expressed, and not unnaturally, have stood perfectly and
without any settlement or any derangement by being passed over.
There is no change of gradient or inclination in the ways capable
of producing any effect, as has been supposed; the upper part of
the ways having an inclination of 1·025 inches per foot, and the
lower part, where the ship now is, one of 1·000 per foot, a
difference too small to be appreciable, but which possibly by some
mistake of figures may have led to the erroneous impression
referred to.
The amount of resistance upon the ways in their present condition
and inclination has now been positively ascertained, and an ample
excess of power being applied, there can be no reason to doubt the
result. I propose to apply that excess by going considerably beyond
the amount which the calculation founded upon the results actually
obtained would give as the maximum, and to double the power which
has last moved the vessel.
_Memorandum of a verbal Report made to the Directors, and a small
Meeting of the Principal Proprietors._
December 17, 1857.
That after full consideration of all the circumstances, and
assisted by the best advice I could call in to my aid, namely, that
of my friend Mr. Robert Stephenson, I considered that the only mode
of proceeding, and one which there appeared no reason to doubt
would succeed, was to apply considerably more press power; that I
proposed to double what we had; that I believed I was able to put
my hands upon the requisite presses; that the river tackle so far
as it went might now be considered good, but that unfortunately we
were obliged to take up the principal part of the chains, which
with great kindness and liberality Messrs. Brown and Lenox had lent
us, and were now peremptorily called upon to deliver up; but that
with their assistance I could replace them....
A large number of presses were obtained, the owners for the most part
lending them free of charge. Among these presses was the large one, with
a 20-inch cylinder, which had been used for lifting the tubes of the
Britannia Bridge.
On each of the ways were placed nine presses. The total sectional area
of the cylinders at the forward cradle was 1,066 circular inches, and
that of the cylinders at the after cradle was 1,358 circular inches;
but the Britannia press was not to be worked to its full power, so the
total area of the cylinders may be taken as 2,300 circular inches, or
1,800 square inches. The presses might be considered as good for at
least 2½ tons on the square inch; this gave a power of 4,500 tons,
which, with the 1,000 tons due to gravity, gave 5,500 tons, or equal to
nearly half the weight of the ship. The presses were now coupled
together in groups, in order to ensure that an equal pressure should be
brought on them; and to each of these groups an accurate pressure gauge
was attached.
* * * * *
All the presses having been tested, it was determined to recommence the
actual operation of launching on Tuesday, January 5.
So much of the water in the pipes had been frozen that it was eleven
o’clock before the order was given to the men to pump. When at one group
after another the pressure was shown to be one ton on the circular inch,
the pumps were stopped. As the backing of the presses continued to yield
slightly, a stroke or two of the handles had to be made from time to
time, to keep up the required strain. For six minutes there was perfect
silence, and then the ship moved, sliding down about 3 inches.
The same process was repeated at the stern cradle once or twice, and
then at both cradles. After this the order was given that the pumps
should be kept going till she moved. This was accordingly done, and when
the pressure amounted to 1¼ ton on the circular inch the ship made a
slide of about 4 inches. In this manner she was moved about 5 feet
before work was stopped in the evening.[171]
On January 6, there was a singular change in the behaviour of the ship.
During the whole of the forenoon she moved gradually, yielding to the
pressure at a rate of about an inch in four minutes. In the afternoon,
however, she moved in short slides.
During this and the three following days her progress was about 10 feet
each day. After this the ship, being to a considerable extent
waterborne, was moved with greater ease, and on Tuesday, January 12, 20
feet was accomplished in less than four hours.
* * * * *
By Thursday, the 14th, the ship had traversed a distance of 197 feet at
the forward cradle, and 207 feet at the after cradle. It was thought
unwise to advance further till the coming spring-tides on the 19th of
the month were past, lest an exceptionally high tide might come
unexpectedly, and partially float her. As soon as the spring-tides had
passed, she was moved on cautiously, a short distance at a time, and the
depression of the ways was carefully observed. This was found to be
inconsiderable, and the cradles were gradually pushed 25 feet off the
ways. As the spring-tides came on, water was run into the ship, to
prevent her from floating prematurely.
* * * * *
The upright struts of the cradle on the side next to the river were all
removed, and the wedge-pieces had chains fastened to them, with the ends
brought on deck; so that, if any of the wedge-pieces got jammed and did
not come out when the ship floated, they might be hauled out by the
chains.
The river tackle now consisted of two purchases at the bow and two at
the stern. To keep the ship, when she floated, from being drifted by
the tide or wind, chains were carried from the bow and stern to
moorings, by which her movement up and down stream might be regulated.
Four tugs were in attendance to tow the ship to her berth, and a
floating fire-engine was also ready to pump water into her, should this
be necessary owing to any sudden postponement of the launch.
Nothing now remained but to watch carefully for a suitable tide.
* * * * *
It was determined that, if the weather were favourable, the floating
should be effected on Saturday, January 30. The tides had been below the
average, and on the Friday matters did not look promising; the tides had
continued low, and the weather was bad. A careful watch was kept on the
tide, observations being taken every half hour, and plotted on a diagram
so as to show at a glance the probable height to which it would rise.
The tides showed signs of improvement, and they commenced to pump water
out of the ship on Friday night; but, as time went on, the weather did
not mend, and the wind was blowing from the south-west against her
broadside; therefore in the early morning Mr. Brunel, who was in person
attending each turn of affairs, ordered water to be pumped in by the
fire-engine. There was hard rain and strong wind; and telegrams which,
according to arrangement, were being frequently sent from Liverpool and
Plymouth, showed similar weather. This continued throughout the
Saturday, and the tide was low; but, when it began to rise in the
evening, it gave indications of being a very high one. As soon as the
tide reached the Kingston valves, Mr. Brunel had water run into the
ship. Although she rested uneasily on the cradles, she remained safely
in her position.
In the evening the rain came down in torrents; nevertheless, after
midnight the weather mended, and the wind went round to the north-east.
As the telegraph gave the same report from Liverpool, Mr. Brunel,
encouraged by every sign of fine weather, and having the good promise
given by the high tide of the night before, determined early on the
morning of Sunday, January 31, to float the ship on that day.
The pumps were immediately started to discharge the water from the ship.
The bolts securing the wedge-pieces of the cradles were unfastened at
daybreak, and the ship was then ready.
The morning broke with great splendour after the gloom of the previous
days, and the tide, as soon as it had turned, began to rise with unusual
rapidity. It had been arranged that all the men should be at their posts
at the presses and crabs by eleven o’clock; but the tide was not only
very high, but exceptionally early; and, although a considerable margin
had been allowed, it was not sufficient. Mr. Brunel and his assistants
hurried the men to their places, the presses were set to work, and the
ship was put in motion down the ways for the last time.
At a little before one o’clock observations taken by levels showed that
the ship had ceased to descend, although she was still being pushed
forward. Shortly afterwards Captain Harrison, who had gone on board,
sent Mr. Brunel word that all the wedge-pieces had floated up on the
outer side of the ship; and at twenty minutes past one the stern was
seen to be afloat. Mr. Brunel had been loath to haul out the ship by the
river tackle, lest the wedge-pieces might get jammed; but, as soon as he
was informed that they had floated up, he sent orders for a strain to be
put on the bow tackle. This was at once done, and by twenty minutes to
two the bow rose from the cradle.
Mr. Brunel then ordered the checking gear to be secured, that the ship
might be sooner hauled clear of the cradles, and he went on board. He
had scarcely done so when a serious difficulty arose. It has been
already said, that in order to keep the ship from moving up or down
stream, cables had been carried out to moorings ahead and astern; and
both these chains had been hauled up tolerably taut, at least the slack
had been taken out of them, so that if required they might be at once
available. Now when Mr. Brunel had given the order for the bow out-haul
tackle to be hauled upon, Captain Harrison, in order to supplement it,
ordered the tug-boats to haul the bow off. This order was by some one
conceived to have been given with the object of hauling the ship ahead;
and to facilitate this the stern mooring-chain was let go.
By this time, though the tide was still running up the river, its
strength was much diminished; and the drag of the chain at the bow of
the ship was sufficient to pull her forward against the tide. The
paddlewheel on the shore side then came in contact with the upright
timbers of the forward cradle. Mr. Brunel ran down from the ship into a
boat and examined the place where the wheel was fouled. He then hurried
back on board, where, as through some blunder the stern outhaul had also
been let go, he had now little but the tug-boats to depend upon. They
were of course of but small value for a dead pull as compared with the
chain tackle. He had the bow chain veered out and the tugs all set to
work, assisted by the tide, to haul the ship up the river.
In about twenty minutes time, the paddlewheel was got clear of the
cradle, and this great difficulty was overcome. Fortunately, the tide
was an extraordinarily high one, and the time of available high water
was long.
* * * * *
The ship had not been moved far towards her berth when another mishap
delayed her progress. The barge of the bow purchase came foul of the
starboard paddlewheel, and the only way of freeing the ship was to
scuttle the barge. When this was done it sank away clear of the wheel,
and the ship proceeded to her berth on the Deptford side of the
river.[172]
* * * * *
By about seven o’clock she was safely moored; and the cheers of the men,
as Mr. Brunel went down her side, announced that the launch of the
‘Great Eastern’ was at length accomplished.
NOTE A (pp. 348, 368, 372).
_Experiments and Observations on Friction._
In January 1857, Mr. Brunel took steps to form an estimate of the
amount of hauling or of retarding force that would probably be
required in the launch.
Two rails were laid at an inclination of 1 in 12, and upon them an
experimental cradle was placed, with three cross-bars similar to
those which were to form the under surface of the cradles. The
three cross-bars therefore made six intersections on the two rails,
and the small cradle was loaded with about 8 tons, so that the
weight on each intersection was about equal to that which would
come on each of the intersections of the actual cradle. This
arrangement was not therefore a model, but a correct representation
of a part of the cradles, and which might, with an exception to be
noted presently, be taken to exactly represent, by its conduct, the
conduct of every similar part of the actual cradles. Experiments
were made with one or two kinds of unguents, and, what was a more
correct representation of what was likely to occur, with the rails
and bars clean but not bright, and without lubrication.
The experiments with lubrication were useful rather as comparing
the various lubricants one with another than as representing, by a
mere process of multiplication, what would be the behaviour of the
ship on her cradles, because, for the reason already pointed out in
the case of wooden sliding-surfaces, the lubrication would be more
and more rubbed away as more of the cradle passed over it; thus the
experimental cradle, when tried with lubrication, represented
rather the behaviour of the front part of the cradle than that of
the whole. Had the ship herself been moved uninterruptedly down the
ways, the state of things would have been something between good
lubrication and none at all. As the under sides of the bars were
lubricated, any motion of one end of the ship before the other
would tend to move the bars sideways over the rails, and so to
spread the lubrication, and to pick it up and re-deposit it. Mr.
Brunel thought but little of the black-leading of the ways,
considering that it would be rubbed off by the leading bars of the
cradles; but a very little lubrication on metal surfaces is
sufficient; and doubtless, had the ship been moved continuously
down the ways, considerable assistance would have been derived from
the lubrication which was applied.
The results of the experiment were curious. The generally received
notion is, that friction between rubbing surfaces is independent of
the velocity; that is to say, that whether a body be moving fast or
slow within reasonable limits, the retardation due to friction is
the same; that if a body be sliding at a given velocity, whether
that velocity be great or small, a drag of a certain number of
pounds will keep it moving at that velocity. It was, however,
always understood that a greater force was necessary to start a
body from rest, to overcome adhesion. The experiments made with the
experimental cradle distinctly showed that any rule as to friction
being constant at different velocities was untrue. It was evident
that, as the speed increased, the power required to overcome the
friction became less. No exact records are extant of the
experiments made with this experimental cradle before the launch;
they were, however, repeated during the launch with great care, and
the results very carefully analysed. The experiments showed
generally that the tractive force, including the action of gravity,
was never more than ⅛, or less than 1/15, of the weight.
Although the experiments showed that the amount of friction in the
case of the actual launch would lie between the limits above
mentioned, they at the same time indicated that it would not
probably approach either of those limits.
* * * * *
Shortly after the commencement of the launch, Mr. Brunel had the
experimental cradle and ways re-erected. A very simple arrangement
was fitted up, by which the forces at work at each period of the
progress of the cradle in each experiment might be deduced. The
results of these experiments, which, as may be supposed, were
similar to those obtained in the commencement of the year, were
most instructive; they showed quantitatively the decided diminution
in friction which took place as the velocity increased, and the
amount of that diminution. The apparatus was very simple. The
experimental cradle, which has already been described, was made to
slide down its ways by a chain attached to a suspended weight. The
weight employed was generally about 5 cwt. After the cradle had run
a certain distance, the weight reached the ground and the cradle
proceeded with the momentum it had obtained. The velocity given to
the cradle down the ways was measured in the following manner. A
long piece of tape was coiled round a reel placed at the top of the
inclined rails or experimental ways, so that it could revolve
freely and pay out the tape as required. One end of this tape was
attached to the cradle, so as to be drawn after it as it ran down
the rails. The tape, as it ran off the reel, passed over a guiding
board over which swung transversely a pendulum arranged to swing
once every quarter of a second. At the lower end of this pendulum
was attached a brush which was filled with paint; and as soon as
the model cradle moved, the pendulum was set oscillating by a
self-acting trigger arrangement. The pendulum in its oscillations
made marks on the tape as it ran out at every quarter of a second
of time. Thus, by an examination of the tape, could be determined
the exact distance which had been passed over by the cradle during
each quarter of a second of the time during which it was moving.
The rate of progress being thus known, and the actuating force
(gravity acting on the cradle and on the suspended weight) being
also known, it will be understood that the exact amount of the
resisting force, namely, friction, could be calculated exactly, and
this for each moment and position of the descent of the
experimental cradle.
The following results of these experiments were recorded in terms
of the corresponding amounts of tractive force that would be
required to produce similar results in the case of the ship and
cradles, a weight of 12,000 tons.
+------------------------------+-----------------------------+
| | Force in tons required |
| | to move or restrain ship on |
| | incline of 1 in 12 |
+------------------------------+---+------+---+--+---+-------+
|Velocity, feet per second | 0 |0 to 1|·75| 1|1·5| 2 to 3|
+------------------------------+---+------+---+--+---+-------+
| RAILS AND CRADLE BARS. | | | | | |Retard-|
| | | | | | | ing |
| | | | | | |{ 110 |
|No. 1. Ample lubrication | | .. | ..|60| 0 |{ to |
| | | | | | |{ 200 |
|No. 2. Medium lubrication | | 120 | ..|..| 0 | 60 |
|No. 3. Very little lubrication|400| |200|..| 0 | .. |
| {| | 560 | | | | |
|No. 4. No lubrication {| | to | ..|..| 0 | .. |
| {| | 400 | | | | |
+------------------------------+---+------+---+--+---+-------+
+------------------------------+--------------------------------------+
| | Force in tons required to move |
| | a weight equal to the ship on |
| | similar ways, but on the level |
+------------------------------+-----+------+-----+-----+-----+-------+
|Velocity, feet per second | 0 |0 to 1| ·75 | 1 | 1·5 | 2 to 3|
+------------------------------+-----+------+-----+-----+-----+-------+
| RAILS AND CRADLE BARS. | | | | | | |
| | | | | | | |
| | | | | | |{ 890 |
|No. 1. Ample lubrication | | .. | .. |1,060|1,000|{ to |
| | | | | | |{ 800 |
|No. 2. Medium lubrication | | 1,220| .. | .. |1,000| 940 |
|No. 3. Very little lubrication|1,400| .. |1,200| .. |1,000| .. |
| {| | 1,560| | | | |
|No. 4. No lubrication {| | to | .. | .. |1,000| .. |
| {| | 1,400| | | | |
+------------------------------+-----+------+-----+-----+-----+-------+
In every case where a velocity approaching to 3 feet per second was
attained, whether the ways were lubricated or were quite dry, the
model, though there was no tractive force acting on it other than
that of gravity down the incline of 1 in 12, rapidly increased its
speed till it reached the end of the ways.
These experiments are worthy of note for the contradiction, already
referred to, which they gave to the received rules relative to
friction. It will be seen by these experiments, and as will
hereinafter appear from the results of the movements of the ship
herself during the launch, that with different degrees of velocity
very great variation in the friction was apparent, amounting to a
difference of about thirty per cent. in the case of unlubricated
surfaces, according as the velocity was nearly _nil_ or was 1·5
feet per second, which is a comparatively small velocity. The
friction in this case was, on a weight of 12,000 tons, 1,500 tons
at a very low velocity, and but 1,000 tons at a velocity of 1·5
feet a second or about one mile an hour, the friction at the very
low velocity being fifty per cent. greater than that at one mile an
hour.
As soon as the ship began to move by slides, the recording
apparatus of tape and pendulum was applied to record the nature of
the ship’s movements. This apparatus was similar to that already
described. The tape was attached to the bottom of the ship under
her centre of gravity, and recorded the rate of retardation of the
ship when left to herself after the motive appliances had, with the
exception of gravity, ceased to act; and the amount of friction
acting to retard the ship was determined with a very considerable
amount of accuracy.
The best experiments made were on December 7, 8, and 10; and the
results are very interesting. The dirt and rust of the sliding
surfaces had increased the adhesion very much, and a considerable
force was necessary to start the ship. There being no good pressure
gauges to the presses, it was impossible to decide exactly what was
the force required to start the ship, for of course the tape record
gave no information on this point; but there is no doubt it was
considerable, probably 800 or 1,000 tons in addition to gravity,
and was thus far greater than the force to start that had been
observed with the experimental cradle.
But the remarkable fact was that, notwithstanding the deterioration
of the sliding-surfaces as evinced in the increased difficulty in
starting, the friction, when once motion was established, was
proved not to be very largely in excess of that which had been
exhibited in the experiments.
In the various experiments tried, it was shown that when the ship
had a velocity of between 6 and 8 inches per second, the amount of
friction was only about 100 tons in excess of the action of gravity
down the incline; while as the velocity became less, the friction
became greater, till, as the velocity became smaller, the friction
increased from 200 to 300 tons in excess of the action of gravity.
The results obtained by the observations made on the motion of the
ship having shown that its behaviour when in motion accorded with
that of the experimental cradle, there is every reason to believe
that if the ship had ever attained a velocity of 1½ to 2 feet per
second, which might have happened had the river tackle acted well,
the friction would, as in the experimental cradle, have become less
than the action of gravity down the slope, and the brakes would
have had to be employed to check the motion.
NOTE B (p. 384).
_Letter from Mr. Brunel to W. Froude, Esq._
February 2, 1858.
My dear Froude,--It is no news to you to tell you that we have
floated, but still you will perhaps feel sympathetically some
pleasure in hearing of it from me, as I do in writing to you upon
it.
We have in fact gone on well and without mishap since we have
resumed operations with plenty of power; we have not gone very
quickly because our jumps have been small, or we have gone by a
continuous motion--we have had a great deal of this, and all the
last 30 or 40 feet I think, or more, has been so, the power being
_with_ gravity about a quarter of the weight, sometimes
less--occasionally, when the water was high, considerably
less--buoyancy being of course taken duly into the calculation.
Once, when still weighing fully 3,500 tons, and with 1,200 tons of
water in her, making 4,700, less some buoyancy of the cradle, she
moved so easily that they came running to me from the other cradle,
to say that she was moving of herself, and asking what to do.
She certainly had not much more pressure on than we had assumed to
be necessary to overcome all the friction of thrust timbers, &c.,
certainly could not have had above 300 tons of real push to move
2,000
2,000 tons, 2,000 -- ----- (gravity) = 1,833 tons.
12
I think that when the load became much lighter on the rails, that
the mud and even the sand of the Thames form a lubricator and
_rollers_ which offered less resistance than the dry rail, or the
rail with pressure enough to displace the mud or imbed the sand.
Having at last pushed the cradles beyond the rail, and found her
stand well, and moved a few feet more and still stand upright, I
waited for a tide, and arranged a good communication with
Liverpool and Plymouth to telegraph up wind and weather, morning
and night, so as to help in foreseeing a tide.
On Friday morning, at 3 A.M., the tide began to improve, but the
wind was still in the wrong quarter for a good tide, and as I think
I have told you the tides of this month, and of the whole year of
‘58, are very poor. Besides this, it blew a gale. I therefore began
pumping out the water, but stopped at 1,200 tons, and at 10 A.M.,
seeing no improvement in the weather, I filled in by the
fire-engine about 1,300 or 1,400 more, and gave up the attempt, and
very fortunately, as the tide did not rise high enough, and the
wind right on her broadside increased.
On Saturday night things grew worse, and the wind at Liverpool and
Falmouth finished in the evening still SSW. About midnight the wind
lulled, the rain came down in torrents; the wind gradually stole
round to the northward, and the tide came rolling up uncomfortably
quick. I admitted water as soon as it would run in, and only just
prevented her floating; when, if she had, we should have been in a
mess, as our wedge-pieces were not yet unbolted from the bottom,
nor could we in the night have managed the floating, even if all
had been ready, which nothing was. Under these circumstances, the
wedge-piece being bolted was perhaps our security, as she all but
floated; the stern rose 3 inches though we had 3,000 tons of water
in her, the tide rose so high; we began pumping immediately on the
turn of tide, and by half-past 6 A.M. the wind was gentle from the
NNE., and telegraphs came to announce the same in Liverpool, &c. I
therefore determined upon floating.
We pumped away, and at 10 A.M. cleared everything away, and began
our preparations. I had fixed 12 o’clock to begin forcing her
further down, thinking half-past 12 would have been as early as she
would have moved easily, but the tide came rushing up an hour and a
half before its time; and, although I hurried the men to their
posts, we were rather caught napping. The instant we began
pressing, she moved easily, and by a quarter past 1 we had pushed
her centre past the ways, and she began lifting with the tide.
I had a centre station with a chalk board, giving me the curve of
the tide, and two good levels reading off her stem and stern water
marks. Our calculations had proved very correct. In the skew
position I had pushed her to, she began lifting at the stern first,
as she ought to have done, and her bows soon followed the example.
We stopped pushing the cradles, made them fast, and began hauling
out the ship--she moved very slowly of course.
When she began to move out, our first difficulty occurred by a
little mismanagement, or over confidence, on board; our stern chain
was let go, and she forged ahead against the tide by the elastic
strain of the bow chain, and _I think_ also by the tug-boats
pulling too much, which ought not to have been done, and in going
ahead her port paddles caught hold of some cradle timber rising,
with long 2½ inch bolts holding them to the bottom of cradle. No
tug power would have had any effect upon them. But we had two hours
before us, with a promise of an unusual tide; I hurried on board,
and we succeeded in about twenty minutes in getting a little astern
a little out, and getting clear.
We had some mishaps after this, such as fouling one of our barges,
getting it jammed under the paddlewheels, and the barge fast by the
chain tackle dropt overboard. However, we scuttled and sunk the
barge, and got safely across. We had an extraordinary tide, and
several assistances from nature to counteract any of our own
bungling, and got safely across, and she is now moored in her right
place.
Yours faithfully,
I. K. BRUNEL.
William Froude, Esq.
CHAPTER XIII.
_STEAM NAVIGATION--THE ‘GREAT EASTERN’ STEAM-SHIP._
_COMPLETION AND SUBSEQUENT HISTORY._
A.D. 1858-1859: ÆTATIS 52-54.
A.D. 1859-1870.
PREPARATIONS FOR COMPLETING THE SHIP--FORMATION OF THE GREAT SHIP
COMPANY--MR. BRUNEL’S ABSENCE FROM ENGLAND--PROGRESS OF THE WORKS
FROM HIS RETURN TO HIS LAST ILLNESS--VOYAGE TO WEYMOUTH--EXPLOSION
OF WATER-HEATER--STORM AT HOLYHEAD--DESCRIPTION OF THE SHIP--HER
FIRST VOYAGE TO NEW YORK, JUNE 1860--SECOND VOYAGE TO NEW YORK, MAY
1861--VOYAGE WITH TROOPS TO QUEBEC, JUNE 1861--FRACTURE OF
RUDDER-HEAD AND DESTRUCTION OF PADDLEWHEELS, SEPTEMBER
1861--VOYAGES IN 1862--ACCIDENT OFF MONTAUK POINT, AUGUST 27,
1862--VOYAGES IN 1863--FORMATION OF THE GREAT EASTERN STEAM-SHIP
COMPANY--REMARKS ON THE HISTORY OF THE ‘GREAT EASTERN’ PREVIOUS TO
HER EMPLOYMENT IN LAYING SUBMARINE TELEGRAPH CABLES--TELEGRAPH
EXPEDITIONS OF 1865 AND 1866--FRENCH CABLE EXPEDITION OF
1869--VOYAGE TO BOMBAY AND ADEN, 1869-70--CONCLUDING
REMARKS--_NOTE_: DIMENSIONS OF THE SHIP AND ENGINES.
Soon after the launch of the ‘Great Eastern,’ efforts were made to
obtain funds for finishing her, and Mr. Brunel proceeded to prepare
designs with the view of obtaining tenders for the execution of the
decks, skylights, fittings, rigging, &c. He obtained advice from persons
thoroughly conversant with this class of work; and a specification was
carefully prepared, providing for the completion of the ship in a
perfect manner.
* * * * *
Meanwhile it had been considered that, large as the ship was, she might
be profitably employed in the American trade, and that it might be
expedient to run her on that line for a few voyages before placing her
on the Eastern route. Captain Harrison went to America to examine the
harbour at Portland, and brought back a favourable report of it.
All efforts to raise the funds for finishing the ship proved unavailing;
and it was determined to reconstitute the company.
* * * * *
The new company, which was called the ‘Great Ship Company,’ was formed
towards the end of the year 1858. In the beginning of December, Mr.
Brunel was compelled by ill-health to go to Egypt for the winter. On
leaving England, he strongly urged the Directors on no account to fail
to make a strict contract, distinctly defining the work to be done, and
the manner of its execution, as provided for by the specifications he
had drawn out. But his advice was not followed.
After Mr. Brunel’s return to England in May 1859, he continued to give
the greater part of his time to the ship. The difficulties which he had
to encounter were certainly neither fewer nor less vexatious than those
which had arisen at earlier periods in her history; but they were the
last with which he had to contend.
* * * * *
On September 5 he left her in the morning, feeling the commencement of
the illness which ten days afterwards terminated fatally.
* * * * *
The ship left her moorings on September 7, and with the assistance of
several tugs steamed down the river. She stopped for a night at
Purfleet, and again at the Nore, and then left for Weymouth.
On the voyage a serious accident happened, which was made the subject of
much misrepresentation.
Round each of the funnels of the paddle engines was what was termed a
water-casing, or jacket, consisting of an outer cylinder, about 6 inches
from the inner cylinder which formed the funnel. The top of the annular
space between the cylinders was at about the level of the deck. From it
a stand-pipe was carried up, which, after rising to a certain height,
was turned over, and the end brought down into the stokehole. The object
of this arrangement was to heat the feed-water before it entered the
boiler, and at the same time to keep the saloons cool, through which the
funnels passed. The arrangement of the stand-pipe gave this advantage,
that when the head of water in the heater and stand-pipe together became
equivalent to the pressure in the boiler, the water could be run into
the boiler by gravitation. The stand-pipe at the same time, being open
to the air at the top, formed a safety-valve to the water-heater.
For the purpose of testing the joints of the jacket with water pressure,
while the ship was being finished, a stop-cock had been placed on the
stand-pipe, which unfortunately had not been afterwards removed. While
the ship was proceeding down Channel, the donkey feed-pumps were not
working well, and to ease them it was thought better to cut off the
water-heater, and to force the water direct into the boiler. The
communication of the water-heater with the boiler was therefore cut off;
and, as was afterwards ascertained, the stop-cock at the top of the
water-heater had been also closed. The water confined in the heater soon
produced steam, and when the ship was off Hastings the casing exploded.
The funnel was thrown up on to the deck, and a body of boiling water and
steam was driven down into the boiler room, severely injuring several of
the firemen, who afterwards died.
That the effects of this accident were confined to one compartment of
the ship, was due to the complete protection afforded by the transverse
bulkheads.
After she arrived at Weymouth the funnel was repaired; but as an outcry
was raised against the water-heaters, it was thought desirable, from
deference to public opinion, to discontinue their use; although this
accident had not in any way proved them to be objectionable, and they
are now generally adopted.
While the ‘Great Eastern’ was at Weymouth Mr. Brunel died.
Many visitors went in the ship when she left Weymouth on a trial trip to
Holyhead. At Holyhead she lay in a somewhat exposed situation; and the
sudden storm came on in which the ‘Royal Charter’ was lost. The great
advantage of having both paddle and screw was now, for the first time,
felt. A portion of the temporary staging erected by the contractor at
the breakwater was carried away, and drifted down upon the ship. During
the gale her engines were kept going, in order to relieve the strain on
the cables. The timbers of the staging got foul of both paddlewheels and
screw; but, as it was always possible to keep one of the engines at
work, the ship was saved from drifting.
The season being now too far advanced for a profitable voyage to
America, the ship left Holyhead and went to Southampton Water for the
winter, where several alterations and additions were made.
In Mr. Brunel’s report of February 5, 1855, printed above, at p. 315, he
describes the leading features of the ‘Great Eastern’ as she was then
being constructed, but a more detailed account of them will fitly
precede the history of her career as a passenger-ship.
The main arrangements of the ship are shown in the woodcut (fig. 16, p.
397).[173]
The ship is 680 feet long, 83 feet wide, and 58 feet deep. Her gross
tonnage is 18,915 tons. She is divided into water-tight compartments by
ten bulkheads (_a_ and _b_), all of which, except two (_b_), extend
completely across the ship, and up to the upper deck. These two are
complete to 6 feet above the 28-foot water line. In addition there are
partial bulkheads (_c_), which form the ends of coal bunkers, and aid
materially in strengthening the flat bottom of the ship. The more
remarkable parts of the construction of the ship will be understood by
means of the transverse section. The bottom is made double, and between
the two skins are webs, running longitudinally. Mr. Brunel considered
that the double skin would greatly diminish the chance of such an
accident occurring as would cause any of the compartments to be filled
with water. The material being arranged in the direction of the length
of the ship is all capable of taking part in the strains that are thrown
on the bottom, as well as on the top, by forces tending to bend the
ship.
Mr. Brunel also made the upper deck cellular, in order to resist the
compressive strain that would come on it when the ship was heavily
loaded in the middle of her length. Great additional strength to the
ship, considered as a girder, is given by two longitudinal bulkheads, 36
feet apart, extending for 350 feet. These bulkheads, with the sides of
the ship, form the vertical web plates of the girder. Her structure
resembles the tubes of the Britannia bridge; the cellular top flange
being connected with the cellular bottom flange by plate-iron webs.
[Illustration: Fig. 16. _Longitudinal Section_
_Plan showing Machinery and Coals_
_Midship Section showing Cabins and Boiler Room._
‘GREAT EASTERN’ STEAM-SHIP
_a._ Complete transverse watertight bulkhead
_b._ Transverse watertight bulkheads complete up to water line
_c._ Partial transverse bulkheads
_d._ Longitudinal bulkheads
E. Cable decks
F. Chain cable lockers, &c.
G. Ice-house, stores, &c.
H. Forward cargo space
I. Paddle boiler rooms
J. Paddle engines
K. Cross coal bunkers
L. Paddle auxiliary engines
M. Screw boiler rooms
N. Screw engines
O. Screw auxiliary engines
P. Screw alley
Q. Grand saloon
R. Ladies’ saloon
S,U. Lower saloons
T. Upper saloons
V. Passage tunnel
W. Steam-pipe tunnel
X. Aft cargo space
Y. Aft cable deck, &c.
Y’. Deck for auxiliary tiller, &c.
Z. Cabins
NOTE.--_The masts of the ship, six in number, are not shown on this
woodcut._]
The two skins of the ship, with the web plates between them, forming the
cellular bottom of the great girder, may also be considered as a number
of smaller girders placed side by side, each resisting the excess of the
pressure of the water over the load that may happen to be resting on it
inside the ship. The difference of pressure or upward strain is
transmitted by the cross bulkheads (_a_, _b_, _c_) from the bottom of
the ship to the sides and longitudinal bulkheads.
The double skin extends up to about 6 feet above the water level
throughout the whole length of the ship, with the exception of the
extreme ends.
The foremost compartment next the bow has two cable decks (E), with
capstans and all the necessary riding-bitts, stoppers, and other
appliances for working the cables. These arrangements answer well, and
the 3-inch chain cables are worked with great facility. The capstans
were originally driven by a shaft from the paddle auxiliary engines, but
this was found inconvenient, and a small independent engine has been put
to work them. The cables are stowed in chain lockers on a deck (F) below
the cable decks, and below this (G) are ice-houses and store-rooms. The
next compartment of the ship (H) is intended for cargo. It is at present
occupied by the forward cable tank.
The main part of the ship, 350 feet in length, up to the level of the
lower deck, 34 feet above the bottom, is occupied with her engines,
boilers, and coal bunkers. The space above the lower deck was occupied
with saloons and cabins for passengers, except at the paddle engine room
(J). The boilers, four in number, two in each boiler room (I), which
supply steam to the paddle engines, are placed forward of the engines;
and forward of the boiler rooms is a coal bunker (K), 20 feet long; and
abaft of the paddle engines are the six boilers, two in each boiler room
(M), that supply steam to the screw engines (N). These three boiler
rooms are separated by coal bunkers (K), 20 feet long. On either side of
the boilers and engines, and also upon plate iron arches above the
boilers, are bunkers for coal. This will be seen on the transverse
section of the ship. Between the paddle engines and boilers is a
water-tight compartment, 10 feet long (L), in which are placed a pair of
auxiliary engines of sixty horse-power, which pump water out of the ship
and also work fire-pumps. There are two other auxiliary engines of sixty
horse-power in a compartment (O) aft of the screw engines, intended to
keep the screw propeller turning round, either when the ship is at
anchor, to relieve the strain on the cables, or when, for any reason,
she is only using her paddle engines. They also work bilge-pumps and
fire-pumps. Each set of auxiliary engines has two independent
high-pressure boilers. Throughout the bottom of the ship there are two
bilge-pipes, fitted with valves, with branch-pipes leading to the
various compartments of the double skin. These bilge-pipes can be
connected with either of the auxiliary engines, and so the water can be
pumped out of any part of the ship.
The paddle engines, of 1,000 nominal horse-power, consist of four
inclined oscillating cylinders, 14 feet stroke and 6 feet 2 inches
diameter, each pair of which work on to a single crank. There are means
for disengaging either paddlewheel from the engines.
The screw engines, of 1,600 nominal horse-power, consist of four fixed
horizontal cylinders, 4 feet stroke and 7 feet diameter, the two
cylinders of each pair working opposite to each other on one crank.
In each boiler room are two donkey engines for supplying the boilers
with water, and the main engines are also fitted with feed-pumps. Each
of the donkey engines is capable of pumping water out of the ship, and
of being used in case of fire.
The screw shaft passes along what is termed a screw alley (P). The
weight of the screw rests on the bearing where the screw shaft passes
out through the stern-post of the ship. To prevent the water that leaks
in through this bearing from penetrating into the screw alley, there is
a bulkhead with a stuffing-box round the screw shaft, a short distance
forward of the stern-post. To enable access to be gained to the bearing,
a tube was provided leading down from the main-deck. This was intended
to be fitted with appliances for pumping air in so as to drive the water
out, and to admit men to get at the bearing under air pressure.
Another arrangement was also provided for the same purpose. On the after
side of the stern-post was placed a ring of india-rubber; and, by
pulling in the screw-shaft, the screw was pressed tightly against the
india-rubber ring, which prevented the water from entering. By means of
this arrangement the stern-bearing was examined and repaired at
Southampton.
The screw propeller has four blades, and is 24 feet in diameter and 44
feet pitch. The paddlewheels were 56 feet in diameter, with 30 floats,
each 13 feet broad and 3 feet deep.
Over the boiler rooms run two tunnels; one of them (V) serves as a
passage to enable the engineers to pass from one compartment to another
throughout the part of the ship occupied by the boilers and engines. The
openings leading from the tunnel to the engine or boiler rooms are
provided with watertight doors, which can be shut in the event of any of
the compartments getting full of water. The other tunnel (W) serves as a
passage for the steampipe, which leads from the boilers to the engines.
Though the boilers are divided into two sets, one for the paddle engines
and one for the screw, the steampipes are connected, so that the whole
of the ten boilers, or any of them, may be used to supply steam for
either of the engines.
In one point a deviation was made from Mr. Brunel’s arrangements. It was
his intention that there should be no apertures in the water-tight
bulkheads except at the tunnel (V), from which the various boiler and
engine rooms were to be entered by openings, to be closed by water-tight
doors. The tunnel was placed high up, so that in the event of a leak
there might be ample time to close the door. The inconvenience of
ascending and descending by ladders was, however, considered an evil;
and it was found necessary at times to carry coals from one compartment
to another. For these reasons, upon the requirement of the Board of
Trade, doorways, fitted with sliding doors, which can be closed by
handles on the upper deck, have been cut in the bulkheads between the
boiler rooms. This arrangement exists in other ships; and in the ‘Great
Eastern,’ even without closing these doors, there are eight watertight
compartments.
At the stern of the ship (Y) on the main-deck are arrangements for
working cables, similar to those at the bow.
These appliances are required when the ship has to be moored so as not
to swing with the tide; and they would allow of the ship’s riding by the
stern instead of by the bow, which it might often be useful for her to
do in narrow waters. On the lower deck (Y), at the stern of the ship, is
a spare tiller and wheel for working the rudder, in case anything goes
wrong with the main tiller, which is on the upper deck. The weight of
the rudder is carried on the lower deck by a grooved collar, resting on
a ring of cannon balls.
The compartment (X) immediately aft of the screw engine room is for
cargo.
The saloons and cabins are all in the middle of the length of the ship,
where there is least motion. The usual plan of putting the first-class
passengers at the stern was not adopted, and they were placed forward.
As the smoke generally drifts towards the stern of a ship, the
first-class passengers in the ‘Great Eastern’ are not annoyed by the
smoke, or by the dust and smell from the boiler and engine rooms.
The transverse section shows the arrangement of the cabins.
Mr. Brunel intended that the upper saloons (T) should be used as
sitting-rooms, and the lower saloons (S and U) as dining-rooms. These
were to be lit and ventilated by shafts on either side of the upper
saloons, rising up to the skylights on deck. The smell of dinner was
thus to be kept away from the sitting-rooms. The cabins (Z) on either
side were to be approached from the saloons by passages and steps, as
shown on the section. The saloon marked (Q) is the first-class, and (R)
the ladies’ saloon.
The ship is rigged with six masts. The arrangements of the masts and
rigging were especially intended for the Eastern voyages. At the extreme
bow and stern are low masts, which carry trysails and staysails. The
sails on these masts were chiefly intended for manœuvring the ship.
She also has three large masts, the lower masts being of iron. The two
foremost of these are square-rigged, and all three of them have trysails
and staysails. The aftermost of the three was also made strong enough to
be fitted with square yards, in the event of its being desirable to rig
it in that manner. Aft of the three principal masts is a large mast,
only intended to be rigged with fore-and-aft canvas. The ship has no
bowsprit, the stay of the foremost mast being attached to the stem
inside the bulwarks.
* * * * *
In the beginning of June 1860, the ship made a trip from Southampton
down the Channel, as far as the Start Lighthouse and back, to try her
engines; and on June 17 she sailed for New York, under the command of
Captain Vine Hall, who had succeeded Captain Harrison. She arrived
there, after a prosperous voyage, on June 28, and was received with
great enthusiasm. The ship left New York on August 16, and, having
called at Halifax, arrived at Milford Haven on August 26.
In the course of these two voyages the stern-bearing of the screw-shaft,
which was in white metal, had worn down between two and three inches.
With the view of allowing for any depression of the stern-bearing, the
lengths of the screw-shaft were not rigidly connected throughout, but
the end length, attached to the screw, was coupled to the remainder of
the shaft by a universal joint, consisting of two double cranks. Thus
the two shafts might be, to a considerable extent, out of line, and yet
revolve efficiently.
When the ship returned to Milford Haven, a gridiron was prepared on the
beach, and she was grounded on it; and the screw-shaft was drawn in. By
this time it had become the general opinion that a shaft cased with
brass, and running in lignum-vitæ bearings, was the best. A lathe and
machinery for making the shaft revolve were provided, and fixed in the
stern of the ship; the shaft was turned, and brass collars shrunk on.
The bearing was made with lignum-vitæ, and the brass-covered shaft
replaced in it. It has since worked well, and has shown no signs of
wear.
The ship, commanded by Captain William Thompson, left Milford Haven for
New York on May 1, 1861, and returned to Liverpool from New York on June
4, having made an average speed of 13¾ knots on the outward and 14 knots
on the homeward voyage.
At this time the Government determined to send her out with troops to
Quebec, and she was fitted up for that purpose. She took upwards of
2,500 troops, and about 40 passengers. There were, altogether, about
3,000 persons on board, and 200 artillery horses. Scarcely any of the
troops were placed in the regular passenger part of the ship, as they
were accommodated in the cargo departments (H, X). Thus a much greater
number of men might have been carried in her with perfect comfort. She
was commanded on this voyage by Captain James Kennedy, of the Inman
service. She left Liverpool on June 27, and arrived at Quebec on July 7.
She returned to Liverpool with about 500 passengers in August.
By this time her superiority had become recognised by the regular
travellers between England and America. Those who had been in her found
that, while they passed other ships rolling and pitching in the sea, the
deck of the ‘Great Eastern’ was so steady that it was difficult to
believe that there was a gale blowing;[174] and when, after a
continuance of heavy weather, she began to roll, the motion was so slow
and easy as to be comparatively unimportant.
When she left Liverpool again, there were a considerable number of
passengers, and it seemed as if her success was ensured. She started
under the command of Captain James Walker, on September 10, and three
days afterwards encountered a severe Atlantic gale.
The ship was behaving well, when one of the boats, which hung on davits
outside the ship forward of the paddlewheels, got adrift on the weather
side. Fears were entertained that it might foul the paddlewheel, and the
captain determined to cut it away. The direction of the ship was
altered, in order that the boat might float clear. The ship then resumed
her course; but shortly afterwards fell off, with her broadside to the
sea.
Relieving tackles having been put to assist the men at the wheel, the
tiller was kept hard over, to bring the ship’s head to the wind; but
with no effect. Towards evening, as the seas beat heavily against her
side, first one paddlewheel and then the other was destroyed, being
completely torn away from the central bosses. During the night she lay
in a helpless condition. The gale had been of some duration, and the
waves being large and long, the ship was placed in a very unfavourable
position to receive them; and she rolled considerably.
The next morning, when an officer went to examine the auxiliary tiller
on the lower deck, he discovered that the rudder-head was twisted short
off, just above the point where it entered the ship. The rudder was
still in its place. The accident had most likely happened on the
previous evening, when the ship fell off her course. It had not been
noticed by the men at the helm, perhaps because there were so many of
them at the wheel and relieving-tackles that they held one against the
other; and the broken parts of the rudder-head, grinding together, threw
jerks on to the tiller. The fracture of the rudder-head was caused by
the badness of the workmanship in the interior of the forging.
Attempts were made to get sail on the ship, but without much success;
and with the hope of bringing her head to wind, the screw engines were
reversed.
As soon as the ship was driven astern by the screw, the rudder, being
uncontrolled, was forced round by the rush of water, and it knocked
away the after stern-post.[175] No other harm was done, as the rudder is
secured by a pin into the heel of the ship, and by a collar round the
rudder-head, attached to the hull above water.
Steps were then taken to get command over the rudder. Chains were
wrapped round the stump of the rudder-head inside the ship, and a
certain amount of control was thus obtained. A more effective plan was
at the same time carried into execution. A man was lowered by a rope
from the stern of the ship, who hove a piece of wood, with a line
attached to it, through the screw-opening. The wood with the end of the
line was caught with a boat-hook; and a rope, and afterwards a hawser,
and then a piece of the ship’s chain cable were passed through behind
the rudder. The two ends of the chain cable were brought together at the
stern of the ship, and a large shackle put round both parts of the
chain, and shaken down till it held them together. In the edge of the
rudder-blade a notch had been made by the rudder striking against the
screw, and into this notch the shackle was made to drop. In this way two
chains or pennants had been attached to the back of the rudder. One of
these was brought to each side of the ship, and they were hauled on by
means of the stern capstan.
The ship then turned homeward, and the weather having moderated, she
arrived off Cork harbour on the afternoon of September 17. By this time
the chains round the rudder had shifted, and were of little service; and
before night it began to blow heavily towards the shore. It was
dangerous for the ship to remain on a lee shore; and, although the
steering-gear was out of order, the captain wisely determined to take
advantage of the ship’s head pointing in the right direction, and
steamed out to sea.
Three days afterwards the ship, assisted by several small steamers, was
got safely into Cork harbour, a temporary tiller was attached to the
stump of the rudder-head, and she proceeded to Milford Haven, where she
was placed on the gridiron, and her after stern-post and paddlewheels
replaced. The accident had proved that the original paddlewheels might
with advantage have been made stronger, and in the new wheels the
bracing was increased.
* * * * *
The ship, under the command of Captain Walter Paton, left Milford Haven
for New York on May 7, 1862, and returned to Liverpool on June 11. She
left again on July 1, and returned on August 6. Besides the number of
passengers the ship accommodated, she carried a considerable amount of
cargo; she brought over large quantities of grain and provisions. The
custom of carrying this class of freight in steam-ships received a great
impulse from the success of the ‘Great Eastern’ in the traffic. As it
was found that the shallowness of the bar at Sandy Hook prevented her
taking full advantage of her carrying power, she had on this voyage
followed the route along Long Island Sound, so as to arrive close to New
York in deep water, and on her return voyage she brought as much as
5,300 tons of cargo in bulk, which with 4,350 tons of coal gave her a
mean draught of 28 feet.
She left Liverpool on August 17, and arrived off Montauk Point, at the
entrance to Long Island Sound, at about two in the morning of the 27th,
to take in the pilot. While stopping, a loud rumbling noise was heard,
and presently the ship heeled slightly over to one side. The pilot,
when he came on board, said that the ship had passed over a reef of
sunken rocks, which was not marked on the charts.
It was at the same time found that many of the spaces between the double
skins were full of water. The ship went on to New York, and most of the
passengers landed in ignorance of an accident which in any other vessel
would have been fatal.
* * * * *
Steps were at once taken to examine the damage, and the divers reported
a large fracture in the outer skin 80 feet long and about 10 feet broad.
They also discovered afterwards several smaller fractures. It was
considered that this damage might be mended while the vessel was afloat,
and a very skilful arrangement, contrived by Messrs. Renwick, of New
York, was adopted. A large wooden barge was made with a gunwale shaped
to fit the ship’s side, and two wooden passages leading down into the
barge. It was placed so as to cover the large fracture, and was secured
by chains passed round the bottom of the ship. The joint between the
gunwale of the barge and the ship’s side was made water-tight; the water
was pumped out, and men and materials passed down through the shafts. By
the exertions of those engaged in this difficult operation, the great
fracture was repaired, and the ship returned to England in the beginning
of 1863.
A gridiron was made at Birkenhead; the ship was placed on it, and the
repairs were proceeded with under the direction of Mr. Brereton, who at
Mr. Brunel’s death succeeded him as engineer to the Great Ship Company.
On examination, it was found that fractures had been made in ten
separate places in the outer skin.
The ship started again in May 1863, and made three voyages to New York
and home. At this time, however, there was a severe competition with
other vessels, and the Company could not afford to run the ship
unremuneratively for any length of time. In 1864 she passed into the
hands of a new company, which consisted almost entirely of those who,
from their belief in the capabilities of the ship, had found the money
for starting her again after each of her successive misfortunes.
The ship lay idle for some months, and was then chartered by the
Telegraph Construction and Maintenance Company.
* * * * *
The ‘Great Eastern’ had in the course of the four years from 1860 to
1863 made nine voyages across the Atlantic and back. Though this was not
the route for which she had been intended, it had given her many
opportunities of showing her merits. Adverse fortune had added to these
opportunities, and had at the same time demonstrated the necessity of
many of the precautions which Mr. Brunel had taken to ensure her safety.
* * * * *
The construction of the hull of the ship has been proved by experience
to possess the advantages anticipated by Mr. Brunel.
Its strength as a whole has been proved by the absence of all signs of
weakness in the heavy weather she encountered on several occasions, and
especially in the gale of 1861, when her rudder was disabled. The
strength of the ship has since been fully tested by the enormous loads
she has carried while on telegraph cable expeditions.
The importance of the double skin was shown on the occasion of her
grinding over the rocks at Montauk Point, when so large a number of
leaks were made in all parts of her bottom that no ordinary system of
bulkheads would have saved her from foundering. Moreover, the space
between the two skins was sufficient to allow of the outer skin and the
webs being crushed to the extent of three feet, while they at the same
time acted as a buffer and prevented the inner skin from coming in
contact with the rock.
The engines have not had any opportunity of working at high speed in the
long voyages for which they were intended, but in the rapid and
comparatively short passages made by the ship across the Atlantic they
worked with great regularity and success. Although they were commenced
seventeen years ago, they are still fine specimens of marine engines,
and bear witness to the care taken by their builders in their design and
manufacture.
Of the points on which Mr. Brunel laid stress, and which, as he
remarked, ‘involve no other risk than that of being useless; they cannot
do mischief,’ many have now come to be considered essential parts of
good marine engines. He thought it of great importance that the steam
cylinders should be jacketed, especially at the ends; and it was
intended that the high-pressure steam for this purpose should be taken
from the auxiliary boilers. This plan was, however, not adopted.
Mr. Brunel was also anxious that the steam should be heated immediately
before it entered the cylinders, and that fresh water should be supplied
for the boilers by using the same water over again. Arrangements for
effecting these objects have since been brought into general use.
The advantage of having several cylinders to each engine was shown while
the ship was running to America. Part of the valve-gear of one of the
paddle-engine cylinders gave way, the engines were stopped for four
hours, and the ship was propelled by the screw alone. The cylinder was
disconnected and turned back out of the way, and the engines worked
efficiently with three cylinders for four passages across the Atlantic.
The average speed of the ship on those voyages in which her performances
were fairly tested was about 13½ knots. On two occasions she made the
voyage from New York to Liverpool at an average speed of 14 knots; and
she maintained her speed in rough weather and head winds to a much
greater extent than is the case in smaller vessels.
By having two sets of engines, the ship was saved from serious disaster
at Holyhead, and again in the gale of September 1861.
The great handiness of the ship is one of the many beneficial results of
the use of both paddles and screw. By working the paddlewheels astern
and the screw ahead, she can be kept from moving forward or backward,
and at the same time the stream of water from the screw, acting on the
rudder, makes her answer her helm and turn round on her centre. By
modifying the speed of the two engines, she may be made to creep slowly
forward; and as the rudder is in the full rush of the water driven back
by the screw, the ship has practically as much steering power as she has
when moving rapidly. The importance of this power of controlling her
when passing through narrow channels, in entering and leaving port, can
scarcely be over-estimated.
* * * * *
The career of the ‘Great Eastern’ since the formation of the present
Great Eastern Steam-Ship Company, has been prosperous.
In the commencement of the year 1864, when Mr. Cyrus Field had succeeded
in reviving the project of laying the Atlantic cable, the Telegraph
Construction and Maintenance Company took the contract for laying it,
and hired the ‘Great Eastern.’ She was brought round to Sheerness,
where the cable tanks were fitted into her. One tank was placed in the
forward cargo compartment, and another in the after cargo compartment;
and the largest tank was placed over the middle screw boiler room, the
funnel being removed. Therefore, during the cable-laying expeditions,
the ship only used eight of her boilers.
* * * * *
The history of the laying of the Atlantic cable is well known. The
‘Great Eastern’ started from Valentia on June 23, 1865, under the
command of Captain (now Sir James) Anderson, and the cable was laid more
than half way across the Atlantic; but, on hauling in to recover a
fault, it was broken, and dropped to the bottom of the sea.
The grappling tackle was not sufficiently strong. The cable was three
times partially raised, and each time lost; and the expedition returned
to England defeated, but with the knowledge that ultimate success was
certain.
The engineers and scientific men on board the ‘Great Eastern’ drew up a
memorandum as to the results of this expedition, and, among other
things, stated--‘That the steam-ship “Great Eastern,” from her size and
constant steadiness, and from the control over her afforded by the joint
use of paddles and screw, renders it safe to lay an Atlantic cable in
any weather.’[176]
Sufficient additional cable was made to lay a second one and to finish
the old cable when it should be recovered. The ship started again on
July 13, 1866, and laid the cable across the Atlantic without the
slightest mishap. She then returned, and after three weeks of hard work,
the end of the cable which had been lost the year before was picked up,
and completed to Newfoundland.
On her return to England there did not seem to be any immediate
employment for her in cable laying, and the tanks were taken out. In the
following year a company was formed in France to charter the ship, and
to work her between New York and Brest during the French Exhibition. She
made one voyage from Liverpool to New York and back to Brest and
Liverpool; but the undertaking was a commercial failure.
She remained at Liverpool till October 1868, when it was proposed to lay
a cable from France to America; and she came round to her former berth
at Sheerness. Tanks were made in the fore and aft cargo spaces, and a
very large tank, 75 feet in diameter, was placed amidships. The
bulkheads were cut partially away to make room for it, the ship being
strengthened above and below. She started on this expedition from Brest
under the command of Captain Robert Halpin, and encountered very heavy
weather. The cable was laid successfully.
* * * * *
The ship then returned to England, and was fitted out for the greatest
adventure she has yet undertaken. She was to proceed with a full cargo
of cable round the Cape of Good Hope to Bombay, to lay it thence to
Aden, and from Aden a portion of the way up the Red Sea. With her cable
and coals, on leaving England, she drew 34 feet 6 inches, with the
enormous displacement of 32,724 tons. She laid the cable with perfect
success, and returned to England.
* * * * *
Throughout all these cable-laying expeditions, and especially in the
work of picking up the Atlantic cable of 1865, the good qualities of the
ship have been fully exhibited.
* * * * *
The later voyages of the ‘Great Eastern’ were undertaken for the
accomplishment of a work in which Mr. Brunel had felt a great interest.
In 1856, Mr. Cyrus Field came over to this country in order to consult
English engineers and scientific men upon his project of an Atlantic
cable. It is stated in a work written by Dr. Field,[177] that--
From the beginning Mr. Brunel showed the warmest interest in the
undertaking, and made many suggestions in regard to the form of the
cable and the manner in which it should be laid. He was then
building the ‘Great Eastern,’ and one day he took Mr. Field down to
Blackwall to see it, and said, ‘There is the ship to lay the
Atlantic cable.’
It appears, however, from drawings in Mr. Brunel’s sketch-books that at
this time, and again in 1858, he thought that it would be better to
have a vessel specially built for the work.
He was throughout sanguine as to the ultimate success of the
undertaking, as is shown by the following extract from a letter written
in December 1856:--
I would suggest a more moderate expression of doubts of the
successful results of the American cable. The impossibility of
running steamers profitably over the surface of the same sea was,
though it is now denied, asserted and proved from established facts
just as clearly as the impossibility asserted now to exist in
respect of the electric telegraph. It is a pity in these days to
lay down any such dogma. Every day’s experience proves that
nine-tenths of them are refuted; that the circumstances do not
prove to be such as are assumed, or the difficulties are overcome;
and however correct the arguments may have been, the result is not
as predicted.
The ‘Great Eastern’ has not yet been engaged on the work for which she
was originally designed by Mr. Brunel; but her employment in the
promotion of great scientific enterprises has been an occupation worthy
of her connection with his name.
NOTE (p. 395).
_Dimensions of the ‘Great Eastern’ Steam-ship._
Extreme length, 693 feet
Length between perpendiculars, 680 "
Breadth, 83 "
Depth, 58 "
Greatest draught of water, 30 "
Registered tonnage, 13,343 tons
Gross tonnage, 18,915 "
Displacement at 30 feet draught, 27,419 "
DIMENSIONS OF PADDLE-ENGINES.
(1,000 nominal horse-power.)
Number of cylinders, 4
Diameter of cylinders, 6 feet 2 inches
Length of stroke, 14 feet
Number of boilers, 4
DIMENSIONS OF SCREW-ENGINES.
(1,600 nominal horse-power.)
Number of cylinders, 4
Diameter of cylinders, 7 feet
Length of stroke, 4 "
Number of boilers, 6
CHAPTER XIV.
_DOCK AND PIER WORKS._
A.D. 1831--1859. ÆTATIS 26--54.
MONKWEARMOUTH DOCKS, 1831--BRISTOL DOCKS, FLOATING HARBOUR,
1832--PROPOSED WORKS AT PORTISHEAD--NEW LOCK AT BRISTOL,
1845--PLYMOUTH GREAT WESTERN DOCKS, 1847--BRITON FERRY DOCKS,
1851--BRENTFORD DOCK, 1856--PIER AT MILFORD HAVEN, 1857.
Mr. Brunel’s dock and pier works are interesting, not only in their
general features, but also in the details of their construction; and the
plans he made for large docks at Monkwearmouth in 1831, which he carried
out on a smaller scale shortly afterwards, were among the earliest of
his independent designs.
With the exception of the gates of this dock, which are of timber, all
the dock gates Mr. Brunel constructed are of wrought iron. This material
had been employed in ship-building before Mr. Brunel adopted it for the
gates of the new lock at Bristol, and it was also beginning to be
extensively used for bridge girders.
At the same time that he introduced the use of wrought iron into dock
gates, he constructed them with a large amount of buoyancy, in order
that they might be moved easily, while being opened and shut.
The dock and pier works which he constructed are at Monkwearmouth,
Bristol, Plymouth, Briton Ferry, Brentford, and at Neyland, Milford
Haven. They will be described in this order, which is nearly that of
the dates of their construction.
_Monkwearmouth Docks._
The town of Monkwearmouth is situated at the mouth of the river Wear, on
the north side, and opposite to the towns of Sunderland and
Bishopwearmouth, which extend for about a mile along the south side. In
order to improve the entrance of the river, and to diminish the
sand-banks which lay near its mouth, piers were proposed as early as the
middle of the last century, and were partly built on both sides of the
river before the year 1800. From that date until 1831, although the
question of making docks had been considered, and designs proposed by
different engineers, no steps had been taken for their construction, and
the only works executed for the improvement of the port were the
extension and alteration of the piers already existing. In 1831 designs
for docks to accommodate the increasing traffic were made simultaneously
by Mr. Brunel and Mr. Giles. Mr. Brunel’s docks were to have been on the
north side of the river, and to have had an area of 25 acres, with
quays, warehouses, &c. Mr. Giles’s were to have been on the south side.
Neither of these schemes was approved of by Parliament; but shortly
afterwards a private company was formed for the construction of a dock
on a plan designed by Mr. Brunel, though on a much smaller scale than
his scheme of 1831, the dock being only about 6 acres in area, with a
tidal basin of about an acre and a half. The company encountered
considerable opposition from the authorities of the town of Sunderland,
but succeeded in obtaining a royal charter for the construction of the
dock. They subsequently obtained an Act of Parliament empowering them
to make the entrance from the dock to the river. The dock was
constructed, and eventually became the property of the North Eastern
Railway Company, to whom it now belongs; they have erected coal drops
along the quay, and have made it a shipping place for collieries
connected with their railway.
The work was begun in 1834, and the dock and tidal basin occupy part of
the site chosen by Mr. Brunel for his larger scheme of 1831.
The quay wall was built with a curved batter, the chord line joining the
top and bottom having an inclination of 1 in 5. The masonry was carried
up in courses, and made solid by filling every part thoroughly with
mortar. A course at the face and at the back of the wall was built up;
an abundance of mortar was then spread in the heart of the wall, and the
stones built in the mortar. Thus no crevices could be left in any part
of the work, and the back of the wall was soundly built throughout.
The entrance to the dock is 45 feet wide, with side walls of the same
profile as the quay wall. Except at the gate floors, there is a
segmental invert of dressed stone of such curvature that it is 6 feet 6
inches lower in the middle than at the side walls. The gate floors are
formed with inverts, curved to correspond with the under sides of the
gates.
The masonry of the entrance was executed within a four-sided coffer-dam,
the sides of which were slightly convex outwards. This coffer-dam was
constructed in the usual way, there being two rows of close piling with
puddle between them; and it was strengthened by internal horizontal
shores which connected the opposite sides, and by diagonal bracing. The
piles were driven until they met with so much resistance as to render it
unsafe to drive them farther. When the ground inside the coffer-dam was
excavated, it was found that the piles had been driven into sand and
gravel, and that, to enable the masonry to be built on a good
foundation, it would be necessary to excavate about 7 or 8 feet below
the piles. They were therefore driven down gradually, as the ground was
removed from the inside, until the requisite depth was obtained. The
whole coffer-dam was thus an immense caisson, the sides of which were
lowered by gradual driving, instead of being simultaneously forced down
by weights.
The masonry of the walls of the tidal basin is similar to that of the
walls of the dock; some parts of the foundation were laid by means of a
diving-bell.
In the entrance between the dock and the tidal basin there is a pair of
gates pointing inwards, which serves to retain the water in the dock
during the fall of the tide, and there is also a pair of storm gates
pointing outwards, which protects the inner pair from the force of the
waves.
The construction of both pairs of gates is similar.
The two leaves of each pair meet at an angle of 125°. Each leaf is about
30 feet long; the bottom beams are curved to the form of the segment of
a circle; the height at the meeting-post is 27 feet, and at the heel
post 22 feet (see woodcut, fig. 17). This arrangement is, to a greater
or less extent, followed in the dock gates Mr. Brunel afterwards
constructed. By raising the pivot, the gate floor can be made of ample
strength, and the cills and heel-posts are free from mud and deposit.
The gates are constructed of horizontal beams of yellow pine timber, 21
inches thick, placed close together for a height of 12 feet above the
bottom. Above this there are beams of timber and of cast iron at
intervals. The whole is planked over on the inner side with 4-inch
planking. The heel-post and meeting-post are socketed into cast-iron
uprights, which also receive the ends of the horizontal beams. To
preserve the gate from any change of form, a diagonal iron tie-bar
extends from the top of the heel-post to the timber beams forming the
lower part of the gate.
[Illustration: Fig. 17. Monkwearmouth Dock Gates.
_Elevation. Section.
Plan.
Scale of feet._]
Nearly under each meeting-post is placed a bevelled cast-iron wheel, 18
inches in diameter, which supports part of the weight of the gate.
There are four sluices in each leaf, placed in pairs, with a small
interval between them. Each pair of sluices counterbalances the weight
of the other pair by being attached to opposite ends of a lever at the
top of the gate. A screw works in the segment of a large worm-wheel
formed on the end of the lever, and, being turned round, opens and shuts
the sluices. After the timber work of the gate had been fitted together,
it was taken to pieces, and subjected to the preserving process called
Kyanising, which consists in immersing the wood in a solution of
corrosive sublimate. This process has been so successful, that when the
gates were recently taken out for examination the timber was found to
be nearly perfect, only slight surface repairs being required in one or
two places.
The great bulk of light wood at the bottom of these gates gives them a
certain amount of flotation at all times of tide. After the gates had
been in use many years it was found that one of the wheels had been
detached for some time, but the buoyancy of the gate had prevented any
mischief resulting. The buoyancy of the lower part of the gate is
somewhat analogous to that of the air-chamber which Mr. Brunel
introduced afterwards in his wrought-iron dock gates.
_Bristol Docks._
About the year 1804 that portion of the river Avon which flows in a
serpentine course through the city of Bristol was enclosed, and the
water in it retained at a constant level, a new cut or shorter channel
being made for the river. The portion separated, called the Floating
Harbour, or Float, is about two miles long and 100 yards broad. At its
lower end it is connected with the river by the Cumberland Basin, a
half-tide basin, with two locks, and at its upper end by a feeder, which
brings the water of the Avon into it, the river in dry weather being
stopped from passing into the new cut by the Neetham Dam, About half-way
up, the Float is entered on the north side by the river Frome; and, a
little above this junction, it is crossed by the Prince’s Street
drawbridge, which divides it into two parts. About 170 feet above the
bridge the Float is connected with the new cut by another basin with a
lock, called Bathurst Basin.
Mud and other deposits had accumulated to such an extent in the
Floating Harbour, that at the end of the year 1832 the directors of the
Dock Company employed Mr. Brunel to suggest remedial measures.
In order to effect his object at the least possible cost, he proposed
certain works, together with an improved system of managing the water of
the river, so as to allow more of it to pass through the Floating
Harbour, by means of which great benefit might fairly be
anticipated.[178] He remarked that,--
By systematically following this course, the object of which is
simply to keep in continual action all the means, however small,
which can at the moment be brought to bear, and thus day by day to
remove or neutralise, or merely diminish (as the case may be), the
continual deposit which is going on--in fact, by applying a
constantly acting remedy to oppose a constantly acting evil--I have
little doubt that the formation of shoals similar to the existing
ones may be entirely prevented, or at all events that they will be
of such a nature as to be easily removed by two or three yearly
scourings, and without that time and labour which are now expended
with so little effect.
It should be observed that the yearly scourings, which became so
objectionable to the trade, were not introduced by Mr. Brunel, but were
part of the original arrangements of the docks.
After the reception of Mr. Brunel’s report, the Dock Company executed
the works which he required, namely, the Sluice, Trunk, and Drag-Boat;
but his other recommendations, as to scouring and increased supply of
water, were only acted upon to a limited extent.
* * * * *
In 1842 the Directors again asked Mr. Brunel to report, in conjunction
with Captain Claxton, upon ‘what further measures are requisite for
keeping the Floating Harbour more clear of mud than it has been for a
few years.’
Mr. Brunel thereupon made a report to the Directors. After having
referred to his previous reports of 1833 and 1834, he remarked that ‘the
efficiency of the whole system then recommended and adopted, and
subsequently partially carried out, depended entirely and was founded on
the supposition of the then existing mud-banks and shoals being first
removed, and the Float deepened at once to the full extent required,’
according to the plans which he had pointed out; and that ‘the
increasing the supply of water through the Float was one of those means
on which he had most insisted’ as necessary for keeping it clean and
preventing its becoming a settling reservoir. He then continued,--
The sluice at Prince’s Street Bridge, the trunk--or syphon, as it
was originally, and perhaps more correctly, called--at the
underfalls, and the drag-boat have alone been brought into
operation. These were originally intended as mere aids, which, in
conjunction with _the increased supply of water_, were expected,
after the complete deepening of the Float, to be sufficient, with
_two or three yearly scourings_, to keep it to the required depth:
these were (perhaps unfortunately) found so effective as to induce
a hope that they might be depended upon solely for the removal of
the evil. The permanent interests of the port were, I cannot but
think, sacrificed to temporary convenience: the scourings which
were required as a preliminary step to restore the Float to its
original state, or to that which was said to have been its former
state, and which is now required, were indefinitely postponed.
A material improvement being notwithstanding soon perceptible from
the first effects of the drag-boat and the removal of mud through
the trunk, the periodical scourings which formed part of the system
approved of for adoption were in a great measure given up to the
objections of the traders. The precautions actually necessary
against admitting into the Float the tide water of the Avon,
heavily charged with mud, were gradually sacrificed for the same
reasons. From all these and many other, but very similar,
circumstances no further progress has been made since the first
improvement, which was felt to be, and which unquestionably was at
the time, very considerable. For until this period it had been the
general practice to lighten all deeply laden vessels at the
entrance of the Float; and, notwithstanding this precaution, it
must be in the recollection of everybody that it was a common sight
to see several large vessels aground at various shoals in the
Float, and unable, without further discharging the cargoes, and
without great consumption of time, labour, and ropes, to get up to
the quays. For several years past the grounding of the deepest
vessels has been the exception, not the rule, but during all this
period it has been one continued and almost vain attempt to
struggle against the old difficulties with insufficient means.
* * * * *
For the removal of such deposits as will still be formed, I propose
two means; and first as regards those deposits which are
continually going on. These are formed almost entirely of mud,
which, from its want of consistency when first deposited, the great
quantity and the large surface over which it extends, as well as
the great depth of water, cannot, as I have frequently explained,
be easily or economically removed by the ordinary process of
dredging: for this reason I originally proposed the drag-boat in
conjunction with the trunk at the underfalls, and which has, so far
as it has been applied, completely answered my expectations.
I should now propose a similar arrangement for the upper float.
* * * * *
I should propose to make the additional drag-boat thus required of
rather greater power than that now in use, and to construct it so
that a chain of dredging-buckets could be hereafter attached to the
shaft; and, secondly, for the purposes of deepening the hard bottom
of the float, and of removing those banks of hard materials which
have either always existed, or have been allowed to accumulate,
dredging must be resorted to. But I should be disposed to attempt
hand dredging or spooning in the first instance; for, although the
depth of water is great, I believe the work could be executed as
cheaply, or nearly so, as by the steam dredging, as the original
outlay of capital would of course be much less, while the facility
of working at several points at once, or of moving from one berth
to another as the convenience of the trade would best allow, would
be much greater; the operation also would be much more under
command, which, taking into consideration the possibility of
undermining the foundations of the quay walls or buildings, is not
an unimportant advantage.
When the required depths are once obtained, the natural deposits
even of the harder description may probably be easily removed by
the drag-boat or by the occasional use of hand dredging.
The recommendations contained in this report were not adopted.
In 1839 Mr. Brunel, in a report to a Committee of the Council of the
City of Bristol, suggested several improvements connected with the Port,
almost all of which have since been undertaken. He proposed to
straighten and widen the course of the river, and to make new locks,
both from the river to Cumberland Basin and from that basin to the
Floating Harbour, or, as an alternative, to construct docks at Sea
Mills, a creek on the Avon, about two miles below Bristol.
He also proposed to construct a large pier at Portishead. The rise of
tide is there sometimes 45 feet, and the velocity of rise or fall as
much as 10 feet per hour. There is also a great deposit of mud by the
Severn. Mr. Brunel considered that these circumstances rendered a fixed
structure undesirable, and he therefore recommended a floating pier. He
said:--
I propose two or three vessels of 300 or 200 feet of length, built
of iron, as the material cheapest and best adapted to the purpose,
of 16-feet or 20-feet draft of water, and about 30 feet beam,
moored close stem and stern, so as to form one continuous floating
body. Any steamboat or other vessel alongside will of course be on
the same level as the pier; the passengers, on disembarking, will
at once be on a level platform or deck, under shelter, where the
luggage or goods can also be placed; and the communication with the
shore will be effected without steps.... Such a pier would afford
stowage for almost any quantity of coals, fresh water, and general
goods, which could be stored here for embarkation.
In 1847, after an Act had been obtained for making a railway from
Bristol to Portishead, with a pier at the latter place, Mr. Brunel
designed the pier on the plan described in his report of 1839; but the
project was not carried out.
* * * * *
As has been already mentioned, the communication between the lower part
of the Floating Harbour and the river Avon is through the Cumberland
Basin; between this basin and the river were two locks, made at the time
that the Floating Harbour was constructed.
Owing to the increased size of merchant vessels, it had long been in
contemplation to enlarge the entrance. At the time when the ‘Great
Britain’ was built, the northern lock was so narrow that a portion of
the upper masonry had to be removed in order to give room for the ship
to pass from the basin to the river on a spring tide. It was then felt
that the enlargement of one of the locks could no longer be delayed, and
Mr. Brunel was asked to adapt the narrower or southern entrance lock to
the passage of the largest vessels.
Between the two locks was a pier, from which vessels were guided, and
the gates opened or shut. The elongation of the lock was limited by the
length of this pier, as it could not be extended towards the river
without diminishing the area of entrance, nor could it be extended
upwards without lessening the area of Cumberland Basin. Mr. Brunel,
although hampered by this restriction, succeeded in obtaining a lock of
considerable length. He constructed the gates of a single leaf, and
placed the upper gate outside the lock so as to shut against the upper
end of the middle pier, and to swing back when opened into a recess in
the side wall of the Cumberland Basin. He thus avoided the necessity of
finding room on the pier for the machinery to open one of the leaves of
the upper gate. Had the gate been in two leaves, the lock would have
been shortened from 30 to 40 feet. At the lower end he placed the gate
as near the river as possible; and, lest the end of the middle pier
should not be strong enough to withstand the pressure, he secured the
quoin stones, against which the gate closed, by horizontal wrought-iron
bars at different levels, built into the side wall of the lock.
The lock is 262 feet in length between the gates, and 54 feet wide at
the narrowest part.
The masonry is of plain character, all the part below the ashlar coping
being of ordinary fitted rubble of great thickness, solidly built with
hydraulic lime mortar. The ground behind the wall consisted of a wet
silty clay, causing a great pressure against the masonry. The under part
of the body of the lock is formed to a semi-oval cross, section.
The works were commenced by the construction of coffer-dams at each end.
In 1846, when the masonry was approaching completion, a very high tide
took place, and a portion of the upper dam gave way. As some work still
remained to be done at the sill and apron of the lower gate, Mr. Brunel
decided to make a brick dam in the middle of the lock, where the masonry
had been completed. This brick dam was a horizontal arch built on the
bottom of the lock, up to the level of the water in the Floating
Harbour. The abutments were formed by the masonry of the lock walls,
which was notched to receive the bricks of the arch rings. The dam was
28 feet high, only 8 feet thick at the bottom, and 3 feet thick at the
top. It was set in Roman cement, and was completely water-tight. It was
easily and rapidly made, and the cost was small, as compared with what
would have been the cost of repairing the upper dam.
In this lock the chief point of interest consists in its being the first
in which wrought-iron gates were introduced, these gates being at the
same time made buoyant.
Floating caissons had been previously used at the entrances to graving
docks, and in similar situations; indeed at Bristol, a caisson had long
been employed at Prince’s Street Bridge, to separate one part of the
Floating Harbour from the other. The buoyant gates of the Bristol Docks
differ essentially from these vessels, inasmuch as, instead of requiring
to be floated into their places, they turn on a hinge, and do not rise
or fall vertically.
The gates are provided with wheels, but only a small part of the weight
rests on them, as the gates are rendered buoyant by large air-chambers,
formed in the lower part of them.
The upper and lower gates are alike in construction and dimensions, so
that it is only necessary to describe one of them. (See woodcut, fig.
18.)
The extreme length of the gate is 58 feet, and the extreme height 29
feet. In the middle it is about 10 feet wide, the width diminishing to 3
feet at the top. In plan it is curved to resist the pressure of the
water. The gate when closed is not at right angles to the direction of
the length of the lock, but is at an angle of about 12°. The length is
thus scarcely increased, while the travel in being opened and shut is
much reduced. The top is at the level of the water in the Floating
Harbour; so that, when the tide falls, the water in the Cumberland Basin
may be retained at the same height as in the Float.
[Illustration: Fig. 18. Bristol Dock Gate.
_Elevation._ _Section A. B._ _Section C. D._
_Plan._
_Scale of feet._]
The air-chamber is formed by two water-tight decks of wrought-iron
plating, one at the level of half-tide, the other a short distance above
the bottom of the gate. Above the deck forming the top of the
air-chamber, the water, as the tide rises, flows freely into the
interior of the gate, through openings in the face next the dock, so
that when the water is level with the top of the gate, the part above
the air-chamber is full of water, which flows out again if the level of
the water falls.
In ordinary working the gate only needs to be opened or shut when the
water is above the level of half-tide, and therefore at these times the
whole of the air-chamber is immersed. To whatever height the water rises
above this level, the buoyancy remains almost the same, the only change
being caused by the displacement of the iron of the upper part. This
displacement, when the water is level with the top of the gate, amounts
to about six tons.
The size of the air-chamber is so arranged that when the water is level
with the top of the gate it is just afloat; and at half-tide, when the
water is at the level of the top of the air-chamber, there is a weight
of about six tons on the wheels.[179]
The gate is provided with a sluice, by which water may be admitted into
the air-chamber, or allowed to escape when the water outside is at a
lower level; there is also a pump, by which leakage water may be
extracted. The volume of the air-chamber may thus be altered at will,
and the buoyancy may be modified so as to counteract the effect of the
weight of any mud which may be deposited upon the decks of the gate.
There are in each gate two very large double sluices, which are used for
working the lock, and for lowering the water in the Cumberland Basin to
meet the tide. They are also used for scouring away the mud. The
shutting pieces of the gates, which bear against the granite masonry and
form a water-tight joint, were made of Honduras mahogany, a very durable
wood for the purpose. The timber is bedded in creosoted felt and bolted
to the gates; and the pieces are still sound, after the lapse of more
than twenty years.
Underneath the gate are two wheels, slightly conical, 3½ feet diameter
and 1 foot wide, which travel on level cast-iron rails let into the
masonry of the gate floor. There is no heel-post such as is usual in
dock gates, but the gate is hinged to the masonry by wrought-iron
collars and a wrought-iron pin about 8 inches diameter, which is passed
through them. Any portion of the weight of the gate which is not
supported by the flotation of the air-chamber is borne entirely by the
wheels, the arrangement at the hinge being merely for the purpose of
retaining the gate in its position and guiding it in opening or
shutting. The gate is moved by chains, which are attached to the barrels
of powerful crabs, and conveyed through passages formed in the masonry;
at the lower ends of these are chain rollers or broad sheaves, round
which the chains pass. The sheaves are fluted on the circumference, to
ensure their turning readily. When the gates are nearly afloat, they can
be moved with great ease; but at the time of their construction it was
considered essential to provide machinery sufficiently powerful to open
and close them at low water, when the whole weight of each gate, nearly
one hundred tons, rests on the wheels. The crabs and chains were
therefore made much stronger, and were more difficult to move, than if
they had been merely designed to work the gate under ordinary
conditions.
* * * * *
The gates were constructed in Bristol at the Great Western Steamship
Works in 1847. After the lower gate had been tested and proved to be
water-tight, it was launched, and floated with the front surface nearly
level. The positions it would assume under different conditions had been
calculated beforehand. Before it was fixed, the gate was made to float
nearly upright by the admission of water; it was then towed to its
place, and brought into correct position. The hinge-pin was dropped
through the collars, and by admitting water into it, the gate was sunk,
so that it rested upon its wheels. This operation had to be performed
at high water, which only lasted for a short time.
In fixing the upper gate, the water was kept up to the proper level by
the lower gate, and therefore there was no need to do the work quickly.
_Plymouth Great Western Docks._
As it was considered probable that, on the completion of railway
communication, mail packets and other large ocean steamers might make
Plymouth their port of departure, a company was formed in 1846 for the
construction of a dock in Mill-bay, a large inlet in Plymouth Sound near
the entrance to the Hamoaze.
The bay was already protected from the prevailing winds by a pier at its
eastern side constructed by Mr. Rendel.
It was decided to form a wet dock and graving dock at the inner end of
the bay, and to make quay walls along the side of the outer part, to
join the existing pier. A floating pier for large vessels afterwards
became part of the scheme. In 1847 preliminary trials were made as to
the best means of excavating in deep water the limestone rock of which
part of the bottom of the bay consisted; some quay walls were also
constructed and made use of by the shipping.
At the end of 1851 a contract was entered into for the execution of the
whole of the works remaining to be completed; the most important of
these were the entrance, the graving dock, and the completion of the
floating basin.
The progress of the undertaking was much facilitated by Mr. Brunel
giving his sanction to the proposal of the contractors to form a stone
and earth embankment across the mouth of the bay, instead of employing
the usual timber coffer-dams. This embankment, which completely answered
its purpose, was finished by the middle of 1853.
The works now proceeded steadily until they were completed, and at the
end of the year 1856 the dock was opened.
The middle of the embankment was cut through, and an entrance channel
dredged to a level of 8 feet below low water. The remainder of the dam,
being partly protected by masonry walling, was used as a quay, and
served for the protection of the outer basin.
Mr. Brunel had prepared the foundation, and had intended to build a pier
to shelter the entrance gate from the sea, and to assist in pointing
long vessels. The want of this shelter was felt in the gale of October
1857, when the gates were thrown down. In order to avoid any future
casualty, storm gates, or framed struts reaching down to low water
level, were placed immediately behind the entrance gates, so as to
support them against heavy seas.
The dock, which is of oblong shape, has an area of 13 acres, and a
length of quay wall of 3,490 feet. The greater part has a depth of 22
feet below high water at spring tides, or 16 feet at neap tides; the
remainder is 4 feet deeper, or the same depth as the channel in the
outer basin.
The walls are 8½ feet thick at bottom, and 3½ feet at top, and are built
to a curved batter. They reach generally to a depth of 5 feet below low
water, and rest on concrete 12½ feet thick, carried down until a rock
foundation is reached, which in some places is as much as 40 feet below
the bottom of the dock.
To accommodate the larger paddlewheel steamers, the entrances to the
basin and graving dock were made 80 feet in width.
The dock is entered through a short passage, the sill being 13 feet
below low water. The masonry of this entrance has curved battering
sides, with a segmental invert.
The entrance is closed by a pair of wrought-iron buoyant gates, which
meet at an angle of 127°. Each gate is 48 feet long, and weighs
seventy-five tons, the breadth being 8 feet in the middle, curving to 2
feet at the ends. There are six horizontal decks and four vertical
bulkheads. The depth at the heel-post is 22 feet, and at the
meeting-post 35 feet (see woodcut, fig. 19).
[Illustration: Fig. 19. Plymouth Dock Gates.
_Elevation._ _Section A. B._
_Plan._
_Scale of feet._]
In each gate is an air-chamber, the top of which is at half-tide level;
and its volume is such that when the gate is wholly immersed there is a
small downward pressure.[180]
Under each gate, near the meeting-post, is placed a wheel, which
supports part of the weight. This wheel is so arranged that it can be
easily removed for repair. The heel-posts are of cast iron, planed and
ground in place against the polished surface of the granite hollow
quoins so as to form a water-tight joint.
There are large scouring culverts behind the side walls of the entrance;
but for the purpose of regulating the level of the water in the dock,
and of discharging a large volume of water readily, without having to
overcome the friction of ordinary sluice valve faces, each gate is
furnished with a cylindrical valve, of the following description:--
From an opening in the side of the gate next the dock there is a large
curved pipe or sluice-way, which terminates inside the body of the gate,
with a circular horizontal orifice about 5 feet in diameter. The opening
is covered by a short length of vertical pipe of the same diameter,
reaching above high water, the bottom edge making a water-tight joint.
This pipe can be raised or lowered by a screw at the top of the gate.
When raised a short distance it allows the water from the dock to flow
out between the bottom of the movable pipe and the orifice of the
sluice-way into an isolated compartment of the gate, and to escape by an
opening provided in the outer face. The movable pipe is guided by
rollers, and from the construction the pressures on it are balanced.
The entrance to the graving dock, 80 feet wide, is closed by a pair of
gates of the same dimensions and construction as those of the entrance.
This dock is 380 feet long, 92 feet wide, and has a depth of 28 feet
over the sill.
* * * * *
The floating pier was erected in Mill-bay in 1852, to accommodate the
steam-shipping trade. It consists of a pontoon with a bridge leading to
it.
The pontoon is a large wrought-iron vessel of nearly rectangular
cross-section, 300 feet long, with 40 feet breadth of beam, and a depth
of 17½ feet. It is loaded so as to draw 10 feet of water, and is capable
of storing 4,000 tons of coals. To connect the pontoon with the shore
there is an iron bridge, working upon hinges, in two spans of 125 feet
each. The connection between the two spans was supported on a timber
pier, and was made so as to be movable vertically, and capable of being
adjusted by a crab and counterbalance weights. By means of this
arrangement a uniform gradient over the whole length of the bridge could
be obtained at any time of tide, for the convenience of heavily laden
carts passing to and from the pontoon.
_Briton Ferry Docks._
In 1846 a company was formed to establish docks in Baglan Bay at Briton
Ferry, near the mouth of the river Neath; but nothing was done until
1851, when the necessary powers were obtained under an Act of
Parliament. From the vicinity of the proposed docks to the South Wales
and Vale of Neath Railways, a large amount of trade was anticipated; and
in 1853 an Act was obtained for the South Wales Mineral Railway, which
was intended to terminate at the docks, and was expected to bring a
large traffic in coals and other minerals.
The dock works were begun soon afterwards, but the earthwork was not
completed, nor the construction of the gate commenced, until the year
1858. The docks were completed, after Mr. Brunel’s death, by Mr.
Brereton, and were formally opened on August 22, 1861.
They consist of an outer tidal basin of about 7½ acres, and an inner
floating basin of about 11 acres, with a depth of water of 27 feet at
spring tides, and 16 feet at neap tides. The two basins are connected by
a passage or entrance of 50 feet in width, with curved battering walls
and an invert, closed by a gate of a single leaf. An important advantage
of single gates is that the sill and quoins may be in one plane, and
that the troublesome and costly fitting of the hollow quoins is avoided.
The sill was laid 6 feet below what was then the low-water level, as it
was thought that future improvements might reduce the bar at the
entrance of the river Neath to that level. This has already been nearly
accomplished.[181] The total length of the docks is a little over half a
mile, and the average breadth is about 400 feet. They are connected with
the South Wales Railway by branch railways.
With the exception of the walls dividing the two basins near the
entrance gate, the sides of the dock are not constructed with masonry
quay walls, in the ordinary manner, but are formed in a very inexpensive
manner of slopes pitched with furnace slag, obtained from the copper
smelting works on the Neath river, with jetties at intervals for the
shipping. Besides being suitable for the soft clay in which the dock is
made, this plan is specially adapted for mineral traffic, as the work of
loading or discharging a cargo of minerals can only be properly carried
on at the point where fixed machinery is provided for the purpose. This
machinery may be placed as conveniently on projecting jetties as on a
dock wall. The traffic, which consists mainly of coals and metals, is
accommodated at the jetties, which are furnished with cranes for loading
and unloading the vessels employed in the metal and iron ore trade, and
with tipping-frames, which discharge the coals into the ships. These
cranes and tipping-frames are worked by hydraulic machinery.
In order to facilitate the entrance of vessels from the river Neath to
the tidal basin, and to protect it from the sea, two pier-heads were
built, one at each side of the basin at the point where it joins the
river. These piers are of timber piling and framework, filled in with
copper slag; the entrance between them is 300 feet wide. They were
constructed after Mr. Brunel’s death.
The gate is a wrought-iron buoyant gate, with five vertical partitions
or bulkheads and six decks. The length is 56 feet; the depth in the
middle is 31 feet 6 inches, and at the sides 26 feet 6 inches. The
breadth in the middle is 9 feet, and is curved to 2½ feet at the ends
(see woodcut, fig. 20).
[Illustration: Fig. 20. Briton Ferry Dock Gate.
_Elevation._ _Section A. B._
_Plan._
_Scale of feet._]
The air-chamber, which is similar to that of the Plymouth gates, is
placed so that the top is at the level of high-water neap tides, about
half-way up the gate.
There are two sluices at low-water level, each having an area of 8
square feet.
The entrance invert being subject to the influx of sand from the outer
basin, and to the deposit of coal rubbish dropped into the dock, Mr.
Brunel decided in this gate not to use wheels, but to make the hinge
and heel-post strong enough to carry the whole weight of the gate, even
if it were unsupported by the buoyancy of the air-chamber.
The heel-post is a massive piece of cast iron; the bottom part is bored
out, and into it is fitted a cast-iron cylindrical pin, 1 foot 6 inches
diameter and 7 feet 6 inches long. On this are ground discs of steel,
lubricated with oil, whereon the gate rests and turns. Thus the surfaces
exposed to friction are above the sand or grit at the bottom of the
dock. The lower end of the pin fits into a cast-iron socket fastened to
the masonry, and is prevented from turning round by being made
hexagonal. The sides of the hexagon have sufficient play to enable the
gate to adjust itself, when shut, to the masonry sill, so as to be
water-tight. The top of the heel-post works in a brass bush, 18 inches
diameter and 15 inches broad, enclosed in a massive wrought-iron collar,
which is strongly fastened by anchor chains to the masonry. After the
gate was completed the strength of the hinge was tested by moving the
gate before the water was admitted into the dock. The only resistance to
the motion of the gate is the slight friction at the hinge.
No coffer-dam was used in the construction of this work, but advantage
was taken of a large bank of slag and earth enclosing a portion of the
site of the dock. This was extended and raised, and a sea dam formed.
The dam was cut through when the works were completed, and a channel
dredged to the depth of 6 feet below low water.
_Brentford Dock._
In 1855 an Act was obtained for making a dock on the Thames at
Brentford, and a railway to join the Great Western Railway at Southall.
The dock has an area of about 3½ acres.
The works were begun in July 1856, and were completed, and the dock
opened, three years later.
The walls are founded in the London clay, which here underlies a bed of
gravel of some thickness; from this there was a considerable influx of
water.
The chief peculiarity of the dock is the form of construction adopted
for the sides. Piers of brickwork, 10 feet long and 2 feet 3 inches
thick, are placed at right angles to the sides of the dock at intervals
of 26 feet. The backs of these piers are connected by horizontal arches,
carried up with a curved batter. The piers are about 20 feet high, and
arches are turned upon them, which support the front part of the quay,
and meet the horizontal arches at the backs of the piers. Thus the sides
of the dock consist of a series of vaults, arched over at the top, and
also at the back towards the pressure of the earth.
[Illustration: Fig. 21. Brentford Dock Gate.
_Elevation._ _Section A. B._
_Plan._
_Scale of feet._]
The thickness of the horizontal arches which form the bulk of the wall
is only 3 feet, but these are so strengthened by the piers in front,
that a wall strong enough to resist the pressure of the earth behind it
was obtained by means of a very small quantity of brickwork.
Along one side of the dock the piers are 31 feet long, in order that
coal barges may lie with part of their length in the vaults between the
piers while their cargo is being put on board. By this arrangement the
barges have their longest dimension at right angles to the side of the
dock, and a much greater number can be accommodated than if each
occupied a space alongside the quay wall. The contents of the coal
trucks are tipped into the barges through sloping shoots.
The entrance has a clear width of 30 feet, and is closed by a single
wrought-iron buoyant gate, which, like the Bristol gates, is, when shut,
not quite at right angles to the entrance.
The gate is 33 feet long, 19 feet high, 2 feet 6 inches wide at the
middle, curved to 1 foot 6 inches at the sides, and weighs sixteen and a
half tons. It is divided into compartments by four decks and two
vertical bulkheads. The air-chamber occupies the whole space below one
of the decks, 7 feet 6 inches above the bottom (see woodcut, fig. 21);
and there are two sluices, each having an opening of 4 feet by 2 feet.
This gate, like that at Briton Ferry, has no wheel under it, the weight
being carried upon the pivot.
In order to avoid side strains upon the pivot and top collar, a
counterbalance arm is fastened on the top of the gate. This is formed of
two cast-iron girders, bolted together and enclosing weights between
them. The ends of these girders project beyond the heel-post over the
quay, as in canal lock gates, and carry the machinery by which the gate
is turned, as there are no crabs, chains, or chain rollers. Instead of
these, a cast-iron circular rack is fixed on the top of the masonry, in
which a pinion works, turned by gearing fixed to the end of the
counterbalance.
This gate turns with remarkable freedom, and the current of water
running into the dock on a spring tide opens it completely.
_Pier at Neyland, Milford Haven._
The South Wales Railway was originally intended to terminate at
Fishguard, on the north coast of Pembrokeshire, with the view of
securing a large quantity of Irish traffic, the distance across the
channel to the Irish coast at Wexford being only 60 miles, less than the
distance from Holyhead to Kingstown.
It was, however, ultimately decided to form a terminus, which would
accommodate the ordinary Irish traffic, and would not require such an
extensive outlay on harbour works as would have been necessary on the
northern coast.
With this object, the inlet or natural harbour of Milford Haven was
examined, and the South Wales Railway was carried to Neyland Point,
opposite Pembroke, where the position is sheltered, and there is deep
water at all times of tide for the largest vessels.
The pier at Neyland, or New Milford, which was made in 1857, consists of
a timber viaduct, with a pontoon at the end, 150 feet long and 42 feet
beam, loaded so as to draw about 7 feet. There is a depth of 16 feet
alongside it at low water, and it is connected with the shore by a
landing bridge. The pontoon is made of wrought iron, and has three
transverse and two longitudinal bulkheads. It is moored by chain cables,
which pass through two large hawse pipes, extending from the bottom
nearly up to the deck, with cast-iron mouthpieces at their lower ends.
The cables passing through these are anchored firmly to the ground at a
considerable distance from the pontoon.
The pontoon was intended to be the centre of several others, which were
to be moored in deeper water.
The rise of tide being sometimes as much as 25 feet, it was necessary
that the landing bridge should be of considerable length, in order that
there should be a moderate inclination at all times of tide. It is
accordingly made in one span of 205 feet. It consists of two plate-iron
side girders, of the uniform depth throughout of 14 feet, and width of 2
feet 6 inches. These are placed 12 feet 6 inches apart, the roadway
being between them. The ends of the girders which rest on the pontoon
are provided with cast-iron wheels, 1 foot 6 inches in diameter.
The pier has since been extended by additional pontoons, which were
those used in the floating of the Saltash Bridge.
CHAPTER XV.
_MISCELLANEOUS WORKS._
THE GREAT EXHIBITION OF 1851--THE CRYSTAL PALACE WATER TOWERS,
1853--POLYGONAL RIFLE, 1852--GUNNERY EXPERIMENTS, 1854--FLOATING
GUN-CARRIAGE, 1854--RENKIOI HOSPITAL BUILDINGS, 1855.
There are several matters of importance in which Mr. Brunel was engaged,
which could not under any system of classification be introduced into
the preceding chapters; these are therefore collected under one head of
‘miscellaneous works.’
The first of these is his connection with the Great Exhibition of 1851.
He was from the beginning one of the most zealous supporters of this
undertaking, and was appointed a member of the Committee of the Section
of Machinery, whose duty it was to classify the objects to be exhibited
in that department.
Upon the question of awarding prizes to exhibitors, Mr. Brunel held a
very decided opinion adverse to the plan ultimately adopted. In a letter
to the Chairman of the Committee, dated March 11, 1850, he writes:--
I am sorry to say that I am obliged to leave town to-night.
We are summoned to-morrow, it appears, on the subject of prizes.
Not being a member of the Commission, I have perhaps no right to
express an opinion upon a principle which seems to have been
adopted--that of giving prizes--but as applied to machinery I
suppose I may. I strongly disapprove of any prizes being offered in
our section.
1. I believe it is quite unnecessary.
2. I believe it will be impossible to define beforehand the
subjects for which any limited number and amount of prizes are to
be promised, the subjects are so indefinitely numerous; and like
the building, however large it may be made, will not be large
enough to hold all that is sent, so as regards the prizes, however
numerous the subjects, they may very likely not embrace the very
things which turn out to be most deserving.
3. I believe it will be impossible to distribute any limited number
of prizes with justice, and quite impossible to satisfy the public.
Two machines for the same purpose may be remarkable--one for its
ingenuity and beauty of workmanship, but of doubtful practical
economy in application; the other clumsy, and not well made, but
apparently likely to have the germs of much good--there are
thousands, or rather an infinity, of shades of degrees and
qualities of merit.
And lastly, I believe the prizes will be mischievous, as conferring
undue advantages in many cases upon a thing well displayed, and
well got up, and will be sought for and obtained for puffing
purposes. The opportunity of exhibition I believe will be quite
sufficient to induce all the competition we can desire.
I think money prizes quite a mistake, and medals or distinctions
pretty nearly as bad. I hope you hold the same views, but I send
you mine.
Mr. Brunel’s views found no favour at the time; but subsequent
experience has convinced those best able to form a sound judgment in the
matter, that ‘no prizes of any kind should be awarded’ in International
Exhibitions.[182]
Mr. Brunel was also a Member of the Building Committee; and he accepted
the office of Chairman and Reporter of the Jury for Class VII., on Civil
Engineering, Architecture, and Building Contrivances.
He took a very active part in the proceedings of the Building Committee.
Designs were invited, and two hundred and forty-five were sent in. None
of these were considered satisfactory by the Committee, and they
submitted to the Royal Commission a design of their own, the principal
feature of which was a dome 200 feet in diameter.
Mr. Brunel was responsible as a member of the Committee for the plans
prepared by them, and as regards the dome may be said to have designed
it himself, but he expressed strong objections to the substantial and
expensive buildings which it was proposed to erect in brickwork. His
idea was that the building should be in what he called the ‘railway shed
style;’ and he wished to produce effect rather by the construction of
the roofs, &c., than by any architectural elevation.
When, therefore, the plans of the Building Committee failed to meet with
public approval, and the late Sir Joseph Paxton submitted his well-known
design, Mr. Brunel gave it his cordial support, and defended it against
its detractors. He thus spoke of it in the report of the Jury of Class
VII.
As regards Mr. Paxton’s claim, amid the competition of the whole of
Europe, he proposed that mode and form of construction of building
which appeared on first sight, and has since proved to be, the best
adapted in every respect for the purpose for which it was intended.
The design possessed this merit of fitness for its object in a
singular manner. There was no startling novelty in any one point
which could lead astray the judgment of those who had to determine
upon the choice of plan, or which could in the first instance
obtain, still less permanently secure, the good opinion of the
public. As regards the form of outline, which is most simple,
several designs nearly resembling it had been submitted in the
general competition. As to the material, several proposals had been
previously made to cover the whole area to be enclosed with glass,
and iron would of necessity be employed for the framing; but in the
combination of form and materials, in the particular mode of
applying those materials, and in the adaptation of the forms to be
selected to their convenient use, as well as in the various details
by which the whole was rendered perfect, the design was entirely
distinct in character from all that had been proposed, and appeared
at once to have the one single merit of being exactly that which
was required for the purposes in view. The design as realised has
completely fulfilled every condition of utility.
The award of Council Medals (the highest prize given) was recommended
to Sir Joseph Paxton, and to the contractors, Messrs. Fox, Henderson and
Co.
In a later part of the report, in announcing the recommendation of a
Council Medal to His Royal Highness Prince Albert, for the model
dwelling houses which were erected near the Exhibition building, and
exhibited by the Prince, Mr. Brunel spoke in emphatic language of the
magnitude and importance of the results which would follow from the
introduction of improved dwellings for the working classes.[183]
* * * * *
When the Crystal Palace Company was formed in order to purchase the
Exhibition building and erect it, with additions, at Sydenham, Mr.
Brunel took a great interest in the project, and frequently went down to
examine the progress of the building and gardens, and the beautiful
architectural courts which were to be the chief attraction in the
interior of the Palace. The water towers, which are so conspicuous a
feature in the building, were designed by him.
The towers are 284 feet high, and carry near the top tanks 47 feet in
diameter and 38 feet high, holding 1,200 tons of water.
The foundations required great care in their construction. The tanks had
to be placed at a height of more than 200 feet, and the towers, which,
with their load, weighed fully 3,000 tons each, had to rest on the
sloping side of a clay hill. There was also the possibility that by the
bursting of a pipe a large quantity of water might be suddenly
discharged, and so cause a slip in the surrounding ground. Mr. Brunel
carried the foundations down to a considerable depth, forming a large
base of Portland cement concrete, and placing on it a cone of brickwork
in cement, rising up to the ground level. The towers are twelve-sided,
with two hollow cast-iron columns at each angle. The height of the
building below the tanks is divided into ten stories, and at each floor
there is a strong wrought-iron diaphragm, or shelf, 5 feet wide. The
columns are also connected by strong diagonal bracing in the sides of
the tower.
The tanks are made of wrought iron, and the water pipes are placed in
the interior of the tower. Mr. Brunel did not think it would be prudent
to form any of the columns of the towers into pipes, lest the expansion
due to the temperature of the water should cause unequal support to be
given to the tanks.
In July 1855, the pipes were proved, and the towers were completed
shortly afterwards.
* * * * *
The remainder of this chapter will relate to matters which have but
little in common with the subjects of the earlier part of it; but the
change is hardly less marked than that which took place in the nature of
the questions which occupied public attention within a few years of the
close of the Great Exhibition.
_Polygonal Rifle._
In October 1852, Mr. Brunel consulted Mr. Westley Richards, of
Birmingham, as to the manufacture of a rifle ‘for the purpose of
determining whether there was anything in a crotchet he had upon the
subject.’ The rifle was made by Mr. Westley Richards according to Mr.
Brunel’s directions, and finished in May 1854. Many experiments were
tried with it, at Birmingham and at Manchester, in the spring of 1855,
and afterwards at Woolwich; and its performances obtained great
notoriety.
The history of this rifle, and the objects Mr. Brunel had in view in its
design, will be understood from the following letters to Mr. Westley
Richards:--
I.
October 25, 1852.
I have long wanted to try an experiment with a rifle, for the
purpose of determining whether there is anything in a crotchet I
have upon the subject, but I have been deterred from attempting it
from the feeling that in these abominable patenting days (I hate
patents) the chances were, that if, in the progress of my
experiments, any new result, good or bad, were observed, or a
workman should think he _saw_ something, a patent would be taken
over my head, and, to say the least, I should be stopped in
pursuing my own investigation, as has happened to me more than
once.
I have also been deterred by my not knowing whether the existing
machinery for rifling barrels would enable me to obtain an
increasing or varying twist from one end of the barrel to the
other, as this would be necessary to make the experiment, and I
should not care to incur the expense of a machine on purpose. My
introduction to you, through our mutual friend Whateley, induces me
to make the enquiry whether your apparatus or mode of rifling
enables you to give such a twist, and if so, whether you could and
would make me a barrel. If so, I will trouble you with an
explanation of my scheme, as I should have no secrets with you.
II.
February 7, 1853.
I take this opportunity of mentioning again the subject I once
wrote or spoke to you about. I want a rifle barrel made octagon
shaped inside, the octagon having a twist rather more than usual,
and an increasing twist, say twice as much at the mouth of the
piece as at the breech. Can you make me such a barrel for an
experiment? I will explain to you the object when we meet, as it
can only be done _viva voce_.
III.
[The following letter was written to Mr. Westley Richards in answer
to a request that Mr. Brunel would permit him to obtain a license
from Mr. (now Sir Joseph) Whitworth to make rifles of a polygonal
shape. Mr. Whitworth had obtained a patent for improvements in
cannons, guns, and fire-arms, in February 1855, and in his complete
specification, dated May 30, 1855, he had for the first time
claimed--
Firstly, the several combinations of parts forming, when put
together, the barrels of ordnance, or fire-arms, having a polygonal
spiral shape. Secondly, the use of the spirally-shaped segments.
Thirdly, the adoption of the polygonal spiral for rifled ordnance
and fire-arms. Fourthly, the combination of parts forming the
breech-loading apparatus.]
November 26, 1858.
I am obliged to you for your communication on the subject of the
octagon gun, and in acknowledging your courtesy and gentlemanly
feeling I would add that it is only what I always felt I could rely
upon from you.
I beg you will not hesitate to take out a license from Mr.
Whitworth for octagon guns (if, as a matter of business, you think
it convenient to do so) on account of any prior claim which you may
know I could set up, and if you get a license for a nominal
consideration, as I understand you can, of course as a man of
business you should do so. I have no intention of interfering with
Mr. Whitworth’s patent, even to indulge the feeling I have against
all patents and protective laws, which I consider have become the
curse of the day, and the sources of the greatest injury to
inventors and manufacturers, and still more to the public; and I
should also be very sorry even to annoy my friend Mr. Whitworth
merely for the sake of showing that I had previously made the gun
(at least you made it for me), and I believe others have preceded
me, which he has patented; and I assure you that I shall not
consider your taking out a license as in any way a denial of this
fact, of which you are cognisant.
I have never seen Whitworth’s patent; what is it exactly that he
does patent? It cannot be merely the polygon, because, even if
nobody had preceded me, that would have been already a copy of
mine, which not only was made before he began his investigation,
but was lent by me, at your request, to him, I think before his
patent. My rifle is, I am told, doing quite wonders at Woolwich,
and I begin to think there must be something in the principle which
I intended to introduce into it, and which is totally different
from what I understood to be Whitworth’s. I sought to use a
comparatively loose ball, but which I thought would centre itself,
both in position and direction, to the axis of the barrel by the
peculiar action of a polygon within a polygon acted upon by an
increasing pitch, and it really seems from the results as if my
theory was correct.[184]
_Gunnery Experiments._
In 1854 Mr. Brunel took up warmly the question of improvement in large
guns, which was then attracting the attention of several scientific men.
The friendship which had for some years previously existed between him
and Mr. (now Sir William) Armstrong, of Newcastle-on-Tyne, gave Mr.
Brunel opportunities for discussing these matters, with a view to their
being carried into practical effect.
The following extracts from a letter written by Mr. Brunel, in April
1855, to Mr. James Nasmyth, explain generally his opinions at that time
upon the construction of large guns:--
From what I have observed of the operation of fractures under
_sudden_, quick-acting forces--such as bursting of guns, and
fractures under blows, as in our railway smashes--I have arrived
deliberately by observation at the conclusion, which every
mechanical-minded man arrives at more or less by intuition, that
homogeneity and equality of tension and of elasticity in the parts
are necessary for strength to resist a violent strain applied
suddenly in its full force, which I will call a blow. My
impression, from the result of observation, is, that this operates
much more than is generally assumed.
If you suppose a bar, say an axle of uniform section and uniform
quality in every respect, it will bear bending into extraordinary
forms even by a blow; and if you assume that portions of it become
more tenacious and stronger, but remain equally elastic, the
ultimate strength of this bar will not, I think, be materially
increased or diminished; but if you suppose the elasticity of these
portions either increased or diminished, I believe the ultimate
strength of the bar under a blow is diminished. In like manner, I
imagine that in the section of a gun barrel, if portions are more
or less elastic than others, or at all different in their
character, not only many points of fracture may be determined on,
but that the whole may be rendered much less able to resist the
violent explosion. The strain produced by the explosion and the
plane of fracture is almost certain to be in a plane passing
through the longitudinal axis, and therefore I had assumed that one
would avoid as much as possible having any variation of quality
which fagotting must produce to some extent in planes in this
direction. To attain this end, I had endeavoured to scheme some way
of welding up ‘cheeses’ or discs, which might be hammered up
splendidly homogeneous of the full diameter and of a considerable
thickness, and I wish that you would scheme the best way of welding
them together. I should suppose that the centre surface might be
welded, and wedges welded in all round, or some other mode devised,
bearing in mind that the strain in any plane transverse to the axis
is small, only that arising from the recoil of the breech and the
friction of the shot.
I have also an impression that something harder than ordinary
wrought iron is wanted for the inner surface to resist the
explosion. This you might give probably in fagotting up. I am
trying the effect--as much for the amusement of the thing as with
any great expectation--of a cylinder of hardish material wrapped
round with iron wire, laid on with a certain amount of tension
proportioned to the diameter. Such a barrel ought to be
strong--whether practically successful is another thing.
The scheme of making a gun with the barrel wrapped round with wire,
which is referred to in this letter, was one which Mr. Brunel and Mr.
Armstrong were very desirous of making the subject of actual experiment.
Whether or not it would under their hands have become practically
successful, could not be ascertained, as they were obliged to abandon
the project, in consequence of the wire covering being patented, in May
1855, by Mr. Longridge.
The following letter to Mr. Armstrong relates to the same subject, and
is interesting not only as showing Mr. Brunel’s correct appreciation of
a principle which is the essence of the coil system of constructing
guns, but as further illustrating his objections to the patent laws:--
June 8, 1855.
Have you ever done anything towards my experiment of the wire gun?
I have been anxious for some time past to learn about it, but have
waited to see you; to-day I learn that Longridge is taking out a
patent for it. I daresay it is his own idea, and I only regret it,
as I suppose it will now prevent my pursuing it; and I think it
likely that with your assistance we should have succeeded in making
at least as good a gun as he will. The principle I am disposed to
think good; the success would depend upon the practical
application, and but for these patents, the more competitors the
better for the public. As it is, competition is destroyed. Let me
know if you had done anything. Pray let me know also what you are
doing about your own, in which I feel equally interested.
Mr. Brunel had also considered the advantages of making the bore of the
gun polygonal, with a projectile shaped to fit it. He had a portion of
cannon tube and a projectile made by Mr. Armstrong in the beginning of
1855, but he did not himself pursue the question further.
Indeed, after the middle of the year 1856, when the works of the ‘Great
Eastern’ steam-ship began to occupy a large portion of his time, Mr.
Brunel was unable any longer to take part in gunnery investigations; but
he watched with unabated interest the proceedings of those friends who
have continued their experiments, with the great practical success of
which he lived to see only the beginning.
_Floating Gun-Carriage._
The plan of a gun-boat, or, as it would be more correctly called, a
floating gun-carriage, which Mr. Brunel designed for an attack on
Cronstadt and other Baltic forts during the Russian war, is clearly
described in the following memorandum, which he drew up for the
information of the Admiralty:--
December 20, 1855.
The principle is simply the fixing a very heavy gun in a floating
shot-proof chamber or casemate, exposing the smallest possible
surface; that surface to be of such a form as to be struck by shot
only at a very oblique angle; and the gun being a fixture, with the
means only of elevating and depressing to an extent of 10 or 12
degrees, but with no lateral motion, the port or embrasure need be
only of the size of the muzzle of the gun, so that the gun, the men
working the gun, and everything on board will be perfectly
protected.
The gun will be directed by elevating the breech, and by slewing
the vessel slightly and slowly backwards and forwards across the
line of aim, by means afterwards explained.
The men loading the gun will simply load as quickly as they can,
and when the gun is loaded push out a trigger.
The governor or person directing the gun will stand behind the hood
or chamber, looking direct at the object through a telescope of low
power, fixed horizontally in the axis of the vessel, and made to
move vertically parallel with the axis of the gun, and mounted with
reflectors; so that both telescope and man are completely under
cover, and he, keeping the vessel truly in range and the elevation
correct, will only touch the trigger whenever his line of sight
crosses the object.
The vessel will carry a small engine, of power sufficient to drive
it for a short time at a good speed, say eight or nine knots, and
at other times to keep up a small forward motion to counteract the
recoil, and to keep the vessel’s head moving a few degrees right
and left across the line of range.
A sufficient portion of the vessel to contain and to float the gun,
ammunition, and engine, will be shot-proof.
A fore-body and after-body, the top of which will be _à
fleur-d’eau_, or a few inches under water, will be added, to give
such a form of entrance and run as will admit of the vessel
attaining the speed mentioned; but these parts will be mere shells,
and may be full of water, and if damaged by shot will not affect
the buoyancy of the float, besides which, not being above the
surface of the water, they cannot be much exposed to injury.
The mode of propelling may be by a screw, but I prefer the ‘jet,’
which, whether an economical mode of propelling or not, is a
sufficiently good one for this purpose, and exposes _nothing_
whatever to be injured by shot.[185]
Whether propelled by jet or not, I should have two small lateral
jets for directing the vessel, such jets being governed by two
cocks handled by the gunner.
Such a mode of directing the aim by a man under cover looking
through a telescope, with one hand directing the gun and the other
on the trigger, will admit of an almost unlimited degree of
accuracy.
The gun being in a perfectly shot-proof casemate, machinery may be
adapted to expedite the loading of the gun; and it is not difficult
to make a mechanical arrangement by which the shot and cartridge
shall be lifted up to the gun, inserted, and rammed home, at a rate
far exceeding anything that can now be done by hand; and as the
weight and clumsiness of the gun, the carriage, and machinery are
of no object, I think I can make a breech-loading gun capable of
carrying 12-inch solid shot with a full charge, which may be loaded
and discharged at the rate of two or three per minute; but the
principle of mounting a gun in such a float is equally applicable
to a common gun, which might still be loaded mechanically.
A few loopholes may be provided through which a fire could be kept
up from a couple of heavy swivel rifles, carrying, say 6-oz. shot,
which would pierce any mantelets or other cover likely next year to
be provided against ordinary rifles.
A battery, say of twelve such guns, should probably have also two,
or perhaps three, shot-proof vessels of about the same size without
guns, but pierced with a longitudinal fin or ridge, like a wall,
standing, say 10 feet above the water, and 50 or 60 feet long,
strong enough to stand the direct blow of heavy shot at long range,
or the oblique blow of the same shot at short range, and which
could be placed as screens or traverses to cover the flanks of the
battery against distant shot. Against vertical fire I cannot
suggest any defence: the point of attack must be selected to avoid
it.
The covering vessels may be provided also with loop-holes for heavy
swivels.
There should also be two or three small and comparatively light,
but shot-proof vessels, to run in and bring out a disabled
gun-boat.
These last-named auxiliary unarmed boats form an essential part of
the system.
In all probability the enemy have by this time thrown stones and
other obstacles, and placed infernal machines round the detached
fort, to impede a close approach. They cannot, however, have
covered a very large surface, so that, with some previous sounding,
an approach may be found and a position taken up.
The auxiliary boats should therefore have strong bottoms under the
engine-room, and the rest of the body be so subdivided into
compartments that they would be proof against serious damage from
rocks and infernal machines, and be able to run in under fire and
ascertain if obstructions exist, and find the channel if they do.
A battery of such guns could be placed at various points out of
range, say at 3,000 yards, at which distance they would hardly
attract attention by daylight, and would not be visible in the
twilight of night, and could then be concentrated in a few minutes
at the point selected for attack within safe breeching distance,
say 250 yards; and, if twenty-four shot per minute, of 200 lbs. to
250 lbs. each, thrown with a full charge at 250 yards, can be
directed against a small surface of any stone wall yet built (which
is pierced with embrasures), the effect ought to be great and
rapid. I believe, moreover, that the means of directing the aim
will be so effective that if the embrasures can be seen a shell or
shot may always be sent in with certainty at 250 yards, and the
enemy’s guns dismounted.
Such vessels can rapidly change their position, retreat or advance,
be replaced by fresh ones, or withdrawn altogether.
The means of transport of such vessels to the seat of war, although
a secondary consideration, has been considered.
They might easily be placed in an outer shell of iron of a good
form, which could be rigged complete, and so constructed as to give
up its burden when arrived in the seas where it is to act--in fact,
a ship of the class of small screw colliers, made to open at the
bows and its contents floated out ready for action; but the
gun-boat itself, when lightened of ammunition, and the gun lowered
to the bottom as ballast, and fitted up with bulwarks, and a light
movable iron chamber, forming a water-tight forecastle-deck
reaching back, say 30 feet, and schooner-rigged, will, I undertake
to say, make a very fair sea boat. Probably no compasses could be
‘corrected’ to be trusted to in such a mass of iron, but a compass
fixed to the mizenmast, say at 30 feet from the deck, would be all
that could be required.
Immediately abaft the hood or gun-chamber there would be a space
under cover from shot where a companion and skylight could be
fitted up when at sea, and through which light and air could be
obtained at all times when fitted for service.
The funnel, if ever used when the vessel is not in action, would be
removed for fighting, and the steam and smoke ejected through an
oblique aperture right aft.
The only point to be determined by experiment is whether a moderate
thickness of iron of the best quality will stand heavy shot at
short range striking very obliquely, say at the worst at an angle
of 30 degrees.
By the form of the proposed vessel, however, when placed in
position at 250 yards of any of the Cronstadt forts, it could not
be struck at 30 degrees, and probably 99 out of 100 shots that hit
would graze at an angle of 10 to 20 degrees.
A small part only round the port, or what may be more correctly
termed the muzzle-hole, could be struck with a direct blow.
There is every reason to believe that slabs of iron of good quality
of 4 inches thick would stand against such grazing, provided they
are put together without being weakened by holes and with some
other precautions, and that sound forgings of 10 or 12 inches
thick, if of sufficient weight in a single piece, would stand the
direct blow. I do not believe that less than this would be safe
against 68-lb., or, as we must expect to meet with, 120-lb. shot at
short range, even when struck obliquely, and this thickness can be
applied without requiring, with the gun ammunition, &c., more than
6 feet 9 inches, say 7 feet draught of water.
Another inch of thickness would require another foot of draught;
but if it has been ascertained that the charts are correct, there
would appear to be 10 to 15 feet of water close up to the principal
detached forts, and it would be an immense advantage to take 9 feet
draught of water, and have an unquestionably invulnerable skin.
If it were considered desirable to construct such a battery, it is
now barely possible to do it in time for the coming season; but if
possible, it could only be rendered so by ascertaining exactly the
dimension and form of iron that each of the large makers could turn
out with their present tools, and according to their present
experience and habits, and to design the details to suit their
existing means, sacrificing probably much that would render the
result more perfect for the sake of rendering it possible to obtain
anything in time. No doubt promises and even contracts could easily
be obtained for making anything in any given time, and zealous and
honest efforts afterwards made to effect what had been undertaken;
but if the slightest attempt is made that involves new tools or new
practices, promises and contracts will not effect impossibilities,
and the probability is that the short time still available will be
lost.
While all the preparations shall be made on the assumption that the
result is attainable and will be successful, trials must be made,
without loss of time, on the several points to be determined--as to
the resistance of the iron, &c. If they fail, the expense incurred
up to that time in preparing for the whole work will not have been
great. If they succeed, it is just possible that by great exertions
but, above all, by judicious and methodical plans of proceeding, a
complete battery might be launched ready for service in five
months.
Lastly, I should observe that although the main feature of the plan
is the resisting the effects of the enemy’s shot by always exposing
an oblique surface, yet the chances of fatal damage would be small
if such vessels were to run the gauntlet, at night, through the
deep channel, and get into the waters east of Cronstadt. Or if this
is very desirable, as I should think it must be, nothing is easier
than to lift the whole flotilla over the shoal water and launch
them into the deep water beyond.
Mr. Brunel had matured these plans in September 1854, and they were then
brought under the notice of the Admiralty; but no steps were taken to
test the practicability of the scheme.
He was, however, induced to make a further representation to the
Admiralty in the following July. He wrote,--
Having endeavoured ineffectually several times at the commencement
of the war to impress upon members of the Government the great
advantages that might be derived from the use of iron floating
batteries or gun-boats, if properly constructed, I made another
effort at the close of the last year’s campaign, but early enough
to have allowed of the construction of what I proposed before the
opening of the Baltic in the present year, and caused my plans to
be submitted to the Admiralty through a friend. They were not
approved, and I should judge from the answer I received that they
were not understood, and I was never applied to for an explanation.
I had no object in view but the public good, and I therefore kept
the idea, such as it was, unpublished, believing the principle to
be sound and good, and that the day would come when it might be
usefully applied, and the more usefully to this country if not
previously publicly discussed.
I have no other object to serve now; but after the clear proof that
I was correct in the opinion I shared with so many other persons of
the entire inability of any of the present floating ships, boats,
or war engines to cope with any moderately constructed and
well-armed land battery, I think it right once more, and this time
more formally, to urge upon Government the consideration of the
construction of armaments mechanically constructed and properly
fitted for the special object. I beg to say that I do not mean a
consideration in the ordinary mode, by the able and practical, but
still executive officers of departments, whether engineers or
ship-builders, because I believe that I must be myself, from my
practical experience in this particular branch, at least as
competent, if not more so, to judge in questions of mechanical
construction, whether it be the forging or casting of a gun of
large dimensions, or the construction of a vessel fit for
navigation and capable of resisting shot, or the best mode of
propelling such a vessel--on all which branches I have had much and
tolerably successful practice; but I ask on public grounds for the
deliberate consideration by men of judgment and experience in the
military branch of the subject, such as the attack upon a fortified
place, of which I cannot pretend to be a competent judge, and by
men in a position to be able to express freely their independent
opinions of the advantages that might be attained by the principle
I propose, if capable of being successfully carried out.
Although the want of efficient gun-boats was then severely felt, this
letter appears to have produced no effect upon the Board of Admiralty.
But the friend who had originally brought the matter under the notice of
the Board took the bold step of writing to Lord Palmerston, and
acquainting him with what had passed.
Lord Palmerston at once saw the importance of investigating the subject,
and sent for Mr. Brunel, who explained the plans to him. Lord Palmerston
then asked him to see the officials at the Admiralty. Mr. Brunel did so;
but great delay followed. It was, however, unimportant, as hostilities
soon afterwards terminated, and there was no further need of gun-boats,
good or bad.
This project did not exist only in the outline in which it is described
in the memorandum given above. Mr. Brunel had worked out all the
calculations of displacement, &c., and had made designs and models for
the boat and its various appliances, and had been for some months in
constant communication with Mr. W. G. Armstrong upon the form and
construction of the gun.
* * * * *
This will be a fitting place to mention that in 1855 Captain Cowper
Coles, C.B., showed Mr. Brunel the designs for his shot-proof raft, the
principle of which was afterwards developed in the turret ship. Mr.
Brunel gave Captain Coles the benefit of his advice on the various
questions involved, and allowed him to use the services of his principal
draughtsman, and to have the drawings got out in his office without
expense.
Captain Coles, in a lecture which he delivered at the United Service
Institution on June 29, 1860, warmly acknowledged the obligations he was
under to Mr. Brunel for this act of kindness and generosity, and said
that it had greatly encouraged him to persevere in bringing his plans
into public notice.
_Renkioi Hospital._
In February 1855, after the first winter of the allied armies in the
Crimea, Mr. Brunel was asked by the War Department to undertake the
design and construction of hospital buildings for the East.
He replied (on the same day that he received this application, February
16) that his ‘time and best exertions would be, without any limitations,
entirely at the service of Government.’
He was accordingly appointed as engineer, and proceeded to design and
superintend the manufacture of the required buildings and all their
internal arrangements. They were sent out under his supervision, and
erected at Renkioi, on the Dardanelles. All use for the buildings was
ended with the conclusion of peace; but, for the seven months during
which they were occupied, they added much to the comfort of more than
thirteen hundred sick and wounded soldiers.
Many of the special arrangements adopted at Mr. Brunel’s suggestion have
been since brought into general use; and the success of these buildings
was, to a considerable extent, influential in leading the Americans to
construct similar hospitals during their civil war. These are now (1870)
being copied in the German armies.
* * * * *
The history of the Renkioi hospital buildings is a striking instance of
the zeal with which Mr. Brunel entered into any undertaking which had a
claim upon his assistance, of the varied experience and fertility of
invention which he could bring to bear upon any subject, however remote
it might seem to be from his ordinary occupations, and of the minute
personal attention he was accustomed to give to every detail, as the
only certain means of ensuring success.
Mr. Brunel entered upon his duties on February 16, and reported to the
War Office on March 5 that he had not lost any time nor spared any
exertion or any means in his power to forward the important business he
had undertaken. He stated that he availed himself freely of the advice
and assistance of all persons to whom he could apply with any prospect
of advantage; and he added, ‘It is most gratifying to be able to state
that from everybody I have received the most zealous and cordial
assistance, and found it sufficient to mention the object of my
enquiries to obtain immediately every assistance I could possibly
require.’
An experimental ward was erected a few days afterwards on the premises
of the Great Western Railway at Paddington, and was carefully criticised
by competent persons; and, the plans having been approved of,
specifications were made, with drawings of the various parts, and
tenders were invited for the construction of the buildings.
The following paper gives a description of the buildings, and was
written by Mr. Brunel in order to satisfy the curiosity of his
friends:[l]--
March 1855.
The conditions that it was considered necessary to lay down in
designing these buildings were,--
First. That they should be capable of adapting themselves to any
plot of ground that might be selected, whatever its form, level, or
inclination, within reasonable limits.
Secondly. That each set of buildings should be capable of being
easily extended from one holding 500 patients to one for 1,000 or
1,500, or whatever might be the limit which sanitary or other
conditions might prescribe.
Thirdly. That when erected they might be sure to contain every
comfort which it would be possible under the circumstances to
afford. And--
Fourthly. That they should be very portable, and of the cheapest
construction.
The mode in which it has been sought to comply with these
conditions is as follows:--[186]
The whole hospital will consist of a number of separate buildings,
each sufficiently large to admit of the most economical
construction, but otherwise small and compact enough to be easily
placed on ground with a considerable slope, without the necessity
of placing the floor of any part below the level of the ground, or
of having any considerable height of foundation to carry up under
any other part.
These separate buildings have been made all of the same size and
shape; so that, with an indefinite length of open corridor to
connect the various parts, they may be arranged in any form, to
suit the levels and shape of the ground.
Each building, except those designed for stores and general
purposes, is made to contain in itself all that is absolutely
essential for an independent hospital ward-room; so that, by the
lengthening of the corridors, and the addition of any number of
these buildings, the hospital may be extended to any degree.
To ensure the necessary comforts, and particularly to provide
against the contingency of any cargo of materials not arriving on
the spot in time, each building contains within itself two
ward-rooms, one nurse’s room, a small store-room, bath-room, and
surgery, water-closets, lavatories, and ventilating apparatus.
The ward-room is made wide enough and high enough to ensure a good
space of air to each bed, even if these should be unduly crowded.
Each building contains two ward-rooms, intended for twenty-six beds
each, which is found in practice to be a size of room admitting of
proper control and supervision.
With respect to closets and lavatories, after examining and
considering everything that has been done, both in hospitals of the
best description and poor-houses of the cheapest construction, it
was found that the requisite security for cleanliness and the
greatest amount of economy of labour, and of consumption of water,
could be obtained by a cheap description of water-closet designed
for the purpose; and with the same object of diminishing the amount
of labour and the waste of water, and securing cleanliness without
depending upon the constant attention of assistants, fixed basins
for lavatories and mechanical appliances for supplying and drawing
off water were adopted.
As a protection against heat, experience in hot climates and
experiments made expressly for the purpose satisfactorily proved
that a covering of extremely thin and highly polished tin, which
reflects all direct rays of heat, was the cheapest, lightest, and
most effective protection, and every piece of woodwork not covered
with tin is to be whitewashed externally. Internally the lime-wash
has a slight tint of colour, to take off the glare.[187]
To secure ventilation in a hot climate with low buildings extending
over a large area, and therefore incapable of being connected with
any general system of ventilation, it was considered that _forcing
in_ fresh air by a small mechanical apparatus attached to each
building would be the only effective means. Each ward-room is
therefore furnished with a small fan, or rotatory air-pump, which,
easily worked by one man, is found capable of supplying 1,000 to
1,500 cubic feet of air per minute, or 20 to 30 feet for each
patient. This air is conveyed along the centre of the floors of
each ward-room, and rising up under foot-boards placed under the
tables, is found to flow over the floor to every part of the room.
Besides this mechanical supply of air, opening windows are provided
along the whole length of the eaves, and spaces left immediately
beneath the roof at the two gables, amply sufficient together to
ventilate the rooms thoroughly if any breezes are stirring, without
the help of the fan.
The light is admitted by a long range of narrow windows,
immediately under the eaves, which protect them from the direct
rays of the sun. These windows open, and are provided with shutters
inside, which exclude the light, but admit the air.
By forcing the air into the room, instead of drawing it out, the
entrance of bad air from the closets, drains, or any surrounding
nuisances is prevented. The fan is placed at the opposite end to
the closets and drains; and all the fans being in the open
corridor, the workmen can be seen by a single sentry, and kept to
their work.
The buildings, as now constructed, are adapted to protect the
interior from external heat. Should winter come while they are
still in use, the framework is adapted to receive an internal
lining of boarding, and the interstices can be filled with a
non-conductor.
Two buildings, of the same form and dimensions, are fitted up with
every convenience as store-rooms and apothecaries’ dispensaries.
An iron kitchen, slightly detached from the wooden buildings,
fitted up with every contrivance capable of cooking for from 500 to
1,000 patients, is attached.
A similar building of iron is fitted up with all the machinery
lately introduced in the baths and washhouses of London for washing
and drying in the minimum space, and with the least amount of
labour.
If an aggregate of buildings should be placed in one spot for more
than 1,000 patients, a second kitchen would be added, but the
single washhouse would be sufficient.
With each set of buildings is sent a pumping apparatus, a small
general reservoir, and a sufficient length of main, with all its
branches, to supply water to every detached building; and all the
pipes and branches are of such construction as to admit of being
put together without any soldering or cement. A system of drains
is provided, formed of wooden trunks properly prepared, and of
sufficient extent to form a complete and perfect system of drainage
from every building to a safe distance from the general
hospital.[188]
A number of small buildings, intended to be detached from the main
body, are provided for residences for the officers and servants of
the establishment, and for a small detachment of soldiers. A
slaughter-house and store-yard and some other appurtenances are
also provided, the extent of which depends on the circumstances of
each case.
The construction of each building has been studied with very great
care, so as to secure the minimum amount of material, the least
possible amount of work in construction or erection, and the means
of arranging all the parts in separate packages capable each of
being carried by two men; and the result is that each building is
the cheapest and lightest that has yet been constructed in
proportion to the area covered.
For the transport of the materials to the spot selected, two
sailing-vessels and three steamboats, capable of carrying one
hospital for 1,000 men, which is the first about to be sent out,
have been secured. In each vessel is sent a certain number of
complete buildings, with every detail, including their proportion
of water-pipes and drains, closets, lavatories, baths, &c., and a
small amount of surplus material and tools; and in each of two
separate vessels are sent a set of pumps and mains, and a kitchen
and washhouse. So that by no accident, mistake, or confusion, short
of the loss of several of the ships, can there fail to be a certain
amount of hospital accommodation, provided with every comfort and
essential.
The peculiar circumstances under which these establishments are
likely to be placed have required not only peculiarities of
construction, but these, in turn, have required numerous provisions
and details specially designed for the case.
As all the buildings, except the kitchen and washhouse, are
entirely constructed of wood, it is considered essential that no
stove or fire-place of any description should be allowed in any
part, except in the iron buildings; in these there is provision for
an ample supply of hot water, but each ward-building is provided
with a small boiler, heated by candles, which by experiment have
been found amply sufficient for all that can be required. Candles
are to be used exclusively for lighting, and lamps and lanterns
have been constructed for the purpose.
A proper supply of fire-engines is provided, and other
precautionary measures are adopted against fire.
The condition of portability requiring that the walls and roofs
should be of the thinnest and slightest possible construction,
protection against heat has been provided for in the manner before
referred to, and good ventilation secured by mechanical means. But,
in addition to this, there is a very simple provision made for
passing the air over a considerable extent of water surface; which
would not only cool it, but diminish the effect of excessive
dryness, which is said to be occasionally in this climate more
oppressive than even the temperature.
As the space in the wards is very liable to be encroached upon, and
the beds crowded, portable baths have been designed, into which the
more helpless patients can be lifted, and lowered, on a frame or
sack, without requiring space for assistants to stand around, or
with the bath placed only at the foot of the bed.
The kitchen and laundry have each required many special
contrivances.
The instructions given to Mr. Brunton, the engineer, who has been
sent out for the purpose of erecting these buildings, are, to
commence by determining on his plan of arrangement to suit the
peculiarities of the ground, and then to construct the complete
system of drainage and to lay on the water supply before the
buildings are rendered capable of receiving patients; and all the
arrangements of the details are designed with the view of
obtaining, as the first conditions, a perfect system of drainage, a
good supply of water, free ventilation, and the most perfect
cleanliness, quite independent of labour and of the continued
attention of assistants; these conditions being assumed as
essentials, preceding even the mere covering in of space and
providing shelter for patients.
The cost of these buildings, delivered ready for shipment, will be
from 18_l._ to 22_l._ per bed, allowing 1,000 cubic feet of space
in each ward-room to each bed. If pressing emergency should lead to
the beds being placed closer, and fifty per cent. more patients
should be introduced, it is believed that the perfect system of
ventilation which is secured would render these hospitals very
superior to any now in use for the army.
Of the cost above named, about 12_l._ per bed is that due to the
ward-rooms themselves, with all their conveniences attached, and
the rest arises from the cost of the store-rooms, kitchen,
machinery, residences, and appurtenances.
The cargo space required for their conveyance is about a ton and a
half to a ton and three-quarters measurement per bed.
As the buildings were completed the work of transport was commenced; and
twenty-three steamers and sailing-vessels were despatched, containing
altogether about 11,500 tons measurement of materials and stores. The
first vessel arrived out on May 7, 1855, and the last on December 5, in
the same year.
Meanwhile the important question of the site for the hospital buildings
was being determined by Dr. Parkes, the Medical Superintendent, with the
assistance of Mr. Brunton, who was in constant communication with Mr.
Brunel on the subject.
After visiting various places, Dr. Parkes finally selected a spot near
the village of Renkioi, on the Dardanelles. In a report which he
addressed to the Secretary of State for War upon the formation and
general management of the hospital, he thus describes ‘the nature of the
site, and the means which were used in the formation of the hospital:’--
The piece of land on which the hospital was placed was a shelving
bank of a light, porous, sandy soil, resting on marl; it contained
about 270 acres, stretched tongue-like into the waters of the
Dardanelles, and was bounded inland by a low range of sandstone
hills, which were themselves backed by rather lofty ranges of
oolitic limestone, intersected by deep ravines. The tongue of land
formed two bays, north and south, in both of which was good
anchorage for ships, and as the wind blew almost always up or down
the Dardanelles, i.e. from the north-east or south-west, one or
other of these bays was comparatively calm in all winds except
those which came infrequently from the west.
The position of the spot was on the Asiatic coast, nine miles from
the mouth of the Dardanelles, in lat. 40° 2′, long. 26° 21′. It was
the site of the port of an old Greek city, the ancient Ophrynium.
The extreme point of this tongue of land was about 10 feet above
the sea, but from this point it rose regularly and gradually to
about 100 feet above the sea. An admirable fall was thus given for
drainage, and so gradual was the rise that the wooden houses were
placed on the ground without terracing or excavation, whereby very
great expense was saved. The extreme length from the point to a
spot too steep for the erection of houses was about half a mile,
and we were enabled thus to place down the centre of the tongue of
land no less than thirty-four houses, capable of holding 1,500
sick, in one long line on either side of the central corridor, an
arrangement which facilitated very greatly the laying of both
water-pipes and drain-tubes. In fact, we were able to carry out the
plan which Mr. Brunel had suggested as the best.
There was enough space on the tongue of land, on either side of
this long central line, for two shorter parallel lines of seventeen
houses each. These two lines were placed one to the north, and the
other to the south of the large central hospital. Each was capable
of containing 750 men, and one of them to the north was nearly
completed when the declaration of peace put a stop to the works.
On the sides of the hills in rear were numerous small springs of
excellent water, which were collected together and conveyed in
earthenware pipes to a large reservoir, placed by Mr. Brunton 70
feet above the highest house, which was itself about 60 feet above
the sea. From this reservoir the water was carried in iron pipes
down the centre of the long corridor, and at every ward (which was
placed at intervals at either side of the corridor) a leaden
service-pipe came off, and led an abundant and never-ceasing supply
into the ward cisterns, which supplied the baths, lavatories, and
closets. By this arrangement all necessity for pumping water was
avoided, and the sewers were able to be flushed very perfectly.
The lavatories and closets were placed at the ends of the wards
most remote from the corridor, and immediately outside them ran the
two main sewers, which at their sea terminations were carried some
distance into the Dardanelles.
The plan of the hospital may be at once understood by imagining a
covered way, open at the sides, and 22 feet wide, running nearly
east and west, and reaching for a length of more than a third of a
mile, on either side of which stood, at intervals of 27 feet on the
south side, and in most cases 94 feet on the north, the thirty-four
houses, each of which, as already said, was 100 feet long, 40 feet
wide, 12 feet high at the eaves, and 25 in the centre, and was
capable of containing fifty patients, with an allowance of nearly
1,300 cubic feet of air for each man. Some portion of this space
was occupied by the closets and some small rooms used as orderlies’
and bath-rooms. Thirty of these houses were used as wards; four
were used as dispensaries and purveyor’s stores. A drawing by Mr.
Brunton, showing the arrangements of one of the wards, is
attached.[189]
[Illustration: Fig. 22. RENKIOI HOSPITAL.
WARD BUILDING.
A. Corridor
B. Ward room
C. Orderlies’ bed-room
D. Bath-room
E. Medical officer
F. Lavatory, &c.
_g._ Ventilating fan
_h._ Ventilating air-trunk
_i._ Main drain
_j._ Tables in wards
_Transverse Section._
_Longitudinal Section._
_Ground plan._
_Scale of feet._]
To the south of each division of ten houses was placed an iron
kitchen, which afforded the necessary accommodation for preparing
500 diets.
At the inland extremity of the corridor were placed two iron
laundries, the water from which (some 4,000 gallons daily) was
passed into the sewers. Beyond the laundries were placed on either
side the wooden houses of the medical and other officers, who were
thus able to see down either side of this long line, and to
preserve to a certain extent surveillance over the patients.
The two smaller hospitals were constructed on a similar plan, each
range having, however, only one iron laundry inland, and one iron
kitchen in the centre of the range.
About half a mile from the hospital, close to the sea in the south
bay, three store-houses were erected, and a railway led from an
adjacent jetty or pier by the side of these store-houses to the
centre of the main hospital. Had the war continued, it would have
been carried to the north pier and bay, and would also have had a
branch running along the corridor of each hospital, so as to
deposit the sick at the very doors of the wards into which they
were to go.
Nothing could exceed the simplicity of the whole arrangement; it
was a repetition of similar parts throughout; and experience
enables me to say, that nothing could be better adapted for a
hospital than this system of isolated buildings, between every one
of which was a large body of moving air, rendering ventilation
easy, and communication of disease from ward to ward impossible.
The introduction of the covered way connecting the various houses
was a happy idea. In the summer this corridor was left quite open
at the sides, and formed a cool walk for the convalescents; while
in winter we boarded up its north side, so that in the coldest
blasts of the northern wind the men were protected, and were able
to leave their wards and to take exercise. I need only further
observe that, in order to secure perfect ventilation, not only were
openings left under the eaves and in the gables of the buildings
(which could be closed in cold weather), but air-shafts were placed
under the floors through which 1,000 cubic feet of air per minute
could be forced into the wards by fans placed in the corridor and
worked by hand [see fig. 22]. As the amount of wind at Renkioi was
always considerable, we never had occasion to use these machines;
but had the hospital been placed in a less airy situation, they
would have been of the greatest use.
For the construction of this hospital every necessary part was sent
out by Mr. Brunel. The houses were erected with great care by Mr.
Brunton, assisted by Mr. Eassie, jun., and by eighteen English
workmen (thirteen carpenters, one pipelayer, three plumbers, and
one smith) sent out for this purpose. On account of the size and
height of the houses (which were many times the size of the largest
Crimean huts), the framework was obliged to be put together very
carefully, and Mr. Brunton felt it necessary to employ none but
the English workmen on this duty; consequently the erection of the
houses took much longer time than we originally anticipated; but
during the winter we had reason to be satisfied that Mr. Brunton
had done wisely, for, in spite of the heavy winds we often had, no
finished house was ever damaged, except in one or two instances to
a very slight amount.
The erection of the houses was commenced on May 21, 1855. On July
12, I reported the hospital ready for 300 sick; on August 11, it
was ready for 500, and on December 4, for 1,000 sick. By January
1856, viz. seven months after its commencement, it was ready for
1,500 sick; and when the works were discontinued, at the end of
March 1856, we could, with a little pressure, have admitted 2,200
patients. In about three months more this immense establishment for
3,000 sick could have been finished and in full activity.
On the working of the system, Dr. Parkes says in his report:--
Although the hospital was ready for 300 patients on July 12, 1855,
we were not called on to receive sick till October 2. From that
time till February 11, eleven ships arrived from Balaclava and
Smyrna.... After February 11, 1856, we received no more sick. The
total number of military patients who were received from these
ships was 1,244, and, in addition, 87 soldiers were admitted,
either from the guard at Renkioi or Abydos, from transport ships
which touched at Renkioi, or from the English soldiers attached to
the Osmanli Horse stationed at the town of Dardanelles during the
summer and autumn.
The total number of admissions was 1,331--
Cured 961
Invalided 320
Deaths 50
Besides the military patients, we admitted 77 civilians.... The
total number of patients actually treated was 1,408, the largest
number at any one time 642....
The anticipations we had formed of the health of the spot and of
its adaptability for a hospital were quite confirmed by the
experience of more than a year. The winter was mild, and the
climate seemed especially adapted for pulmonary complaints, of
which we had a large number. The changes of temperature, it is
true, were very sudden and great; but as the men had warm wards,
these changes were not felt, and there were few days in which the
most delicate consumptive patient could not get out into the
sheltered corridor for a short time during the day. The
construction of the hospital was admirably adapted for men
recovering from illness. As all the wards were on the ground, as
soon as a man could crawl he could get into the air either in the
cool and sheltered corridor or in the spaces round the hospital.
* * * * *
In April and May 1856 the greater number of the patients had been
either discharged or invalided home, and ... the medical and
nursing staff was reduced more than one-half, and ... in the middle
of July the remaining staff was sent home.
All the stores which were likely to be used or to sell well in
England were sent home, and everything else was sold on the ground.
Major Chads, with twenty soldiers, and Mr. Brunton remained behind,
to superintend the sale of the buildings, which took place on
September 20.
CHAPTER XVI.
_MR. BRUNEL’S PROFESSIONAL OPINIONS AND PRACTICE._
SCHEME OF THE CHAPTER--MR. BRUNEL’S POSITION IN RELATION TO THE
COMPANIES OF WHICH HE WAS ENGINEER--LETTER ON THE DIRECTION OF
RAILWAY WORKS IN ITALY (MARCH 4, 1845)--LETTER ON THE POSITION OF
JOINT ENGINEER (OCTOBER 16, 1843)--LETTER ON THE POSITION OF
CONSULTING ENGINEER (DECEMBER 30, 1851)--LETTER ON THE POSITION OF
THE ENGINEER IN RELATION TO THE CONTRACTORS (MAY 26, 1854)--LETTERS
ON THE POSITION OF THE ENGINEER IN RELATION TO THE DIRECTORS (APRIL
15, 1850; DECEMBER 6, 1851; JANUARY 22, 1857)--MR. BRUNEL’S
ASSISTANTS--LETTERS ON INTERFERENCE OF DIRECTORS WITH THE ASSISTANT
ENGINEERS (JANUARY 19, 1842; JANUARY 28, 1842; JANUARY 12,
1851)--MR. BRUNEL’S PUPILS--HIS RELATIONS WITH OTHER
ENGINEERS--INVENTORS--LETTER IN REPLY TO AN INVENTOR (SEPTEMBER 17,
1847)--MR. BRUNEL’S VIEWS AS TO STATE INTERFERENCE--LETTER ON THE
ROYAL COMMISSION ON THE APPLICATION OF IRON TO RAILWAY STRUCTURES
(MARCH 13, 1848)--LETTER ON A PROPOSAL TO OBTAIN THE RECOGNITION IN
ENGLAND OF DECORATIONS CONFERRED AT THE PARIS EXHIBITION OF 1855
(FEBRUARY 9, 1856)--MR. BRUNEL’S OPINION ON THE PATENT
LAWS--MEMORANDUM FOR EVIDENCE BEFORE THE SELECT COMMITTEE OF THE
HOUSE OF LORDS ON THE PATENT LAWS, 1851--EXTRACT FROM OBSERVATIONS
ON THE PATENT LAWS, MADE BY MR. BRUNEL AT A MEETING OF THE SOCIETY
OF ARTS (MARCH 26, 1856).
It is proposed in the earlier part of this chapter to describe,
principally by extracts from Mr. Brunel’s correspondence, the position
occupied by him in regard to the Companies which he served, and to the
various classes of persons with whom he acted in the discharge of his
duties as engineer to those Companies. These selections are followed by
extracts relating to questions of general professional interest.
* * * * *
The first point to be considered is, his relations with the Companies
which employed him as their engineer, and with the Directors who formed
the governing body.
Mr. Brunel conceived that he was, by virtue of his appointment as
engineer, the sole and confidential adviser of the Company in all
matters relating to the construction and mechanical working of the
undertaking. He did not permit any one to be associated with him in the
supreme control over those matters which were in his department; and the
moment he thought that confidence was no longer placed in him, he was
prepared at every sacrifice to resign his office. But, as long as he was
supported by the Directors, he thoroughly identified himself with their
cause, and he never allowed considerations of health or convenience or
pecuniary advantage to interfere with the performance of any service
which he could render them. The fearless independence of his position,
combined with his absolute devotion to the interests of his employers,
was no doubt the secret of the immense influence he acquired, and of the
affectionate esteem with which he was regarded by those whom he served.
_On the Direction of Railway Works._
March 4, 1845.
I have well considered the communication which you did me the
honour of making on the part of the Government of His Majesty the
King of Sardinia with reference to my undertaking the direction of
the works of the proposed railway from Genoa to Alessandria, about
to be executed by the Government itself....
In the first place I assume that if the direction of the works be
confided to me as the engineer, the same degree of confidence will
be placed in me, and the same authority will result from that
confidence, as would be the case in England--that is to say, I
should be the confidential adviser of the Government in all
engineering questions connected with this railway, my
communications would in all matters be made direct with the
Government, and as long as I continued to be responsible for the
direction of the works no other engineer would be consulted or
allowed to interfere. Of course I claim no right to direct anything
but that which has the sanction of the Government; but I should
claim to be their sole adviser on all engineering points (connected
with the construction of the railway), and to possess their entire
confidence; and also that, if any portion of that full confidence
were at any time withdrawn, the fact should be immediately
communicated to me; when, after making every possible arrangement
to prevent inconvenience to the Government, I might withdraw from
the direction of the work. This is the position which an engineer
of any standing occupies in this country, whether acting for the
Government or for individuals; and I believe it to be as fully
essential for the success of the proposed undertaking, and as
necessary for the interests of His Majesty’s Government as for my
satisfaction, that I should be placed in a similar position.
The circumstance of my being a foreigner, of my being rarely
present to meet objections, if any are raised, of the unavoidable
frequency of real as well as apparent failures in works of such
variety and so numerous as those which occur on this line, of the
difficulties which always attend the introduction of novelties and
everything connected with a railway, the rapid mode of its
construction, the necessity which experience has proved of
frequently adopting apparently hasty and hazardous methods to
prevent the evil consequences of protracted delays,--all this will
be novelty with you as it was a few years ago in England, all these
circumstances combine to render it peculiarly essential to the
satisfactory progress of the undertaking that it should be well
known to all parties that full and entire confidence is placed in
me by the Government.
It will of course also be necessary that all parties acting under
me in the direction of the works should feel that their appointment
or dismissal depends entirely upon me.
In return for the confidence thus placed in me and the authority
given to me, I should of course know no interest but that of the
Government. If the Government is willing to appoint me engineer
according to this definition of my position, I shall feel pride in
the appointment, and I shall devote my best energies to the
accomplishment of one of the finest and most interesting works of
the day....
_On the Position of Joint Engineer._
October 16, 1843.
The contents of your letter of yesterday take me quite by surprise;
the expression you use of joint-engineership implies a view of our
relative position diametrically opposed to the views which I have
plainly and unequivocally expressed to you and to the Directors
when such a thing as joint-engineership was proposed to and
rejected by me....
You wind up your letter by saying ‘we have accepted the duty of
joint-engineers,’ &c., and you add a postscript requesting me to
lay your letter before the Directors: this I should have been
obliged to do without any such request. I never accepted the duty
of joint-engineer; I have always refused to do so. I thought I had
made this very clear both to you and the Directors on several
occasions; indeed I often feared that I expressed myself too
strongly instead of leaving it capable of misapprehension....
_On the Position of Consulting Engineer._
December 30, 1851.
I shall be happy to act in any capacity (subject to the exception I
will further explain) which can be useful to your Company; ... but
the exception I have to make is one which perhaps resolves itself
merely into a question of _name_. The term ‘Consulting Engineer’ is
a very vague one, and in practice has been too much used to mean a
man who for a consideration sells his name, but nothing more. Now I
never connect myself with an engineering work except as the
Directing Engineer, who, under the Directors, has the sole
responsibility and control of the engineering, and is therefore
‘The Engineer;’ and I have always objected to the term ‘Consulting
Engineer.’ ...
In a railway the only works to be constructed are engineering
works, and there can really be only one engineer; and in your case
especially, where, as I apprehend, the contractor is part of the
company, and has to be treated with consideration, and perhaps less
vigorously, at all events differently from an ordinary contractor,
considerable management and discretion will be required of your
engineer, and a degree of responsibility which I would only
undertake if sole engineer. Possibly this is what you meant, and
that I alone see the distinction, but it is an important one with
which you may not be so familiar as I am.
_On the Position of the Engineer in Relation to the Contractors._
May 26, 1854.
I have in due course taken steps to prepare a report for the
Directors on the state of the work, but you must not apply to the
contractors for such reports. In the first place, it would lead to
ridiculous contradictions, inasmuch as most likely my reports
would differ materially from theirs; and also it would reverse the
whole order of things. I must alone, so long at least as I am the
professional adviser of the Company, be the medium of communication
with contractors in all matters which the terms of the contract
refer to me. I am very particular about the regularity of all these
forms, because, although, while all goes smooth, they are of no
consequence, yet if, unfortunately, any little difficulties arise,
then it is unpleasant and difficult to alter a previous course.
I would ask, then, that all official communications with the
contractors should be made through me, and that, even as regards
these, we should confer together before any formal resolution
should at any time be passed, so as to be sure that it is properly
worded, and that no awkward precedent is established.
You may have seen that a great appeal case before the Lords,
affecting claims of some hundreds of thousands, has just been
finally decided in favour of the Great Western Railway Company
after fourteen years of litigation;[190] and this favourable
decision was entirely obtained by carefully prepared
specifications, and by my not having departed in any single case,
in years of correspondence, from the letter and spirit of the
contract, and particularly from the fact--strongly commented upon
by Lords Cranworth and Brougham--that I had maintained my position
of umpire between the Company and contractor. It is, then, as
essential to the Company as to the contractor and to me that I
should maintain that position.
_On the Relations between the Engineer and the Directors._
I.
April 15, 1850.
You will remember that on the 2nd of November last I addressed you
a letter on the subject of my acting as umpire in several cases of
reference between the Company and contractors, who were raising
heavy claims against the Company, in which I expressed my readiness
to act in a very responsible, laborious, and thankless position....
I am also still acting, so far as my services can be useful, as
your engineer; and in arranging with contractors, &c., there is
even now much remaining to be done. As long as I enjoy your full
confidence, it would be a great pleasure to me, although the
profit might for the present be small, to continue your engineer,
looking forward, as I do, at no distant period to the completion of
the works; but the changes that have lately taken place in the
Board, and the excitement which has been displayed by some of your
proprietors in effecting those changes--such excitement as is too
apt frequently to lead men to form most unjust and erroneous
opinions of the trustworthiness of those who have been long engaged
in their service--very naturally causes anxiety. I, and you who
have been acting with me for so long, know that I have always
advised you honestly, and I hope generally wisely, on such matters
as I have been consulted upon, notwithstanding my known connection
with other and sometimes conflicting interests. But new men may not
have the same confidence in me, and I cannot afford to run the risk
of any doubts being entertained upon the subject.
I must therefore beg of you to bring the matter before the Board
formally, and if it is desired that I should continue to act as
your engineer, that I may have it clearly understood that I do so
with the full concurrence of the Board as now constituted, and
particularly of the new Directors; and that to render the
expression of their confidence clear, I wish them to understand
that I am quite ready to tender them my resignation if they do not
feel that confidence, and that such resignation cannot prejudice
any of the cases under arbitration before me, as I undertook them
upon the express understanding that it was as agreed umpire, and
not as engineer to the Company.
I shall only add that by being engineer to a Company, I mean acting
in perfect confidence with the Directors on matters generally, as I
have been in the habit of doing.
II.
December 6, 1851.
I really cannot consent to forego in this case the rule I lay down
for myself in my professional business, which is to yield as far as
I comfortably can to the mere wishes of Directors in the mode in
which I direct the works they may order, but not beyond this
point--and if the Directors of any body claim the right to control
the staff which I think necessary to carry on my work, I concede
the right at once, and resign the direction of that staff. The
staff for constructing engineering works is not a permanent
establishment, which can be extended or restricted just as a Board
of Directors may determine; it is much more of the character of a
personal staff attached to the engineer-in-chief, and by means of
which he is enabled to take great responsibility upon himself,
both in respect of the works which he executes, and the settlement
of large amounts of payments, in which settlement both the company
and the contractors are very much at his mercy. It is the duty of
an engineer of course to study economy as well as efficiency in his
staff, and to pay attention to the wishes of the Directors so far
as he can; but he must be the ultimate judge of the number and the
persons of that staff. At least, that is my rule, and I cannot
depart from it in this case. I should wish to state this as
respectfully as possible to the Board, but at the same time to
state it clearly.
III.
January 22, 1857.
...I have replied very fully to the observations of the Directors,
but having done so I must again place my resignation in the hands
of the Directors. A Board of Directors has a perfect right to
dispense with the services of an engineer, or to lay down any rules
of conduct they may think fit, and to engineer the works
themselves, either as a body or by appointing one of their members,
if they think fit; but if they desire to have the advice and
responsibility of any respectable engineer--at all events, if they
wish to have mine--they must place the usual amount of confidence
in me; and as long as I am engineer they must leave me to conduct
the engineering, and must act as if they assumed that I was more
able to advise the Board upon all the usual practical questions of
engineering than any one of the Directors. Admitting as I do the
full right of a Board of Directors to determine whether they will
have an engineer or not, if they have one they must trust him to do
his own work.
As a mere question of time it would be impossible that I could be
constantly entering into long explanations of the most trifling
character upon points on which I must be by far the most competent
judge--and in fact the competent and responsible judge, expressly
employed, and paid professionally because I am so. If individual
Directors are more competent than their engineer, let them assume
the office and the responsibility; but do not have a divided
responsibility. I am most happy at all times to receive any hints
or suggestions from any body whether Directors or not, but I cannot
undertake the labour of replying to them all, neither can I act as
engineer to a Board of Directors who, either as a body or by one or
two of their members, make a practice of taking upon themselves to
judge of those details of which I must be assumed to be the
competent judge, and thereby interfering with my proper duties. If
the engineer is not assumed to be worthy of trust both in respect
of zeal in the interests of the Company, and very superior to any
one of the Directors as regards experience, and ability to carry
out what the Directors may determine upon, he is not fit to be the
engineer; but if he is so, he must be left to carry out those
details of his department of the business. These are the general
principles upon which alone I can act.
It is, from the nature of the case, impossible by any extracts from Mr.
Brunel’s correspondence to give an adequate idea of the position which
he occupied in relation to his assistants. There was so much personal
intercourse between them that letter writing was but little resorted to.
His relations with them were of the most affectionate and intimate kind,
and were maintained without any ostentation or outward show. He was in
the habit of placing entire confidence in his subordinates as long as he
considered that they deserved it; and, while he preserved his own proper
position, he was always ready to shield them from the interference of
others. The letters which are printed below are evidence of this. When,
on the other hand, anything occurred to displease him in the conduct of
his assistants, he was eager to give the offender a chance of retrieving
his position; and he was always ready to help them in any difficulties.
_On Interference of Directors with the Assistant Engineers._
I.
January 19, 1842.
While I am upon the subject, and as I have referred to the impolicy
of Directors taking notice of little things, and as I speak freely
to you, I will mention that I have observed with pain on some
occasions this tendency; and I will give one instance of what I
must call most unwise interference. It was lately, and
unfortunately at the same moment as this complaint, intimated that
a pair of boxing gloves had been seen in one of the Company’s
offices, and that _the Directors had observed it_. Now I really do
not know why a gentlemanly and industrious young man like ----
should be subject to have his trifling actions remarked upon more
than I myself, unless the observer gave him credit for a much more
gentle temper than I possess; because I confess, if any man had
taken upon himself to remark upon my having gone to the pantomime,
which I always do at Christmas, no respect for Directors or any
other officer would have restrained me. I will do my best to keep
my team in order; but I cannot do it if my master sits by me, and
amuses himself by touching them up with the whip.
II.
January 28, 1842.
I am much obliged to you for your letter. I am sorry to find,
however, that the impression, a very erroneous one as I believe,
remains upon your mind that the assistant engineers are predisposed
to encourage, or at all events allow, improper conduct on the part
either of contractors or the inferior agents of the Company....
From some experience in these matters it is that I have come to the
conclusion that it is wise (however strange you may think the
doctrine to be) to shut one’s ears and eyes really and truly to
everything which does not come forward in such a shape as to demand
and admit of an enquiry; and it is for this reason also that I do
entertain the opinion very strongly (in which you appear to differ
from me), that it is not the interest, it is not wise, and
therefore only it is not the duty of Directors to look after, or to
see into, the smaller details of the conduct of an establishment
which, being of a very temporary, changing, and uncertain
character, cannot at the best be conducted with the discipline and
regularity of a permanent establishment, in which the parties have
their clearly defined and unchanging duties, and look forward to
the permanent occupation of their places as their means of support.
At all events, when the Directors see anything they think desirable
to correct or to modify, they can fully communicate it to me
without the possibility of giving to me any soreness of feeling,
which it is always desirable not to excite, even in the case of the
lowest menial whose best services one wishes to have and use.
III.
December 12, 1851.
With reference to your letter of December 11, stating that the
Directors ‘are satisfied that great irregularities have existed,
and that they feel it to be their duty, and will not hesitate on
any occasion, to represent to me any irregularity on the part of my
staff that may come to their knowledge,’ I am almost afraid, unless
in a short note you may have failed to convey to me the meaning of
the Directors, that they greatly misunderstand my feelings on the
subject; my great desire, as great as, possibly greater than even
that of the Directors, who cannot feel so personally responsible as
I do for the efficiency of my staff--my great desire I say is to
hear immediately from anybody, and particularly of course from a
Director, of any supposed irregularity; and I should feel that I
had ground of complaint even if any such report or any suspicion of
any irregularity were not immediately communicated to me. The
moment that the Directors could doubt my being as anxious as they
can be to know and to remedy any irregularity, or that they should
look upon me in such matters otherwise than as one of themselves, I
should feel that I had lost their confidence, and could no longer
carry on satisfactorily to myself my duties, and should therefore
resign them. Such must, I beg, be our relative position as regards
the future; and carrying out this principle as regards the past, I
must beg of them to tell me explicitly what are the irregularities
to which they refer as having been committed. I ought to be fully
informed of such things--indeed, nothing ought to be suspected even
without my knowing; for if _I_ ought not to know, who ought?
As a matter of form, and to be strictly correct, I must guard
myself against being supposed to mean that I could desire or
approve of what the Directors I am sure would also disapprove
of--namely, a system of fault-seeking--because in a very numerous
staff or body of men, particularly where they have not the benefit
of permanent situations, the perfection of regularity cannot be
hoped for; what I principally seek and require of my assistants is
an honest discharge of their duties, and any departure from this it
is well known amongst them I never overlook. Have the goodness,
therefore, to ascertain for me, and to let me know immediately,
what these irregularities have been.
A few words may here be added on Mr. Brunel’s practice in reference to
taking pupils.
Although many of his assistants had been his pupils, he did not
encourage young men to come to him with the object of learning their
profession in his office. He never absolutely declined to take pupils;
but he endeavoured, by fixing a high premium, to reduce the number of
applicants.
He did not profess to do more for his pupils than to give them the
opportunities of seeing work, afforded by his office, and the chance of
being afterwards employed as his assistants. He attached much importance
to private study of mathematics and other branches of science.
* * * * *
Passing on to the position assumed by Mr. Brunel in his relations to the
profession at large;--it may be stated in a few words, that he was
desirous on all occasions of promoting its welfare by encouraging
friendly intercourse among its members, by healing strife, by
suppressing as far as he could all cant or pretension, and by setting
his face steadfastly against all attempts to fetter the freedom of
invention or to lessen the independence of engineers by State patronage
or control.
It may appear strange to affirm of one who was foremost in almost all
the professional contests of his time, that he was zealous in healing
strife; but it is nevertheless true that Mr. Brunel, while he was a bold
and uncompromising advocate of his own schemes, was at the same time
untiring in his exertions to limit the area of controversy, to confine
it strictly within its proper bounds, and to divest it of all
personality or of anything which could lead to unpleasant feeling or
annoyance.
His endeavours to this end were greatly helped by the friendly relations
which he maintained at all times with his professional brethren. He
never allowed any divergence of opinion to interfere with private
friendship; and, even in the height of controversy, he was glad to give,
and ready to ask for, advice on matters connected with the scientific
departments of civil engineering.
It is but seldom that extracts have been made from Mr. Brunel’s private
journals; but it may be permitted, in illustration of what has been said
on this point, to give the following passage, written during the great
contests of the year 1846.
May 5, 1846.
I am just returned from spending an evening with R. Stephenson. It
is very delightful, in the midst of our incessant personal
professional contests, carried to the extreme limit of fair
opposition, to meet him on a perfectly friendly footing, and
discuss engineering points.... Again I cannot help recording the
great pleasure I derive from these occasional though rare meetings.
Mr. Brunel’s opinions on the working of the patent laws will be given
below, as following more fitly after extracts from his correspondence
relating to the position of his profession in regard to the Government;
but, before entering upon that subject, a few words may be said in
reference to a class of persons who formed a very large proportion of
his correspondents--the class of ‘Inventors.’
He used to receive numerous applications from persons who had invented,
or who thought they had invented, some useful contrivance, from a
locomotive which would save fifty per cent. in fuel over those then in
use, to a machine which, as Mr. Brunel assured its inventor, ‘would not
even have a tendency to move.’ He was always ready to encourage
inventions which seemed likely to produce good results, and to enquire
into their merits, if they were patented; but not otherwise, lest it
should be said that confidence had been placed in him.
The following is one of the many letters he had to write in answer to
requests of this nature.
September 17, 1847.
I could not have complied with your request of giving any opinion
upon the merits of the invention. Simple as such an act may be, it
too frequently involves one in controversy; and I never found,
before I made the rule not to give opinions, that my advice was
ever followed, if it was to discourage the inventor from further
expense and trouble.
I should tell you in this case that the idea of dovetailing, which
in your first letter I find was the principle of the invention, had
long before been worked out in every shape and form that ingenuity
or blundering could possibly give it.
Upon the important question how far, if at all, the practice of civil
engineers should be subject to State control, Mr. Brunel held very
decided views. He was strongly opposed both to any interference on the
part of the State with the freedom of civil engineers in the conduct of
their professional work, and to the recognition of merit by the bestowal
of honours or rewards.
_On the Royal Commission on the Application of Iron to Railway
Structures._[191]
March 13, 1848.
I regret that the Commissioners should have done me the honour of
requesting ‘my opinion upon the enquiry referred to them;’ because,
as it is known to one or more of these Commissioners that I have
expressed very strongly, both publicly and privately, my doubts of
the advantage of such an enquiry, and my fears of its being, on the
contrary, productive of much mischief, both to science and to the
profession, it would expose me to a charge of weakness and of
inconsistency if I were now to refrain from expressing those
opinions, which otherwise I had no idea of intruding upon the
Commissioners; and, indeed, I had hoped that, by making those
opinions known to some of the members, I might have been passed
over, and not invited to assist in the proceedings.
I shall be most happy to communicate, as I am at all times most
anxious to do, any knowledge which I may obtain in the course of my
practice, and such intercommunication of ideas and of experience
amongst engineers I believe to be most useful; but the attempt to
collect and re-issue as facts, with the stamp of authority, all
that may be offered gratuitously to a Commission in the shape of
evidence or opinions, to stamp with the same mark of value
statements and facts, hasty opinions and well-considered and
matured convictions, the good and the bad, the metal and the dross
(and simple courtesy to the donors must prevent the Commissioners
from attempting to draw distinctions which might appear
invidious)--this, I believe, always has rendered, and always will
render, such collections of miscalled evidence injurious instead of
advantageous to science; and the facts or statements and opinions
so collected will form generally, I believe, a lower average of
information than that which is already in the possession, or at
least within the reach, of those who have occasion to study the
subject: for it is remarkable that in this particular enquiry the
Commissioners can have no peculiar means of obtaining, and, as I
believe, cannot hope to get better or more extended information
than that possessed by any one of the principal engineers of the
day; while they will be compelled to receive and to publish much
that a prudent man, acting on his own responsibility, would either
not have attended to, or would silently have rejected. This,
however, is perhaps a negative evil, or, at most, one which cannot
much affect the proceedings of the well-informed in our profession;
but the mischief which I anticipate is much more dangerous to the
progress of science.
If the Commission is to enquire into the conditions ‘_to be
observed_,’ it is to be presumed that they will give the result of
their enquiries; or, in other words, that they will lay down, or at
least suggest, ‘rules’ and ‘conditions to be (hereafter) observed’
in the construction of bridges, or, in other words, embarrass and
shackle the progress of improvement to-morrow by recording and
registering as law the prejudices or errors of to-day.
Nothing, I believe, has tended more to distinguish advantageously
the profession of engineering in England and in America, nothing
has conduced more to the great advance made in our profession and
to our pre-eminence in the real practical application of the
science, than the absence of all _règles de l’art_--a term which I
fear is now going to be translated into English by the words
‘conditions to be observed.’ No man, however bold or however high
he may stand in his profession, can resist the benumbing effect of
rules laid down by authority. Occupied as leading men are, they
could not afford the time, or trouble, or responsibility of
constantly fighting against them--they would be compelled to
abandon all idea of improving upon them; while incompetent men
might commit the grossest blunder provided they followed the rules.
For, in the simplest branch of construction, rules may be followed
literally without any security as to the result. There is hardly a
branch of engineering that could have been selected which in its
present state is less capable of being made the subject of fixed
laws or instructions than the application of iron to railway
structures, and certainly there is no branch in which there is more
room for improvement, or which offers so many different channels or
directions for that improvement.
In the quality of the material, the workmanship, or the mode of
manufacture, and in the application of it, there is every
imaginable variety, there is room for almost any imaginable degree
or nature of improvement; and unless the Commissioners are endowed
with prophetic powers, it is impossible that they can now foresee
what may be the result of changes in any one of these
conditions.[192] ...
What rules or ‘conditions to be observed’ could be drawn up now
that would not become, not merely worthless, but totally erroneous
and misleading, under such improved circumstances? But above all, I
fear--nay, I feel convinced--that any attempt to establish any
rules, any publication of opinions which may create or guide public
prejudice, any suggestions coming from authority, must close the
door to improvement in any direction but that pointed out by the
Commissioners, and must tend to lead and direct, and therefore to
control and to limit, the number of the roads now open for advance.
I believe that nothing could tend more to arrest improvement than
such assistance, and that any attempt to fix now, or at any given
period, the conditions to be thereafter observed in the mode of
construction of any specific work of art, and thus to dictate for
the present and for the future the theory which is to be adopted as
the correct one in any branch of engineering, is contrary to all
sound philosophy, and will be productive of great mischief, in
tending to check and to control the extent and direction of all
improvements, and preventing that rapid advance in the useful
application of science to mechanics which has resulted from the
free exercise of engineering skill in this country, subjected as it
ever is, under the present system, to the severe and unerring
control and test of competing skill and of public opinion. Devoted
as I am to my profession, I see with fear and regret that this
tendency to legislate and to rule, which is the fashion of the day,
is flowing in our direction.
I must repeat my regret that circumstances should have forced me to
intrude these my opinions upon the Commissioners; but, for the
reasons I have before given, the application to me, after the part
I have taken, left me no alternative; but having expressed my
opinions, and respectfully protested against the objects and
proceedings of the Commissioners, I shall feel it my duty to attend
to their summons, and afford any information in my power.
_On a Proposal to obtain the Recognition in England of Decorations
conferred at the Paris Exhibition of 1855._
February 9, 1856.
I regretted to be under the necessity of declining to sign the
memorial that was brought to me by a gentleman introducing himself
with your card, without an opportunity of explaining to you my
reasons; and it would be difficult to do so satisfactorily without
an opportunity of personal explanation. In a few words, however, I
will state that I disapprove strongly, and after full
consideration, of any introduction into England of the system of
distinctions conferred by Government upon individuals, whether
engaged in professions, arts, or manufactures, whose merits can be
so much better and more surely marked by public opinion. In
countries where public opinion is not so searching and so powerful
as in England, the evils of favouritism may be out-balanced by the
advantages of some means of distinguishing men. I admit the
possibility, though I doubt the fact; but I feel sure that the
evils would be far greater than the advantages in England. The few
cases of knighthood conferred in England generally follow public
opinion, though I should not wish to see this system carried
further. Such being my opinion, I could not consistently ask for my
own letter of Chevalier de la Légion d’Honneur being recognised
here.
On the question of the patent laws, Mr. Brunel held the opinion that the
system of protecting inventions by means of letters patent was
productive of immense evil. The prominent part which he took in all
discussions upon this subject exposed him to much adverse criticism,
which was perhaps the more freely bestowed, because it was felt that he
was a very formidable opponent, not only from the force of his
arguments, but also from the authority with which he spoke.
He was, from the necessity of his position as a civil engineer, himself
an inventor; he had in his staff and among those with whom he acted many
inventors; he did not, therefore, underrate the benefits conferred on
science by those who, by inventing, add to its resources. He was
continually being trammelled and thwarted in his various undertakings by
patents, and he therefore could judge of their evil effects upon the
progress of practical engineering; and, lastly, he had the best possible
means of judging of their effects upon the inventors themselves, both
from his opportunities of becoming acquainted with the fate of others,
and from his own experience. His father, Sir Isambard Brunel, had taken
out patents for most of his inventions, and, as Mr. Brunel stated before
the House of Lords Committee of 1851, with very unfortunate results,
especially in the case of the carbonic-gas engine (see Note B to Chapter
I); where, if they had not been obliged to work secretly, in order to
conceal the process before the patent was granted, they could have
obtained valuable advice, which might either have led to an earlier
abandonment of the project, or to its improvement in those points in
which it failed.
Mr. Brunel drew up the following statement when asked to give evidence
before the Select Committee of the House of Lords in 1851. His evidence
will be found at p. 246 of the Minutes of Evidence (ordered to be
printed July 1, 1851).
_Memorandum for Evidence before the Select Committee of the House
of Lords on the Patent Laws, 1851._
I have for many years had considerable experience of the operation
of patents.
I have been engaged under my father in the working out of numerous
inventions of his, and the taking out of patents on his account,
also in advising others professionally with him, and by myself, and
have been engaged in numerous questions of disputes resulting from
patents; and I have had frequent occasion to use the patents and
inventions of others. I have also had to introduce improvements of
my own without patents, and to defend my use of them against
patents.
I have thus for the last twenty-eight years been in the midst of
everything connected with inventions, and in constant contact with
the operation of the patent laws.
I have been behind the scenes the whole time.
The result has been that I have never taken out a patent myself, or
ever thought of doing so; and I have gradually become convinced
that the whole system of patents is, in the present advanced state
of arts and science and manufactures, productive of immense evil.
I think that it does nothing of what it professes to do, and which
I believe to be impracticable in the present state of things, but
that, on the contrary, it impedes everything it means to encourage,
and ruins the class it professes to protect, and that it is
productive of immense mischief to the public.
I should wish to observe that my opinions are not formed from any
theory, or from any consideration of what are or ought to be the
laws of patents, or whether the details of such laws are capable of
improvement or otherwise; but they are simply the result of a very
long and tolerably intimate knowledge of the operation of the hope
of protection held out, and the operation of that protection such
as it can be when obtained; and these results do not, in my
opinion, depend at all upon any question of whether patents are
cheap or dear, whether they are granted sparingly or profusely, by
a simple or by complicated machinery; it is the ruinous effects
upon the class of inventors, of the false dreams and hopes excited
by the system, and the injurious effect upon improvements of the
greater or less degree of exclusive privilege which is attained,
which I have had constantly before my eyes for so many years, and
which must be increased by any real improvement of the patent laws.
I should, therefore, be an advocate for very cheap patents granted
with great facility, to the poor illiterate workman, as well as to
the rich manufacturer with his counsel and agents, and as well
protected as legal ingenuity can devise.
If the system is good in principle it must bear extension, but I
believe it could not stand a twelvemonth under such a test--every
evil now inherent in the system would be greatly increased in
quantity, and the absurdities which are now ascribed to errors of
detail would all become so evident that the system would be
abandoned by universal consent.
I believe, paradoxical as it may seem, that the privileges thus
promised and granted to inventors are most injurious to them. To
understand this, it must be known and borne in mind that useful
inventions or improvements in the present day, certainly in nine
hundred and ninety-nine cases out of a thousand, are not new
discoveries, but generally slight modifications of what is already
in use; judicious applications of known principles and of
well-known and common parts of machinery, or of common substances,
very often mere revivals or re-inventions of something which had
many times previously been thought of, and perhaps tried, and
failed from the want only of some substance or of some tool which
has since been introduced.
I believe that the most useful and novel inventions and
improvements of the present day are mere progressive steps in a
highly wrought and highly advanced system, suggested by, and
dependent on, other previous steps, their whole value and the means
of their application probably dependent on the success of some or
many other inventions, some old, some new. I think also that really
good improvements are not the result of inspiration; they are not,
strictly speaking, inventions, but more or less the results of an
observing mind, brought to bear upon circumstances as they arise,
with an intimate knowledge of what has already been done, or what
might now be done, by means of the present improved state of
things, and that in most cases they result from a demand which
circumstances happen to create. The consequence is that most good
things are being thought of by many persons at the same time; and
if there were publicity and freedom of communication, instead of
concealment and mystery, ten times or a hundred times the number of
useful ideas would be generated by each man, and with less mental
effort and far less expenditure of time and money.
In the present state of things, if a man thinks he has invented
something, he immediately dreams of a patent, and of a fortune to
be made by it. If he is a rich man he loses his money, and no great
harm is done; but if he is a workman, and a poor man, his thoughts
are divided between scheming at his machine in secret, and scheming
at the mode of raising money to carry it out. He does not consult
his fellow-workmen, or men engaged in the same pursuits, as to
whether the same thing had ever been tried, why it had failed,
what are the difficulties, or (what is most probable) whether
something better is not already known, and waiting only the demand.
In nine cases out of ten he devotes his time and money to the idea,
instead of pursuing his legitimate and natural pursuits. In
elaborating this idea his whole thoughts are turned to the means of
making it different from what he may happen to know of similar
ideas, so that he may secure a patent, rather than to an honest
endeavour to obtain the most useful result. He does not make use of
other good ideas which may be already patented or in use, even if
he knows of them, because his sole object thenceforth is not
improvement, but ‘exclusive right.’ After much time and money spent
in experiments, he takes out a patent. I will assume that the mere
patent costs him nothing, but the waste of time and money in
elaborating his idea is generally considerable, and far more
serious in its effects upon the man than the payment of the fees
now demanded for a patent. When his patent is complete, and his
invention published, the chances are, and ever will be, one hundred
or one thousand to one that it is not worth a sixpence as an
exclusive right which others will buy of him: every chance is
against him.
_In the first place_ it must be a good thing, it must be an
improvement upon the very ‘best thing’ of the same sort: the
chances are of course great against this.
_Secondly._--It must be new, nothing of the sort must have been in
use before--how very few things can be devised which will bear this
test. I do not know of half-a-dozen clear cases of distinctly new
inventions since I have been acquainted with machinery and science;
and, judging from analogy, I cannot bring my mind to believe that
these would bear the test of a strict and searching enquiry by
interested parties. The chances are then immensely against his
invention, if good enough to be disputed, proving to be new enough
to stand as giving a claim to exclusiveness.
_Thirdly._--It must not depend for its success upon the use of some
other exclusive and privileged invention, or else of course it is
of little saleable value, even if not an infringement upon the
previous patent.
_Fourthly._--There must be a demand existing or creatable for the
article produced; or, like many other good things, it will be out
of time, and drop accordingly.
_Fifthly._--He must find some parties whose interest it is to
encourage the introduction of the change, and who have the means of
combating those interests which are embarked in previous
monopolies.
Since all these conditions are necessary for success, it is not
surprising that the result should be, as I am positive that it is
in practice, that the aggregate of individual benefit derived by
the exclusive privileges granted, is greatly below the aggregate
expenditure of time and money involved in the production of the
whole, taking the good and bad; but the proportion of the aggregate
benefits as compared with the cost to the real inventor is still
less.
It is known to all persons acquainted with the subject that, in
nine cases out of ten of successful inventions, the patents are not
beneficially enjoyed by the original inventor. And it always must
be so. The mere original invention forms generally but a small part
of the whole business or merit of bringing into useful operation
any new thing. Judgment, a knowledge of the world, and of business
and other qualities not particularly belonging to inventors, are
just as requisite as mere ingenuity, although they are not the
subject of protection. Capital and connection are also generally
required. All these command, as they ought to do, a large share in
the ultimate profits, but it is rare that an inventor at once finds
such a partner. The invention generally changes hands once or
twice, or oftener, till some chance brings it into operation; and
ultimately it is (as must be admitted by all who know anything
about these matters) very rarely, even in the case of good things,
that the party who originated the subject of the patent has
ultimately any large beneficial interest in it; and certainly, from
these and all the other causes mentioned, it is an undoubted fact
that inventors, on the whole, make a heavy annual loss, quite
irrespective of mere patent fees, by inventions and patents, and
that patents are not therefore a benefit to the present class of
inventors, and particularly not to the poorer members of the class.
Without the hopes of any exclusive privileges, I believe that a
clever man would produce many more good ideas, and derive much more
easily some benefit from them. It is true that he will aim only at
earning a few pounds instead of dreaming of thousands; but he will
earn these few pounds frequently, and without interfering with his
daily pursuits; on the contrary, he will make himself more useful.
An observing man sees what he thinks to be a mode of increasing the
production of a certain machine or manufacturing operation in which
he is engaged, or a better mode than that which he is acquainted
with of producing some article. In all probability the same
circumstances which led him to make the observation have attracted
the attention of others before him; perhaps, at the same time, a
little free communication with his fellow-work men or with other
manufacturers or men of science would show him that there were
insuperable difficulties, and he would turn his attention at once
to other things, or that there were better ways of doing the same
thing, or, by pointing out difficulties, enable him to avoid
useless investigations, or to make a change that would vastly
improve his scheme; or he would communicate his ideas, instead of
wasting his time in elaborating them, which very possibly others
more acquainted with the particular branch would do much better
than he; if he is a workman, his master would give him something
for the idea, or if not, his value as a workman would soon become
known. It is a great error to suppose that stupid men can live upon
the clever man’s brains if they are all left free scope in the use
of their intellect; but if by artificial means an exclusive right
or property in an idea can be secured, then of course the thief may
steal the idea, and having registered his property in it, his
inferiority of intellect is more than counterbalanced. Intelligent
men who would always be suggesting improvements in a manufactory
would soon become necessary, and would be valued accordingly. A
manufacturer who was not surrounded by such assistants would stand
no chance in the general competition, and what is necessary and
valuable will in England fetch its price; and thus clever workmen
will get well paid, and earn much more, and that more healthily,
than the whole body of schemers now do.
The impediments thrown in the way of improvements by the existence
of patents will hardly be credited by those who are not familiar
with the operation of them. In the present state of things they
create such barriers that it is almost wonderful that any
improvements can be effected.
It will not be difficult to understand that, from the infinite
number of patents that are now taken out, it is hardly possible to
devise a mechanism or a chemical combination that does not, in some
shape or other, form part of some previous invention or process.
This would be the case even if patents were only taken out to
secure real, or what are believed to be real, inventions. But the
shoals of patents have brought into existence animals to feed upon
them. There is a trade which nothing can destroy as long as patents
last, and which must increase with the increase of patent, whatever
may be the mode of granting them. Patents are taken out even in
very general terms, so as to embrace everything that can resemble
some probable or imaginary improvement, and then, like a spider in
his web, the patentee watches for his victims. Besides this, the
honest but trading patentee, the more completely to secure a
monopoly, often takes out several separate patents for nearly the
same thing in different forms, some avowedly worthless. In doing
this, without even intending it, he includes combinations, any
beneficial application of which perhaps never crossed his mind, and
which, in the shape in which he suggested them were good for
nothing, but which nevertheless more or less prevent anybody else
from touching them, even to make a good thing.
Again, the most respectable houses take out patents merely to
secure a monopoly of some one form of article without much regard
to the superiority of it. The result of all this is that it is
almost impossible now to introduce the slightest real improvement
in anything without infringing upon some patent, and exposing
oneself to be proceeded against by some patentee.
The extent to which improvements are impeded by this state of
things is hardly conceivable, except to those who, like myself, are
daily suffering under it.
There is another very serious evil produced by the system. In
taking out a patent, the necessity for avoiding all claim to
anything that can be shown to have been patented or in common use
before compels you in most cases to seek rather what part of it can
best be patented than what it is that is good in the invention.
Comparatively trivial points are frequently patented in order to
secure the monopoly of that which, although it constitutes the
merit of the invention, may not happen to be so new in every
respect as to admit of a patent. When the patent is taken, other
modes of carrying out the real invention are discovered; these
modes are patented and the original patentee is obliged to lose the
benefit of his invention or to buy up these new patents. There are
instances where enormous sums have been spent in this manner to
protect an original invention.
And, lastly, there is an evil which acts like a numbing disease on
all improvements; a patentee frequently dares not himself introduce
improvements in any apparatus or process which he has patented, for
fear of thus injuring his patent; and I have seen numerous cases of
very important inventions where all improvement has been thus
checked and resisted by the very parties most capable of effecting
them, and who would have brought great talent and zeal to the work
if they had been free.
_Extract from Observations on the Patent Laws made by Mr. Brunel at a
Meeting of the Society of Arts._
March 28, 1856.
He did not agree at all as to the advantages of patents. He quite
agreed as to the desirability of protecting, as far as possible, a
man’s property, whether it was in the power of invention, or any
other good thing that was within him, and still more would he
protect in every possible way the property in inventions of those
who possessed but little other property--the powers of the inventor
and the ingenuity of the workman; but, having had some considerable
experience with patentees, manufacturers, and workmen, he was of
opinion that any practical benefits derived from the patent laws
did not compensate for the injury inflicted. He believed, on the
contrary, that both the inventors and the public greatly suffered
from the attempt to protect inventions. He had had great experience
on this subject, being compelled daily to examine inventions of
various kinds, and having himself constantly to invent in the
occupations in which he was engaged. Having, then, all his life,
been connected with inventors and workmen, he had witnessed the
injury, the waste of mind, the waste of time, the excitement of
false hopes, the vast waste of money, caused by the patent laws, in
fact, all the evils which generally resulted from the attempt to
protect that which did not naturally admit of protection. He agreed
as to the abstract desirability of protecting inventors in some
way, provided it did not foster unhealthy invention, as he thought
it desirable to protect every species of property that existed. He
was disposed to encourage every step towards facilitating the
obtaining patents; he hoped they would be made dirt cheap, as he
thought that would be the most effectual way of destroying them
altogether. Therefore, whenever he had been consulted on the
subject of the patent laws, he had always advocated the rendering
of patents as open and free and cheap as possible; in the first
place, because he saw no reason for attaching a price to them, and
next, because they would sooner arrive where the principle would be
fully tested. We were already nearly arrived at that state of
things when engineers were almost brought to a dead stand in their
attempt to introduce improvements, from the excess of protection.
He found that he could hardly introduce the slightest improvement
in his own machinery without being stopped by a patent. He could
mention a striking instance, in which, a few months ago, wishing to
introduce an improvement that he thought would have been valuable
to the public in a large work on which he was engaged, he had no
sooner entered upon it, with a willingness to incur considerable
expense in the preliminary requirements and in the trial of it,
than he was stopped by a patentee; but he was fortunate enough to
find that another patent existed of the same thing, and a week
after a third appeared. There was thus, fortunately, a probability
that, by the destruction of all value in any of the patents, he
might be able to continue the improvements he was desirous of
introducing.
CHAPTER XVII.
_PRIVATE LIFE._
REMINISCENCES OF MR. BRUNEL’S PRIVATE LIFE--REMOVAL TO 18 DUKE
STREET, WESTMINSTER--HIS MARRIAGE, 1836--SPECIAL CONSTABLE IN
1848--MR. BRUNEL’S LOVE OF ART--HIS JOURNEY TO ITALY,
1842--ACCIDENT WITH THE HALF-SOVEREIGN, 1843--PURCHASE OF PROPERTY
IN DEVONSHIRE, 1847--HIS LIFE AT WATCOMBE--THE LAUNCH OF THE ‘GREAT
EASTERN,’ 1857--MR. BRUNEL’S FAILING HEALTH--JOURNEYS TO
SWITZERLAND AND EGYPT, 1858--LETTER FROM PHILÆ (FEBRUARY 12,
1859)--HIS LAST ILLNESS--HIS DEATH (SEPTEMBER 15,
1859)--FUNERAL--ADDRESS OF JOSEPH LOCKE, ESQ., M.P., AT THE
INSTITUTION OF CIVIL ENGINEERS (NOVEMBER 8, 1859).
Under any circumstances, and by whomsoever made, the attempt to describe
Mr. Brunel’s home life must fail to satisfy those who knew him, and who
remember him in the midst of his family or among his friends.
But those who did not know him, except as a professional man, or who are
only acquainted with his works, will expect to find in these pages some
account of his private life, and of the manner in which he spent those
brief intervals of relaxation which he permitted himself to enjoy.
* * * * *
Although Mr. Brunel was never an idle man, he was able, until he
obtained business on his own account, to enjoy many amusements from
which in after life he was completely debarred.
This arose partly from his work under his father being near his own home
and his friends, and partly from the power he possessed, and which never
deserted him, of being able to throw aside cares and anxieties and to
join with the utmost zest in passing amusements.
The following letter, relating to this time, is written by one who was
Mr. Brunel’s constant companion during the period to which it refers:--
June 28, 1870.
‘Dear Isambard Brunel,--I will endeavour to supply you with some
reminiscences of your father, before he became a public man, and
was engrossed by the very severe labour of his profession.
‘The most striking feature in his character as a young man, and one
which afterwards produced such great results, was an entire
abnegation of self in his intercourse with his friends and
associates.
‘His influence among them was unbounded, but never sought by him;
it was the result of his love of fair play, of his uniform kindness
and willingness to assist them, of the confidence he inspired in
his judgment, and of the simplicity and high-mindedness of his
character.
‘From 1824 to 1832 he joined his friends in every manly sport; and
when, after his accident at the Tunnel, he was obliged to withdraw
from more violent exercise, he was still ready to co-operate in the
arrangements required to give effect to whatever was in hand.
‘Whether in boating, in pic-nic parties, or in private theatricals,
he was always the life and soul of the party; for his skilful
arrangements, as well as his never-failing invention and power of
adaptation of whatever came to hand, made him the invariable leader
in every amusement or sport in which he took part.
‘To ensure the success of his friends in a rowing match against
time, from London to Oxford and back, in 1828, he designed and
superintended the building of a four-oared boat, which, in length
and in the proportion of its length to its breadth, far exceeded
any boat of the kind which had then been seen on the Thames.
‘During that portion of the period to which these notes refer, when
your father was engaged at the Tunnel works, the freshness and
energy with which he joined in the amusements of his friends after
many consecutive days and nights spent in the Tunnel--for
frequently he did not go to bed, I might almost say, for weeks
together--surprised them all.
‘His power of doing without sleep for long intervals was most
remarkable. He also possessed the power, which I have never seen
equalled in any other man, of maintaining a calm and even temper,
never showing irritation even when he was bearing an amount of
mental and bodily fatigue which few could have sustained. His
presence of mind and courage never failed him, and it was
especially exhibited after the first irruption of water into the
Tunnel, when he descended in the diving-bell to examine the extent
of the disturbance of the bed of the river, and the injury, if any,
which had been done to the brickwork.
‘The bell could not be lowered deep enough, and he dropped himself
out of the bell, holding on by a rope, and ascertained by careful
examination that the brickwork was uninjured.
‘He was several minutes in the water; and upon this fact being
stated, many persons, and I think the officers of the Royal Humane
Society, denied the possibility of his retaining his consciousness
so long in the water, forgetting, which he did not, that his lungs
were filled with air at two and a half atmospheres’ pressure.
‘In 1830, he joined the Surrey Yeomanry and attended drill, and was
out with the troop to which he belonged on several occasions.
‘In this capacity he was as popular as in every other; but his
remarkable talent in obtaining personal influence, even among those
with whom he was comparatively a stranger, was about this time most
usefully exhibited during the election of his brother-in-law as
member for Lambeth.
‘He made friends and conciliated opponents among all classes of
electors--especially among working men, large bodies of whom he met
on several occasions--and among all shades of politicians; and to
his energy, good judgment and skilful arrangement of electioneering
details, which were not then so well understood as they now are,
very much of the success achieved was due.
‘No one, I believe, ever saw him out of temper or heard him utter
an ill-natured word. He often said that spite and ill-nature were
the most expensive luxuries in life; and his advice, then often
sought, was given with that clearness and decision, and that
absence of all prejudice, which characterised his opinions in
after-life.
‘All his friends of his own age were attached to him in no ordinary
degree, and they watched every step in his future career with pride
and interest.
‘In fact, he was a joyous, open-hearted, considerate friend,
willing to contribute to the pleasure and enjoyment of those about
him; well knowing his own power, but never intruding it to the
annoyance of others, unless he was thwarted or opposed by
pretentious ignorance; and then, though at times decided and severe
in his remarks, he generally preferred leaving such individuals to
themselves, rather than, by noticing them, to give prominence to
their deficiencies.
‘His appreciation of character was so exact, and his dislike to
anything approaching to vulgarity in thought or action or to undue
assumption was so decided, that to be his friend soon became a
distinction; and the extent to which his society was sought, not
only in private life, but in the scientific world, at this early
period, marked strongly the distinguishing features of his mind and
character.
‘In 1825 and 1826 he attended the morning lectures at the Royal
Institution, and the eagerness and rapidity with which he followed
the chemical discoveries which were then being made by Mr. Faraday,
showed the facility with which he gained and retained scientific
knowledge.
‘To write more would lead me to the events of a later period of his
life, in the history of which you require no aid from me;
nevertheless, I cannot refrain from adding a few words upon your
father’s personal and professional character, which was not, in my
opinion, adequately appreciated by the public.
‘His professional friends before his death, and his private friends
at all times, well knew the genius, the intense energy, and
indefatigable industry with which every principle and detail of his
profession was mastered; and both knew and valued the high moral
tone which pervaded every act of his life.
‘The public, however, did not see him under the same circumstances.
‘Their imperfect acquaintance with his character arose in a great
degree from his disregard of popular approbation, for he was never
so satisfied with his own work as to feel himself entitled to
receive praise in the adulatory style of modern writing, and he
preferred to work quietly in his own sphere, and to rely on the
intrinsic merits of his undertakings bringing their reward, rather
than to court temporary popularity.
‘The rapidity with which he gained a high position as a civil
engineer is the best evidence of his talents. He passed almost
direct from boyhood to an equality with any one then in the
profession--a position attained by the rapidity and accuracy with
which he could apply theory to practice, and support his
conclusions by mathematical demonstrations.
‘This knowledge, always used without ostentation, soon placed him
above most of his contemporaries; and his intimate acquaintance
with the strength and peculiarities of the various materials he had
to employ, and of the best and most economical mode of applying
them, impressed both directors and contractors with a degree of
confidence in his estimates and opinions which no one had before
possessed.
‘His power of observation was singularly accurate; he was not
satisfied with a hasty or superficial examination, nor with the
mere assertion of a fact; his mind required evidence of its
correctness before he could receive and adopt it. I may illustrate
this by a reference to the experiments he made with French
mesmerists, and the pains he took to expose the farce of
table-turning and its accompanying follies.
‘My object, however, by this addition to my note, is to dwell upon
the fact that he left a mark upon his profession which cannot be
obliterated. He set up a high standard of professional excellence,
and endeavoured to impress on all who were associated with him, or
under him professionally, that to attain the highest honours
required the strictest integrity, sound mathematical knowledge,
originality and accuracy of thought and expression, both in _viva
voce_ descriptions and in designs and working drawings, and a
practical acquaintance with the durability and strength of
materials, so as to know the best conditions under which each might
be applied.
‘It was his excellence in these respects, when still young, which
soon earned for him a great reputation as a witness before the
Committees of the Houses of Parliament.
‘His calmness and unobtrusive manner, when under severe
examination, or while attending public meetings, led many to think
him cold, and regardless of the feelings or interests of those with
whom he was associated; but nothing was further from his character,
as every one knew who was engaged in the consultations upon the
result of which future proceedings depended.
‘He was a prudent and cautious, but bold adviser, and a
warm-hearted and generous friend.
‘Yours faithfully,
‘W. HAWES.
‘Isambard Brunel, Esq.’
The events of the year 1835 brought with them, not unnaturally, other
changes. At the beginning of 1836, he removed to 18 Duke Street,
Westminster, a large house looking on St. James’s Park, and now (1870)
the last in the street, next to the new India Office.
In July of the same year he married the eldest daughter of the late
William Horsley, and granddaughter of Doctor Callcott. Of this marriage
there was issue two sons and a daughter, all of whom survive him.
Although, as will be presently mentioned, he afterwards bought some
property in Devonshire, the Duke Street house was always his home. He
spent his life there, having his offices on the lower floors.
He had no wish to enter Parliament, although it had been more than once
suggested to him to do so, and his work prevented his taking an active
share, as an inhabitant of Westminster, in the concerns of his
neighbourhood.
The only occasion on which he took a prominent part in local affairs
was as a special constable in April 1848, when he acted as one of the
two ‘leaders’ of the special constables in the district between Great
George Street and Downing Street.
He was not without experience of the duties of a special constable, as
he had been sworn in during the Bristol riots of 1830, and on that
occasion saw active service. Happily, matters were better managed in
London, and no actual collision took place between the constables, or
the military, and the mob.
* * * * *
The extent to which Mr. Brunel kept his works in his own hands, and
under his own superintendence, made it necessary for him to have a large
amount of office accommodation; and the inconvenience of having branch
offices in the streets near his house led him, in 1848, to enlarge his
offices: with this object he added the adjoining house, 17 Duke Street,
which he rebuilt. A large room on the ground floor, looking on the Park,
was thenceforward his own office, and the room above was made the
dining-room. It was decorated in the Elizabethan style, and was to have
contained a collection of pictures illustrative of scenes in
‘Shakespeare,’ painted for him by the principal artists of the day. This
project was never completely carried out, but several pictures (about
ten in all) were painted and hung up, among them the ‘Titania’ of Sir
Edwin Landseer. These subjects are again referred to in the following
letter:--
February, 1870.
‘My dear Isambard,--You ask me to jot down for you any
reminiscences I have of your father’s love and feeling for art.
‘I remember with singular distinctness the first time I ever saw
him, when I was a lad of fourteen, and had just obtained my
studentship at the Royal Academy. He criticised with great keenness
and judgment a drawing which I had with me, and at the same time
gave me a lesson on paper straining. From that time till his death
he was my most intimate friend. Being naturally imbued with
artistic taste and perception of a very high order, his critical
remarks were always of great value, and were made with an amount of
good humour which softened their occasionally somewhat trying
pungency. He had a remarkably accurate eye for proportion, as well
as taste for form. This is evinced in every line to be found in his
sketch books, and in all the architectural features of his various
works.
‘So small an incident as the choice of colour in the original
carriages of the Great Western Railway, and any decorative work
called for on the line, gave public evidence of his taste in
colour; but those who remember the gradual arrangement and fitting
up of his house in Duke Street will want no assurance from me of
your father’s rare artistic feeling. He passed, I believe, the
pleasantest of his leisure moments in decorating that house, and
well do I remember our visits in search of rare furniture, china,
bronzes, &c., with which he filled it, till it became one of the
most remarkable and attractive houses in London. Its interest was
greatly increased when he formed that magnificent dining-room, now,
with the house of which it was a part, pulled down. This room, hung
with pictures, with its richly carved fireplace, doorways, and
ceiling, its silken hangings and Venetian mirrors, lighted up on
one of the many festive gatherings frequent in that hospitable
house, formed a scene which none will forget who had the privilege
of taking part in it. When from time to time he went abroad, and
especially in his visit to Venice in 1852, he added to his
collection by purchases made with great judgment and skill. In
buying pictures, your father evinced a taste often found in men of
refined mind and feeling--viz. a repugnance to works, however
excellent in themselves, where violent action was represented. He
preferred pictures where the subject partook more of the suggestive
than the positive, and where a considerable scope was left in which
the imagination of the spectator might disport itself. This feeling
was displayed in a great love of landscape art, and in the keenest
appreciation of the beauties of nature. It is an interesting fact
to record, and one which I often heard him mention, when his
friends were admiring his beautiful grounds at Watcombe, that in
the old posting days, when travelling on the cliff road between
Teignmouth and Torquay, he constantly stopped the carriage to get
out and admire the view which he had discovered from a field at
Watcombe, little thinking then that it would ultimately be the site
of his intended country home.
‘When your father and I went to Italy together in 1842, posting
from Westminster to Rome and back again, I had ample opportunities
of observing his love and enthusiasm for nature and art.
‘Overwhelmed as he was with work in England at the time, it was no
easy matter for him to leave the country for a couple of months;
and I remember that our starting at all was uncertain up to the
last moment; and that, an hour before quitting London, it was only
by a _coup de théâtre_, which he most adroitly performed, that he
escaped the serving of a subpœna, the bearer of which had
actually penetrated to the dining-room door in Duke Street.
‘We left London one evening in April 1842. During our journey we
constantly passed several consecutive days and nights in the
carriage; and I am sure there was not one of our waking hours in
which some incident of interest did not occur.
‘I remember your father agreeing with me, that our experiences
merely of post-boys and their various characteristics would be
worthy of recording in detail--from Newman’s two smart lads, who
took us the first stage out of London, on to the genuine
“postillon” (boots and all) we found at Calais; then to the wild
young brigands (in appearance) who, inspired by the prospect of
extra “buon mano,” whirled us along the road from Civita Vecchia
towards Rome, and winding up with the stolid German who rose slowly
in his stirrups, and distracted us by a melancholy performance on
the horn slung round him, and which no entreaty would induce him to
give up.
‘We posted from Calais, _viâ_ Paris, to Châlons-sur-Saône,
marvelling the whole way whereabouts “La Belle France” was to be
found; for a drearier and more utterly monotonous ride of something
like 800 miles it is impossible to conceive. From Châlons we went
down the river to Lyons, then onwards, visiting Nismes, and through
Arles to Toulon.
‘From Toulon we went through Cannes and Nice and along the lovely
Cornice road to Genoa. Your father was intensely delighted with
this portion of the journey. Those wonderfully picturesque towns,
with their roccoco churches looking like toys, and painted all over
upon the principle of colour generally developed in that species of
art, especially interested him. The streets were so narrow that it
was sometimes doubtful whether the carriage could be squeezed
through, and more than once it grazed the houses on either side as
it passed on.
‘The work for which your father had come to Italy commenced at
Genoa, and he was met there by a staff appointed by the Government
to accompany him during his stay.
‘While at Genoa he came to me one morning and said, that, in
consequence of some delay, he had a week in which to make complete
holiday, and gave me the choice of Florence or Rome. I need
scarcely say that I chose Rome, and for three days we were in the
Eternal City, seeing more in that time than those to whom we
related our proceedings could believe.
‘How well do I remember our entering Rome by the gate on the Civita
Vecchia road, and standing up in the carriage to get our first view
of St. Peter’s, and, having seen it, the blank look of
disappointment we turned on each other at the sight! But the
interior of the great church as far exceeded our expectations as
the exterior had fallen short of them.
‘We were back at Genoa to the minute your father had appointed; and
the work being completed there, we went on to Turin. Here we were
in time to be present at the Court balls and ceremonies consequent
upon the marriage of the present King of Italy.
‘From Turin we proceeded to Milan.
‘At Milan your father parted from his staff, and completed the work
he had undertaken as far as it was necessary to do so in Italy.
From Milan, therefore, our journey home was one of uninterrupted
enjoyment through those glorious Lombard towns to Venice, which
happily we reached in a gondola from Mestre, and not by a railway
viaduct; then through the Tyrol to Munich, and so down the Rhine to
Belgium, reaching home from Antwerp.
‘Thus was completed an expedition in which there was neither hitch
nor disagreeable adventure of any kind, and upon which I look back
with unmixed pleasure.
‘The next and last time that your father and I journeyed on the
Continent together was in April 1848, when he wished to see Paris
in Republican garb, and asked me to accompany him.
‘We were there for some days, and, armed with cards of admission,
on which our names were inscribed with the prefix of “Citoyen,”
heard and saw the various celebrities of the hour.
‘Affectionately yours,
J. C. HORSLEY.
‘Isambard Brunel, Esq.’
Within less than a year of Mr. Brunel’s return from his visit to Italy,
a strange accident happened to him, which placed his life in great
jeopardy.
On April 3, 1843, he was amusing some children at his house by the
exhibition of conjuring tricks, when, in pretending to pass a
half-sovereign from his ear to his mouth, the coin he had placed in his
mouth slipped down his throat. After a few days he began to suffer from
a troublesome cough, and on April 18 Sir Benjamin Brodie was consulted.
The nature of the accident and the course of treatment adopted are
described in the following letter from Mr. Brunel’s brother-in-law, the
late Dr. Seth Thompson, which was published in the ‘Times’ newspaper of
May 16, 1843:--
I shall be much obliged by your giving insertion to the following
statement of the treatment pursued by Sir Benjamin Brodie in the
case of Mr. Brunel, it being the wish of Mr. Brunel and his friends
that the true facts should be known, as a just tribute to the skill
of this eminent surgeon, and as a guide to future practice. The
accident happened on April 3; Sir B. Brodie was consulted on the
18th, and his opinion was that the half-sovereign had passed into
the windpipe. The following day Mr. Brunel strengthened this
opinion by a simple experiment. He bent his head and shoulders over
a chair, and distinctly felt the coin drop towards the glottis;
whilst raising himself a violent fit of coughing came on, which
ceased after a few minutes. He repeated this a second time, with
the same results. A consultation was held on the 22nd, at which it
was decided that conclusive evidence existed of the half-sovereign
having passed into the windpipe, that it was probably lodged at the
bottom of the right bronchus, and that it was movable. It was
determined that every effort should be made for its removal, and
that for this purpose an apparatus should be constructed for
inverting the body of the patient, in order that the weight of the
coin might assist the natural effort to expel it by coughing. The
first experiment was made on the 25th. The body of the patient
being inverted, and the back gently struck with the hand between
the shoulders, violent cough came on, but of so convulsive and
alarming a nature that danger was apprehended, and the experiment
was discontinued. On this occasion the coin was again moved from
its situation, and slipped towards the glottis. On the 27th
tracheotomy was performed by Sir B. Brodie, assisted by Mr. Aston
Key, with the intention of extracting the coin by the forceps, if
possible, or, in the event of this failing, with the expectation
that the opening in the windpipe would facilitate a repetition of
the experiment of the 22nd. On this occasion, and subsequently on
May 2, the introduction of the forceps was attended with so much
irritation, that it could not be persevered in without danger to
life. On the 3rd another consultation was held, when Mr. Lawrence
and Mr. Stanley entirely confirmed the views of Sir B. Brodie and
Mr. Key, and it was agreed that the experiment of inversion should
be repeated as soon as Mr. Brunel had recovered sufficient
strength, the incision in the windpipe being kept open. On
Saturday, the 13th, Mr. Brunel was again placed on the apparatus,
the body inverted, and the back gently struck. After two or three
coughs, he felt the coin quit its place on the right side of the
chest, and in a few seconds it dropped from his mouth without
exciting in its passage through the glottis any distress or
inconvenience, the opening in the windpipe preventing any spasmodic
action of the glottis.
In this remarkable case the following circumstances appear to be
worthy of note--that a piece of gold remained in the air-tube for
six weeks, quite movable, and without exciting any inflammatory
action, the breathing entirely undisturbed, and the only symptoms
of its presence occasional uneasiness on the right side of the
chest and frequent fits of coughing; that an accurate diagnosis was
formed without being able to obtain any assistance from the
stethoscope, although the chest was repeatedly and carefully
examined; and also that, a fair trial having been given to the
forceps, the application of this instrument to the removal of a
body of this peculiar form from the bottom of the bronchus was
proved to be attended with great risk to life, while the cautious
and well-considered plan of treatment above detailed was attended
with complete success, and without risk.
During the time that Mr. Brunel was in danger the public excitement was
intense. His high professional position, the extraordinary nature of the
accident, and the greatness of the loss, were the result to prove fatal,
made his condition and the chances of his recovery an engrossing topic
of conversation; and, when the news was spread that ‘it is out,’ the
message needed no explanation.
That the result was successful was due, not only to the skill of the
surgeons engaged, and to the anxious care with which those who nursed
him left nothing undone to ensure his safety, but also to the remarkable
coolness which Mr. Brunel himself displayed throughout. From the first
he took part in the consultations which were held on his case, and
assisted materially in determining the course of treatment which should
be pursued.
* * * * *
The ten years which followed were the most prosperous in Mr. Brunel’s
life; he had attained to great eminence in his profession, and was still
in the enjoyment of robust health. But the results of the gauge
controversy and the fierce contests which followed it, and, above all,
the failure of the Atmospheric System on the South Devon Railway, caused
him grave anxiety and sorrow. Critics have erred greatly in representing
him as a man who, in order to accomplish some vast design, thought but
little of the distress which follows want of success in commercial
enterprises. So far from its being true that Mr. Brunel was indifferent
to the interests of his employers, his private journals show that
throughout (to use his own words) ‘the incessant warfare in which he was
engaged’ he was earnestly desiring peace and endeavouring to secure it,
and that in times of difficulty, such as the trial of the Atmospheric
System and the launch of the ‘Great Eastern,’ his chief thoughts were
for those who would suffer through the failure of his plans.
* * * * *
In the midst of his professional occupations he was able occasionally,
though rarely, to enjoy the society of his friends. After the session
was over, in 1844 and 1845, he went to Italy on business, and in 1846 to
Switzerland for a short holiday. In 1847 the South Devon Railway was
occupying his attention, and he determined to take a house at Torquay.
While there, the important character of his railway works in Devonshire
and Cornwall led him to think of making a more permanent settlement in
that part of the country.
After a good deal of hesitation between various places, he fixed upon a
spot at Watcombe, about three miles from Torquay, on the Teignmouth
turnpike road. He made his first purchase of land in the autumn of 1847;
and from that time to within a year of his death the improvement of this
property was his chief delight.
He had always a great love and appreciation of beautiful scenery, and in
his choice of a place in which to plant and build he provided amply for
his complete gratification.
The principal view, which, if the house had been built, would have been
the view from the terrace, is one of the loveliest in that part of
Devonshire. On one side is the sea, and on the other the range of
Dartmoor, while in front is spread undulating country, bounded by the
hills on the further side of Torbay, the bay itself looking like a lake,
being shut in by the hills above Torquay.
When Mr. Brunel bought this property it consisted of fields divided by
hedgerows; but, assisted by Mr. William Nesfield, he laid it out in
plantations of choice trees. The occupation of arranging them gave him
unfailing pleasure; and, although he could seldom spare more than a few
days’ holiday at a time, there can be little doubt that the happiest
hours of his life were spent in walking about in the gardens with his
wife and children, and discussing the condition and prospects of his
favourite trees.[193]
He could not, of course, take a prominent part in the affairs of the
parish, but he was always ready to assist in any work that had been
taken in hand. He will be long remembered there by his friends in every
rank of life.
In purchasing this property in Devonshire, Mr. Brunel had looked forward
to retiring gradually from active professional life, ‘to draw in and
make room for others,’ and to spend a greater portion of his time in the
country.
It may well be questioned whether he would have been happy in giving up
work while yet in middle life; but the wisdom of his resolve was not to
be put to the test.
From the beginning of the year 1852 the ‘Great Eastern’ steam-ship began
to occupy his time and thoughts. As the works progressed he was more and
more tied to London; and the large pecuniary investment he had made in
the shares of the company caused him to hesitate before proceeding with
the building of his house.
Thus the hopes he had formed for making his home in Devonshire faded
gradually away, and were at length extinguished by the failure of his
health.
* * * * *
Many things had happened in the earlier part of 1857 which gave him
pleasure. In June he received, in company with Mr. Robert Stephenson,
the honorary degree of Doctor in Civil Law from the University of
Oxford.[194] In the summer he paid several visits to Devonshire, and at
the beginning of September the floating of the first truss of the
Saltash bridge was successfully accomplished.
The history of the launch of the ‘Great Eastern,’ which was commenced in
November, has been already told. Throughout all the disappointments he
then endured Mr. Brunel took comfort from the sympathy of valued
friends, and from those higher sources of consolation on which it was
his habit to rely. He paid for his exertions a heavy price, for they
left him broken in health and already suffering from the disease of
which in a little more than eighteen mouths afterwards he died.[195]
* * * * *
In May 1858 Mr. Brunel went to Vichy, and thence to Switzerland,
returning home in the autumn by way of Holland. When at Lucerne he went
up the Righi, and was so charmed with it that, instead of spending only
a night there, he remained a week, working at the designs for the
Eastern Bengal Railway.
It was on his return to England in September that the alarming nature of
his illness was ascertained. After anxious consultation with Sir
Benjamin Brodie and Dr. Bright, he was ordered to spend the winter in
Egypt, in the hope that he might return in the March or April following
in restored health.
He was very unwilling to be so long absent from England, especially as a
new company had just been formed to finish the ‘Great Eastern,’ and the
contracts for her completion were about to be let.
However, it was thought that very serious consequences might follow if
he remained at home; and in the beginning of December he left for
Alexandria, with his wife and younger son.
Having stayed there a day or two, they went on to Cairo, where they
found Mr. Robert Stephenson. He and Mr. Brunel dined together on
Christmas Day.
On December 30 the journey up the Nile commenced. On January 21 they
arrived at Thebes, and spent some days there. Mr. Brunel was able to
ride about on a donkey, and made some sketches of the celebrated ruins
in the neighbourhood.[196]
They reached Assouan on February 2, and made preparations for ascending
the cataracts. They went as far as Dakkeh, and got back to Assouan on
February 19.
The following letter from Mr. Brunel to his sister, Lady Hawes,
describes some of the scenes through which he passed:--
Philæ, February 12, 1859.
I now write to you from a charming place; but Assouan, which I
left to come here, is also beautiful, and I will speak of that
first. It is strange that so little is said in the guide books of
the picturesque beauty of these places. Approaching Assouan, you
glide through a reef of rocks, large boulders of granite polished
by the action of the water charged with sand. You arrive at a
charming bay or lake of perfectly still water and studded with
these singular jet-black or red rock islands. In the distance you
see a continuation of the river, with distant islands shut in by
mountains, of beautiful colours, some a lilac sandstone, some the
bright red yellow of the sands of the desert. Above the
promontories the water excursions are delicious. You enter at once
among the islands of the Cataracts, fantastic forms of granite
heaps of boulders split and worn into singular shapes.
After spending a week at Assouan, with a trip by land to Philæ, I
was so charmed with the appearance of the Cataracts as seen from
the shore, and with the deliciously quiet repose of Philæ, that I
determined to get a boat, and sleep a few nights there. We
succeeded in hiring a country boat laden with dates, and emptied
her, and fitted up her three cabins.[197] We put our cook and
dragoman and provisions, &c., on board, and some men, and went up
the Cataract. It was a most amusing affair, and most beautiful and
curious scenery all the way. It is a long rapid of three miles, and
perhaps one mile wide, full of rocky islands and isolated rocks. A
bird’s-eye view hardly shows a free passage, and some of the more
rapid falls are between rocks not forty feet wide--in appearance
not twenty. Although they do not drag the boats up perpendicular
falls of three or four feet, as the travellers’ books tell you,
they really do drag the boats up rushes of water which, until I had
seen it, and had then calculated the power required, I should
imprudently have said could not be effected. We were dragged up at
one place a gush of water, what might fairly be called a fall of
about three feet, the water rushing past very formidably, and
between rocks seemingly not more than wide enough to let our boat
pass, and this only by some thirty-five men at three or four ropes,
the men standing in the water and on the rocks in all directions,
shouting, plunging into the water, swimming across the top or
bottom of the fall, just as they wanted, then getting under the
boat to push it off rocks, all with an immense expenditure of noise
and apparent confusion and want of plan, yet on the whole properly
and successfully. We were probably twenty or thirty minutes getting
up this one, sometimes bumping hard on one rock, sometimes on
another, and jammed hard first on one side and then on the other,
the boat all the time on the fall with ropes all strained,
sometimes going up a foot or two, sometimes losing it, till at last
we crept to the top, and sailed quietly on in a perfectly smooth
lake. These efforts up the different falls had been going on for
nearly eight hours, and the relief from noise was delicious. We
selected a quiet spot under the temples of Philæ.... Our
poultry-yard is on the sandbank, where fowls, pigeons, and turkeys
are walking about loose, and, like all animals in this country,
perfectly tame. Yes, they walk up and catch a pigeon to be killed
when you like. In the midst of these and of the small birds which
always walk and fly about us, have been walking for hours this
morning three or four large eagles, who, with the politeness
peculiar to animals here, pay no attention to our fowls, nor do
they to the eagles. But here I am entering on the anomalies and
contradictions of Egypt, which would fill volumes.
After leaving Egypt, Mr. Brunel went to Naples and Rome, where he spent
Easter, and he returned to England in the middle of May.
When abroad, Mr. Brunel made sight-seeing a pleasure rather than a
business; thus in Egypt he preferred to visit frequently the same
places, and rather to enjoy that which he knew gave him pleasure, than
to hurry about with the object of seeing all that was to be seen. At
Philæ he stopped more than a week, and at Thebes he spent more time in a
small outlying temple near Karnac than in the great ruin itself. So also
at Rome he went frequently to the Colosseum, and he spent many hours in
the interior of St. Peter’s.
Shortly after his return to England he went to Plymouth, and over the
Saltash bridge and other parts of the Cornwall Railway, which had been
opened during his absence abroad.
Although it had by this time become certain that the disease under which
he laboured had assumed a fatal character, he continued to give
unremitting attention to his various professional duties; and in order
to be nearer the ‘Great Eastern,’ he took a house at Sydenham, and
removed there with his family in the beginning of August.
Almost every day he went to the great ship and superintended the
preparations for getting her to sea. She was advertised to sail on
September 6, and Mr. Brunel had intended going round in her to Weymouth.
He was on board early on the morning of the 5th, and his memorandum book
has, under that date, an entry of some unfinished work which had to be
looked after. Towards midday he felt symptoms of failing power, and went
home to his house in Duke Street, when it became evident that he had
been attacked with paralysis.
* * * * *
At one time it seemed possible that he might recover; but on the tenth
day after his seizure, Thursday, September 15, all hope was taken away.
In the afternoon he spoke to those who watched around him, calling them
to him by their names; as evening closed in he gradually sank, and died
at half-past ten, quietly and without pain.
* * * * *
The funeral was on September 20, at the Kensal Green Cemetery.
Along the road leading to the chapel many hundreds of his private and
professional friends, his neighbours among the tradespeople of
Westminster, the Council of the Institution of Civil Engineers, and the
servants of the Great Western Railway Company, had assembled, and, with
his family, followed his body to its place of burial, in the grave of
his father and mother.[198]
It would be improper here to attempt to enter into a general criticism
of Mr. Brunel’s works, or to determine the position which he is entitled
to occupy among civil engineers. That task has yet to be accomplished,
and must be undertaken by those who can claim to be impartial judges. It
has been the object of this book to provide, as far as possible, the
materials on which a just judgment of his career can be based.
But it may be permitted, in conclusion, to place on record the following
testimony to the high position held by Mr. Brunel in the esteem of his
contemporaries.
* * * * *
On November 8, 1859, at the first meeting of the Institution of Civil
Engineers after the death of Mr. Brunel and of Mr. Robert Stephenson,
Mr. Joseph Locke, M.P., the President, rose and said--
‘I cannot permit the occasion of opening a new session to pass without
alluding to the irreparable loss which the Institution has sustained by
the death, during the recess, of its two most honoured and distinguished
members.
‘In the midst of difficulties of no ordinary kind, with an ardour
rarely equalled, and an application both of body and mind almost beyond
the limit of physical endurance, in the full pursuit of a great and
cherished idea, Brunel was suddenly struck down, before he had
accomplished the task which his daring genius had set before him.
‘Following in the footsteps of his distinguished parent, Sir Isambard
Brunel, his early career, even from its commencement, was remarkable for
originality in the conception of the works confided to him. As his
experience increased, his confidence in his own powers augmented; and
the Great Western Railway, with its broad-gauge line, colossal engines,
large carriages, and bold designs of every description, was carried
onward, and ultimately embraced a wide district of the country.
‘The same feeling induced, in steam navigation, the successive
construction of the “Great Western” steamer, the largest vessel of the
time, until superseded by the “Great Britain,” which was in its turn
eclipsed by the “Great Eastern,” the most gigantic experiment of the
age.
‘The Great Ship was Brunel’s peculiar child; he applied himself to it in
a manner which could not fail to command respect; and, if he did not
live to see its final and successful completion, he saw enough, in his
later hours, to sustain him in the belief that his idea would ultimately
become a triumphant reality.
‘The shock which the loss of Brunel created was yet felt, when we were
startled by an announcement that another of our esteemed members had
been summoned from us.[199]
* * * * *
‘It is not my intention at this time to give even an outline of the
works achieved by our two departed friends. Their lives and labours,
however, are before us; and it will be our own fault if we fail to draw
from them useful lessons for our own guidance. Man is not perfect, and
it is not to be expected that he should be always successful; and, as in
the midst of success we sometimes learn great truths before unknown to
us, so also we often discover in failure the causes which frustrate our
best directed efforts. Our two friends may probably form no exception to
the general rule; but, judging by the position they had each secured,
and by the universal respect and sympathy which the public has
manifested for their loss, and remembering the brilliant ingenuity of
argument, as well as the more homely appeals to their own long
experience, often heard in this hall, we are well assured that they have
not laboured in vain.
‘We, at least, who are benefited by their successes, who feel that our
Institution has reason to be proud of its association with such names as
Brunel and Stephenson, have a duty to perform; and that duty is, to
honour their memory and emulate their example.’
APPENDIX I.
(_See Chapter V. on the Broad Gauge, p. 99._)
_Report to the Board of Directors of the Great Western Railway Company._
August 1838.
GENTLEMEN,--As the endeavour to obtain the opinions and reports of Mr.
Walker, Mr. Stephenson, and Mr. Wood, prior to the next half-yearly
meeting, has not been successful, I am anxious to record more fully than
I have previously done, and to combine them into one report, my own
views and opinions upon the success of the several plans which have been
adopted at my recommendation in the formation and in the working of our
line; and in justice to myself and to these plans, and indeed to enable
others to arrive at any just conclusion as to the result which has been
attained, or as to the probable ultimate success or advantages of the
system, it is necessary that I should enter very fully, I fear even
tediously, into a recapitulation of the circumstances, peculiar to this
railway, which led to the consideration and the adoption of these plans,
which some call innovations and wide deviations from the results of past
experience, but the majority of which I will undertake to show are
merely adaptations of those plans to our particular circumstances.
It will be necessary also that I should refer to all the numerous
difficulties which we have had to encounter, which have necessarily
prevented the perfect working of these plans in the first instance, but
which have been overcome, or which are gradually and successively
diminishing; and, finally, I am prepared to show that, notwithstanding
the novelty of the circumstances, and the difficulties and delays which
at the outset invariably attend any alteration, however necessary, or
however desirable, from the accustomed mode of proceeding, and
notwithstanding the violent prejudices excited against us, and the
increased difficulties caused by these prejudices, the result is still
such as to justify the attempt which has been made, and to show that in
the main features, if not in all the details, the system hitherto
followed is good, and ought to be pursued.
The peculiarity of the circumstances of this railway, to which I would
more particularly refer, and which have frequently been mentioned,
consists in the unusually favourable gradients and curves which we have
been able to obtain. With the capability of carrying the line upwards of
fifty miles out of London on almost a dead level, and without any
objectionable curve, and having beyond this, and for the whole distance
to Bristol, excellent gradients, it was thought that unusually high
speed might easily be attained, and that the very large extent of
passenger traffic which such a line would certainly command would ensure
a return for any advantages which could be offered to the public, either
in increased speed or increased accommodations. With this view every
possible attention was paid to the improvement of the line as originally
laid down in the parliamentary plans. We ultimately succeeded in
determining a maximum gradient of 4 feet per mile, which could be
maintained for the unusual distance, before mentioned, of upwards of
fifty miles from London, and also between Bristol and Bath,
comprehending those parts of the line on which the principal portion of
the passenger traffic will be carried. The attainment of high speed
appeared to involve the question of the width of gauge, and on this
point accordingly I expressed my opinion at a very early period.
It has been asserted that 4 feet 8 inches, the width adopted on the
Liverpool and Manchester Railway, is exactly the proper width for all
railways, and that to adopt any other dimension is to deviate from a
positive rule which experience has proved correct; but such an assertion
can be maintained by no reasoning. Admitting, for the sake of argument,
that, under the particular circumstances in which it has been tried, 4
feet 8 inches has been proved the best possible dimension, the question
would still remain--What are the best dimensions under the
circumstances?
Although a breadth of 4 feet 8 inches has been found to create a certain
resistance on curves of a certain radius, a greater breadth would
produce only the same resistance on curves of greater radius. If
carriages and engines, and more particularly if wheels and axles of a
certain weight, have not been found inconvenient upon one railway,
greater weights may be employed and the same results obtained on a
railway with better gradients. To adopt a gauge of the same number of
inches on the Great Western Railway as on the Grand Junction Railway,
would in fact amount practically to the use of a different gauge in
similar railways. The gauge which is well adapted to the one is not well
adapted to the other, unless, indeed, some mysterious cause exists which
has never yet been explained for the empirical law which would fix the
gauge under all circumstances.
Fortunately this no longer requires to be argued, as too many
authorities may now be quoted in support of a very considerable
deviation from this prescribed width, and in every case this change has
been an increase. I take it for granted that, in determining the
dimensions in each case, due regard has been had to the curves and
gradients of the line, which ought to form a most essential, if not the
principal, condition.
In the Report of the Commissioners upon Irish Railways, the arguments
are identically the same with those which I used when first addressing
you on the subject in my Report of October 1835. The mechanical
advantage to be gained by increasing the diameter of the carriage-wheels
is pointed out, the necessity, to attain this, of increasing the width
of way, the dimensions of the bridges, tunnels, and other principal
works, not being materially affected by this; but, on the other hand,
the circumstance which limits this increase being the curves on the
line, and the increased proportional resistance on inclinations (and on
this account it is stated to be almost solely applicable to very level
lines); and, lastly, the increased expense, which could be justified
only by a great traffic.
The whole is clearly argued in a general point of view, and then applied
to the particular case, and the result of this application is the
recommendation of the adoption of 6 feet 2 inches on the Irish railways.
Thus, an increase in the breadth of way to attain one particular
object--viz. the capability of increasing the diameter of the
carriage-wheels without raising the bodies of the carriages--is admitted
to be most desirable, but is limited by certain circumstances, namely,
the gradients and curves of the line, and the extent of traffic.
Every argument here adduced, and every calculation made, would tend to
the adoption of about 7 feet on the Great Western Railway.
The gradients of the lines laid down by the Irish Commission are
considerably steeper than those of the London and Birmingham Railway,
and four and five times the inclination of those on the Great Western
Railway; the curves are by no means of very large radius, and indeed the
Commissioners, after fixing the gauge of 6 feet 2 inches, express their
opinion, that upon examination into the question of curves, with a view
to economy, they do not find that the effect is so injurious as might
have been anticipated, and imply therefore that curves, generally
considered of small radius on our English lines, are not incompatible
with the 6 feet 2 inch gauge; and, lastly, the traffic, instead of being
unusually large, so as to justify any expense beyond that absolutely
required, is such as to render assistance from Government necessary to
ensure a return for the capital embarked. As compared with this, what
are the circumstances in our case?
The object to be attained is the placing an ordinary coach body, which
is upwards of 6 feet 6 inches in width, between the wheels. This
necessarily involves a gauge of rail of about 6 feet 10½ inches to 6
feet 11 inches, but 7 feet allows of its being done easily; it allows,
moreover, of a different arrangement of the body: it admits all sorts of
carriages, stage-coaches, and carts to be carried between the wheels.
And what are the limits in the case of the Great Western Railway, as
compared to those on Irish railways? Gradients of one-fifth the
inclination, very favourable curves, and probably the largest traffic in
England.
I think it unnecessary to say another word to show that the Irish
Commissioners would have arrived at 7 feet on the Great Western Railway
by exactly the same train of argument that led them to adopt 6 feet 2
inches in the case then before them.
All these arguments were advanced by me in my first Report to you, and
the subject was well considered. The circumstance of the Great Western
Railway, and other principal railways likely to extend beyond it, having
no connection with other lines then made, leaving us free from any
prescribed dimension, the 7-feet gauge was ultimately determined upon.
Many objections were certainly urged against it: the deviation from the
established 4 feet 8 inches was then considered as the abandonment of
the principle: this, however, was a mere assertion, unsupported even by
plausible argument, and was gradually disused; but objections were still
urged, that the original cost of construction of all the works connected
with the formation of the line must be greatly increased; that the
carriages must be so much stronger; that they would be proportionally
heavier; that they would not run round the curves, and would be more
liable to run off the rails; and particularly, that the increased length
of the axles would render them liable to be broken: and these objections
were not advanced as difficulties which, as existing in all railways,
might be somewhat increased by the increase of gauge, but as peculiar to
this, and fatal to the system.
With regard to the first objection, namely, the increased cost in the
original construction of the line, if there be any, it is a question of
calculation which is easily estimated, and was so estimated before the
increased gauge was determined upon. Here, however, preconceived
opinions have been allowed weight in lieu of arguments and calculations;
cause and effect are mixed up, and without much consideration it was
assumed at once that an increased gauge necessarily involved increased
width of way, and dimensions of bridges, tunnels, &c.
Yet such is not the case within the limits we are now treating of: a
7-feet rail requires no wider bridge or tunnel than a 5-feet; the
breadth is governed by a maximum width allowed for a loaded waggon, or
the largest load to be carried on the railway, and the clear space to be
allowed on either side beyond this.
On the Manchester and Liverpool Railway this total breadth is only 9
feet 10 inches, and the bridge and viaducts need only have been twice
this, or 19 feet 8 inches; 9 feet 10 inches was found, however, rather
too small, and in the London and Birmingham, with the same width of way,
this was increased to 11 feet by widening the interval between the two
rails.
In the space of 11 feet, allowed for each rail, a 7-feet gauge might be
placed just as well as a 5-feet, leaving the bridges, tunnels, and
viaducts exactly the same; but 11 feet was thought by some still too
narrow: and when it is remembered that this barely allows a width of 10
feet for loads, whether of cotton, wool, agricultural produce, or other
light goods, and which are liable also to be displaced in travelling, 13
feet (which has been fixed upon in the Great Western Railway, and which
limits the maximum breadth, under any circumstances, to about 12 feet)
will not be found excessive.
It is this which makes the minimum width, actually required under
bridges and tunnels, 26 feet instead of 22 feet, and not the increased
gauge.
The earthwork is slightly affected by the gauge, but only to the extent
of 2 feet on the embankment, and not quite so much in the cuttings; but
what, in practice, has been the result? The bridges over the railway on
the London and Birmingham are 30 feet, and the width of viaducts 28
feet; on the Great Western Railway they are both 30 feet; no great
expense is therefore incurred on these items, and certainly a very small
one compared to the increased space gained, which, as I have stated, is
from 10 to 12 feet. In the tunnels exists the greatest difference; on
the London and Birmingham Railway, which I refer to as being the best
and most analogous case to that of the Great Western Railway, the
tunnels are 24 feet wide. On the Great Western Railway the constant
width of 30 feet is maintained, more with a view of diminishing the
objections to tunnels, and maintaining the same minimum space which
hereafter may form a limit to the size and form of everything carried on
the railway, than from such a width being absolutely necessary.
Without pretending to find fault with the dimensions fixed, and which
have, no doubt, been well considered, upon the works on other lines, I
may state that the principle which has governed has been to fix the
minimum width, and to make all the works the same, considering it
unnecessary to have a greater width between the parapet walls of a
viaduct, which admits of being altered, than between the sides of a
tunnel which cannot be altered.
The embankments on the London and Birmingham Railway are 26 feet, on the
Great Western 30 feet, making an excess of about six and a half per
cent. on the actual quantity of earthwork.
The difference in the quantity of land required is under half an acre to
a mile. On the whole, the increased dimensions from 10 to 12 feet will
not cause any average increased expense in the construction of the
works, and purchase of land, of above seven per cent.--eight per cent.
having originally been assumed in my Report in 1835 as the excess to be
provided for.
With respect to the weight of the carriages, although we have wheels of
4 feet diameter, instead of 3 feet, which, of course, involves an
increased weight quite independent of the increase of width, and
although the space allowed for each passenger is a trifle more, and the
height of the body greater, yet the gross weight per passenger is
somewhat less.
Tons cwt. qrs. lbs.
A Birmingham first-class coach weighs 3 17 2 0
Which with 18 passengers at 15 to the ton 1 4 0 0
----------------
5 1 2 0
Or 631 lbs. per passenger ================
A Great Western first-class weighs 4 14 0 0
And with 24 passengers 1 12 0 0
----------------
6 6 0 0
Or 588 lbs. per passenger ================
And our 6-wheeled first-class 6 11 0 0
With 32 passengers 2 2 2 0
----------------
8 13 2 0
Or 600 lbs. per passenger ================
Being an average of 594 lbs. on the two carriages.
This saving of weight does not arise from the increased width, and is
notwithstanding the increased strength of the framing and the increased
diameter and weight of the wheels; I have not weighed our second-class
open carriages, but I should think the same proportion would exist.
As to the breaking of axles or running off the line, the practical
result has been that, from some cause or other, we have been almost
perfectly free from those very objections which have been felt so
seriously on some other lines. Far from breaking any engine axles, not
even a single cranked axle has been strained, although the engines have
been subjected to rather severe trials. One of our largest having, a
short time back, been sent along the line at night, when it was not
expected, came in collision with some ballast waggons, and was thrown
off the line nearly 6 feet; none of the axles were bent, or even
strained in the least, although the front of the carriage, a piece of
oak of very large scantling, was shattered. After ten weeks’ running,
one solitary instance has occurred of a carriage in a train getting off
the line and dragging another with it, and which was not discovered till
after running a mile and a half. As the carriage was in the middle of
the train, and one end of the axle was thrown completely out of the axle
guard, there must evidently have been some extraordinary cause--possibly
a plank thrown across the railway by a blow from the carriage which
preceded, and which might have produced the same effect on any railway;
and at any rate it was a strong trial to the axle, which was not broken,
but merely restored to its place, and the carriage sent on to London.
The same mode of reasoning which has by some been used in favour of the
4 feet 8 inches gauge, if applied here, would prove that long axles are
stronger than short, and wide rails best adapted for curves. All that I
think proved, however, is this--that the increased tendency of the axles
to break, or of the wheels to run off the rails, is so slight that it is
more than counterbalanced by the increased steadiness from the width of
the base, and the absence of those violent strains which arise from
irregularity on the gauge and the harshness of the ordinary construction
of rails. In fact, not one of the objections originally urged against
the practical working of the wide gauge has been found to exist, while
the object sought for is obtained, namely, the capability of increasing
at any future period the diameter of the wheels, which cannot be done,
however desirable it may hereafter be found, with the old width of rail.
This may be said to be only prospective; but, in the meantime,
contingent advantages are sensibly felt in the increased lateral
steadiness of the carriages and engines, and the greater space which is
afforded for the works of the locomotives. And here I wish particularly
to call your attention to the fact that this prospective advantage--this
absence of a most inconvenient limit to the reduction of the friction,
which, with our gradients, forms four-fifths or eighty per cent. of the
total resistance--was the object sought for, and that, at the time of
recommending it, I expressly stated as follows:--‘I am not by any means
prepared at present to recommend any particular size of wheel, or even
any great increase of the present dimensions. I believe they _will_ be
materially increased; but my great object would be in every possible way
to render each part _capable_ of improvement, and to remove what appears
an obstacle to any great progress in such a very important point as the
diameter of the wheels, upon which the resistance, which governs the
cost of transport and the speed that may be obtained, so materially
depends.’
These advantages were considered important by you, they are now
considered so by many others; and certainly everything which has
occurred in the practical working of the line confirms me in my
conviction that we have secured a most valuable power to the Great
Western Railway, and that it would be folly to abandon it.
The next point I shall consider is the construction of the engines, the
modifications in which, necessary to adapt them to higher speeds than
usual, have, like the increased width of gauge, been condemned as
innovations.
I shall not attempt to argue with those who consider any increase of
speed unnecessary. The public will always prefer that conveyance which
is most perfect, and speed within reasonable limits is a material
ingredient in perfection in travelling.
A rate of thirty-five to forty miles an hour is not unfrequently
attained at present on other railways in descending planes, or with
light loads on a level, and is found practically to be attended with no
inconvenience. To maintain such a speed with regularity on a level line,
with moderate loads, is therefore quite practicable, and unquestionably
desirable. With this view the engines were constructed, but nothing new
was required or recommended by me.
A certain velocity of the piston is considered the most advantageous.
The engines intended for slow speeds have always had the driving wheels
small in proportion to the length of stroke of the piston. The faster
engines have had a different proportion; the wheels have been larger, or
the strokes of the piston shorter. From the somewhat clamorous
objections raised against the large wheels, and the construction of the
Great Western Railway engines, and the opinions rather freely expressed
of my judgment in directing this construction, it would naturally be
supposed that some established principle had been departed from, and
that I had recommended this departure.
The facts are, that a certain velocity of piston being found most
advantageous, I fixed this velocity, so that the engines should be
adapted to run thirty-five miles an hour, and capable of running
forty--as the Manchester and Liverpool Railway engines are best
calculated for twenty to twenty-five, but capable of running easily up
to thirty and thirty-five miles per hour; and fixing also the load which
the engine was to be capable of drawing, I left the form of construction
and the proportions entirely to the manufacturers, stipulating merely
that they should submit detail drawings to me for my approval. This was
the substance of the circular, which, with your sanction, was sent to
several of the most experienced manufacturers. Most of these
manufacturers, of their own accord, and without previous communication
with me, adopted the large wheels, as a necessary consequence of the
speed required. The recommendation coming from such quarters, there can
be no necessity for defending my opinion in its favour; neither have I
now the slightest doubt of its correctness. As it has been supposed that
the manufacturers may have been compelled or induced by me to adopt
certain modes of construction, or certain dimensions, in other parts by
a specification--a practice which has been adopted on some lines--and
that these restrictions may have embarrassed them, I should wish to take
this opportunity to state distinctly that such is not the case. I have
indeed strongly recommended to their consideration the advantages of
having very large and well-formed steam passages, which generally they
have adopted, and with good results; and with this single exception, if
it can be considered one, they have been left unfettered by me (perhaps
too much so) and uninfluenced, except indeed by the prejudices and fears
of those by whom they have been surrounded, which have by no means
diminished the difficulties I have had to contend with.
The principal proportions of these engines being those which have been
recommended by the most able experimentalists and writers, and these
having been adopted by the most experienced makers, it is difficult to
understand who can constitute themselves objectors, or what can be their
objections.
Even if these engines had not been found effective, at least it must be
admitted that the best and most liberal means had been adopted to
procure them; but I am far from asking such an admission. The engines,
I think, have proved to be well adapted to the particular task for which
they were calculated--namely, high speeds--but circumstances prevent
their being beneficially applied to this purpose at present, and they
are, therefore, working under great disadvantages. An engine constructed
expressly for a high velocity cannot, of course, be well adapted to
exert great power at a low speed; neither can it be well adapted for
stopping frequently and regaining its speed. But such was not the
intention when these engines were made, neither will it be the case when
the arrangements on the line are complete; in the meantime, our average
rate of travelling is much greater than it was either on the Grand
Junction or the Birmingham Railway within the same period of the
opening. I have but one serious objection to make to our present
engines, and for this, strange as it may seem, I feel that we are mainly
indebted to those who have been most loud in their complaints--I refer
to the unnecessary weight of the engines. There is nothing in the wide
gauge which involves any considerable increased weight in the engine. An
engine of the same power and capacity for speed, whether for a 4-feet
8-inch rail, or for a 7-feet rail, will have identically the same
boiler, the same fire-box, the same cylinder and piston, and other
working gear, the same side frames, and the same wheels; the axles and
the cross-framing will alone differ, and upon these alone need there be
any increase; but, if these were doubled in weight, the difference upon
the whole engine would be immaterial. But the repeated assertion,
frequently professing to come from experienced authorities, and repeated
until it was supposed to be proved, that the increased gauge must
require increased strength and great power, was not without its indirect
effect upon the manufacturers. Unnecessary dimensions have been given to
many parts, and the weight thereby increased--rather tending, as I
believe, to diminish than to add to the strength of the whole. I thought
then, and I believe now, that it would have been unwise in this case to
have resisted the general opinion, and taken upon myself the
responsibility which belonged to the manufacturers; but I need not now
hesitate to say that a very considerable reduction may be effected, and
that no such unusual precautions are necessary to meet these anticipated
strains and resistances--such being, in fact, imaginary. It cannot
surprise anybody that, under such circumstances, attention was more
occupied in endeavouring to meet these imaginary prejudiced objections,
than in boldly taking advantage of the new circumstances, and that a
piece of machinery constructed under such disadvantages was not likely
to be a fair sample of what might be done. I am happy to say, however,
that the result of the trials that have been made has entirely destroyed
all credit in these alarmists with the manufacturer, and that we may
hope in future to have the benefits of the free exercise of the
intelligence and practical knowledge of engine-manufacturers.
The mode of laying the rails is the next point which I shall consider.
It may appear strange that I should again in this case disclaim having
attempted anything perfectly new; yet regard to truth compels me to do
so. I have recommended, in the case of the Great Western, the principle
of a continuous bearing of timber under the rail, instead of isolated
supports--an old system recently revived, and as such I described it in
my Report of January 1836; the result of many hundred miles laid in this
manner in America, and of some detached portions of railways in England,
was quite sufficient to prove that the system was attended with many
advantages; but since we first adopted it these proofs have been
multiplied--there need now be no apprehension. There are railways in
full work, upon which the experiment has been tried sufficiently to
prove beyond doubt, to those willing to be convinced, that a permanent
way in continuous bearings of wood may be constructed, in which the
motion will be much smoother, the noise less, and consequently--for they
are effects produced by the same cause--the wear and tear of the
machinery much less. Such a plan is certainly best adapted for high
speeds, and this is the system recommended by me and adopted on our
road. There are, no doubt, different modes of construction, and that
which I have adopted as an improvement upon others may, on the contrary,
be attended with disadvantages. For the system I will strenuously
contend.
But I should be sorry to enter with any such determined feeling into a
discussion of the merits of the particular mode of construction. I would
refer to my last Report for the reasons which influenced me, and the
objects I had in view in introducing the piling; that part which had
been made under my own eye answered fully all my expectations. Here the
piles did answer their purpose, and no inconvenience resulted from their
use. The difficulties which we have since encountered, the bad state in
which the line was for a considerable time, and which is only recently
improved, have undoubtedly been aggravated, if not caused, by these
piles; but not, as I believe, from a defect in the principle as applied
in our case, where the line is mostly in cutting, or on the surface, but
from defective execution; for, notwithstanding the determination to
allow sufficient time for this most important operation, yet, to make up
for previous delays and loss of time, it became necessary at last to
force forward the work more rapidly than was at all consistent with due
care in the execution; and during the whole of this period I was most
unfortunately prevented by a serious accident from even seeing the work
almost until the day of opening, when I ought to have personally
superintended the whole. I do not mean that the work was neglected by
those whose duty it was to supply my place--far from it; but in such a
case, a new work cannot be properly directed except under the eye of the
master. Following exactly the plan which had succeeded on the first
piece completed, several serious faults were committed. A much greater
density and firmness of packing is required than was previously
supposed; the mode of packing adopted, and the material selected, in the
first instance, have proved defective elsewhere; and over a great extent
in the line, particularly in the clay cuttings, and where the work was
at last most hurried, it has been badly executed. But many parts have
stood well from the commencement; others are fast improving; and I have
the satisfaction, although a very painful one, of seeing that if, in the
first instance, a foundation of coarse gravel had been everywhere well
rammed in before the timbers had been laid, and the packing formed upon
this, we should, from the outset, have obtained as solid a road as we
have now over a great part of the line. What we have been able to effect
since the opening of the line has necessarily been a slow, expensive,
and laborious operation. We have been compelled to open the ground, and
excavate it to a depth of 18 inches under the longitudinal timbers, and
this without interrupting the traffic: to remove the whole of the
material thus obtained from off the line, and to replace it by coarse
ballast; and not having the means of sufficiently consolidating this
ballast by ramming while the timber is in its place, the packing has to
be repeated once or twice after it has been compressed by the passing of
the trains. This new packing, however, does stand, and in a few weeks I
expect the line will be in a very different state from that in which it
has been, or indeed now is. From what I have described as the result
which can now be, and might have been, obtained from the commencement,
it will be inferred that I am disposed still to defend the system of
piling. I certainly could not abandon it from conviction of its
inefficiency, for I see proofs of the contrary; and I feel that under
similar circumstances I could now prevent the mischief which has
occurred. Upon that portion of the line where the permanent way must
next be formed, piling could not be resorted to, the ground being a
solid hard chalk for many miles. I had intended, however, recommending
the same principle, but in a different form, holding down the
longitudinals by small iron rods driven into the chalk; but the same
objection could not exist, because the chalk cannot yield under the
timbers like clay, or even gravel. But I should wish most anxiously to
avoid anything like an obstinate adherence to a plan, if the object
which I believe essential can be obtained by other means, particularly
when, that plan being my own, I may be somewhat prejudiced in its
favour. I find that the system of piling involves considerable expenses
in the first construction, and requires perhaps too great a perfection
in the whole work, and that if the whole or a part of this cost were
expended in increased scantling of timber and weight of metal, that a
very solid continuous rail would be formed.
For this as a principle, as for the width of gauge, I am prepared to
contend, and to stand or fall by it, believing it to be a most essential
improvement, where high speeds are to be obtained. I strongly urge upon
you not to hesitate upon these two main points, which, combined with
what may be termed the natural advantages of the line, will eventually
secure to you a superiority which, under other circumstances, cannot be
obtained.
As regards the expense of forming the permanent way on this principle, I
am quite prepared to maintain what I have on a former occasion advanced:
that even on the system which we have adopted between London and
Maidenhead, the total cost does not materially exceed that of a
well-constructed line with stone blocks. I did not make in the outset an
exact estimate of the cost of either mode; I was unable to obtain the
cost which has actually been incurred on other lines; but a comparative
estimate was made, and the result of that comparison led me to state
that the one might exceed the other by 500_l._ a mile. The actual cost
of our permanent way appears, by the detailed account which has been
made out, to have been above 9,000_l._, including expenses of
under-draining and forming the surfaces which cannot be included in the
cost given in other cases, because that drainage (although I believe
generally forming part of the plan) is not yet constructed. This sum
includes the sidings at the stations, switches, joints, and other
contingencies, and also the expenses incurred during the first month of
working the line, and which, as I have before stated, consisted in
removing and replacing work which had been improperly executed. These
items will make a considerable reduction; and besides these, larger
reductions may be effected in parts of the work which were new, and,
from the circumstances naturally attending a first attempt, were not so
economically conducted as they might be, or indeed, as they were towards
the close of the works, when the different parts were let by contract.
Taking the prices at which the work was latterly actually executed,
8,000_l._ per mile would be a liberal allowance for our future
proceeding, even adopting the same system; and with a modified system,
such as that suggested of simple longitudinal bearers of large
scantling, and a rail of fifty-four pounds per yard, at the present high
price of iron, the cost, calculated upon our actual past expenditure,
would not exceed 7,400_l._ per mile. This, I am aware, is a larger sum
than that which has usually been assumed as the cost of the permanent
way. I cannot prove that others have cost more, or even so much as this,
as I have nothing but the published accounts to refer to; but this I can
state, and prove if necessary, that rails and blocks, such as are now
being adopted on the Manchester and Liverpool Railway, would upon our
line cost at least as much.
The prime cost of rails and chairs delivered on the line would alone
amount to half the money; and nothing is, perhaps, more certain than
that the experience of other lines within the last two or three years
has proved that this part of the construction of a railway is
unavoidably much more expensive than was ever calculated for at the time
our estimates were made.
I am, gentlemen, your obedient servant,
(Signed) I. K. BRUNEL.
APPENDIX II.
(_See Chapter IX. on the ‘Great Britain’ Steam-Ship, p. 254._)
_Report to the Directors of the Great Western Steam-Ship Company._
October 1840.
GENTLEMEN,--I have now the pleasure to lay before you the result of the
different experiments which I have made, and of the best consideration I
have been enabled to give to the subject of the screw propeller.
The observations which I have to make are naturally divided under two
principal heads, namely: first, the simple question of the applicability
and efficiency of the screw considered merely as a means of propelling a
vessel, compared with the ordinary paddlewheel; and, secondly, the
general advantages or disadvantages attending its use.
The consideration of the comparative efficiency of the screw as a means
of propelling, of course embraces the whole question, not merely of the
effect produced, but also that of the proportionate power absorbed in
producing that effect.
With respect to the mere effect of a screw, the performance of the
‘Archimedes’ has proved, in a satisfactory and undeniable manner, that a
screw acting against the water with a surface even much smaller than
that offered by the paddle-boards of a well-proportioned paddlewheel,
will propel the ship at a very fair speed, but at what expense of power
this effect has been produced is not so evident.
I shall first examine into the principal cause of what amounts
practically to a loss of power, and which is common in a greater or less
degree to all modes of propelling a vessel by exerting a pressure
against the water as against a fixed point.
The resistance, whether to the surface of a screw, or of a paddle-board,
or of the blade of an oar, or any other propelling body, offered by the
fluid against which it acts, is of course not perfect, and there is a
certain amount of yielding, commonly called the slip, of the
paddlewheel; the amount thus slipped causes a considerable waste of
power, inasmuch as the full power of the engine is expended through the
entire space passed over by the paddles or other propelling surface,
while the useful effect produced is only equal to the same power
expended over the space through which the vessel passes: this loss
frequently amounts to one-quarter, and even one-third, of the whole
power employed. To investigate theoretically the amount of slip due to
any given form and quantity of surface, involves much more complicated
calculations than have generally been applied, and would indeed require
data which we hardly possess; but fortunately we have had the means of
making experiments, the results of which enable us to determine the
comparative slip of the paddle and of the screw, with sufficient
accuracy for all practical purposes.
The screw in use on board the ‘Archimedes’ is 5 feet 9 inches diameter,
with a pitch of 8 feet--that is to say, in making one revolution the
thread of the screw advances 8 feet; the area of the screw, considered
as a disc of the same diameter, or the extent of the surface of water
which is acted upon in the direction of the axis of the vessel, is
therefore about 26 feet, without deducting the section of the
shaft-bearing, &c. The midship section of the vessel when I experimented
upon her was, according to Mr. Patterson’s estimate, 122 feet; the ratio
of the resisting surface to the midship section being therefore as 1 to
4·7, which is a small proportion; and the form of the vessel is by no
means peculiarly good as a steamboat. This proportion of propelling
surface to midship section is much smaller--that is, the area of the
screw is much less in proportion to the size of the vessel than is the
area of paddle-boards immersed in steamboats generally.
The average paddle-board immersed and really effective is rather
difficult to estimate, as allowances must be made for the disturbance of
the water, when the wheel is in motion; but this average in the ‘Great
Western’ measured perpendicularly--that is, allowing for the obliquity
of the paddle--cannot be less than 180 to 200 feet, say only 180, while
the midship section averages about 462 feet; the surface of paddle is
therefore about 1/2·56 of the midship section.
I will now give the comparative effects of these different propelling
surfaces in these two cases.
I have made very accurate experiments upon the comparative rate of the
‘Archimedes,’ and of the space passed through by the screw, and was
enabled to determine this ratio with great certainty.
The average of a number of trials gave the following results:
Rate of ship, 50,867 feet per hour, or about 8⅓ knots.
Space passed through by screw due to the number of revolutions, 65,685
feet.
The average rate of vessel being to that of screw therefore as 1 to
1·2913.
In the performances of the ‘Great Western,’ upon an average of 20
voyages the ratio has been as 1 to 1·2997; but, separating from these 20
such voyages as were unusually short or long, and taking only such as,
occupying 14, 15, or 16 days, may be considered as giving a fair average
of the speed of the ship when not adversely affected by the wind or
heavy seas, the average of these 13 voyages give 1 to 1·283; and leaving
out again those of 16 days, and taking only 8 voyages of 14 and 15 days,
the average gives a ratio of 1 to 1·27187.
Of these, 5 voyages of 15 days give 1 to 1·29077,
and 3 " 14 " 1 to 1·23901.
The last three, however, were short passages and homeward, when the
currents and winds have been in favour, and consequently we may safely
say that the ratio must be above 1 to 1·239; and after making every
allowance for the effect of swell and other impediments (the experiments
upon the ‘Archimedes’ being made in smooth water), the average of the 8
(5 of which were homeward voyages with favourable current and wind and
the vessel in good trim), giving a ratio of 1 to 1·27, may be taken as a
fair average.
The comparison between the ‘Archimedes’ and the ‘Great Western’ will
therefore stand thus--
Area of Propelling Difference of Speed of
Surface, the Midship Vessel and Propelling
Section being 1·0. Surface, or amount
of Slip, the ratio
of Vessel being 1·0.
‘Archimedes,’ screw 0·203 0·2913
‘Great Western,’ paddle 0·391 0·2708
Showing an amount of slip in the ‘Great Western’ very nearly equal to
that of the ‘Archimedes,’ while the ratio of the propelling surface to
the midship section in the case of the screw is little more than half
that of the paddle-boards in the ‘Great Western.’
In taking the average of the eight voyages of the ‘Great Western’ with
favourable winds as I have done, I believe I have made full allowance
for the different circumstances of smooth water and sea; but there is
ample room in the above comparison to make even greater allowance for
these circumstances, and still to leave a result which would prove that
with _similar areas_ the screw would meet with at least equal, if not a
greater resistance, and consequently will slip as little or less than
the ordinary paddle-board.
I subjoin a table also, taken from a well-known work on the steam-engine
(Tredgold’s), of the slip of a number of vessels, of which in every case
the surface of paddle immersed is far greater in proportion to the
midship section than that of the screw in the ‘Archimedes.’
_Rate of Paddle, that of Ship being_ 1.
Medea 1·595
Flamer 1·483
Firebrand 1·501
Columbine 1·529
Salamander 1·200[200]
Dee 1·366
Firefly 1·364
Firebrand, as altered 1·295
Phito 1·215
Monarch 1·323
Magnet 1·310
Meteor 1·490
Carron 1·287
Average 1·381
Great Western 1·27
Archimedes 1·29
This list shows that the result in the ‘Great Western,’ with which ship
I have made the comparison, is in itself a favourable one, and that
compared with many others the ‘Archimedes’ would stand much better.
This apparent superiority of the screw over the paddle as regards the
resistance offered to it by the water may at first appear startling, but
there is a great mistake committed in assuming that the action of the
screw is a very oblique action, tending rather to drive the water
laterally with a rotatory motion than to push it steadily backwards.
Having witnessed and carefully observed the degree and the nature of the
disturbance in the water caused by the screw, and comparing this with
the violent displacement of the water by the action of paddle-boards,
even under the most favourable circumstances, I no longer feel
surprised.
The mass of water pushed backwards by the action of the screw appears to
be very large, spreading from the screw probably in the form of an
inverted cone, but there is little or no appearance of any rotatory
motion, and the surface of the water is not put into rapid motion as in
the case of the paddlewheel, which may be observed to impart a
considerable velocity to the water, probably for a small depth only, but
over a very large space.
As regards the oblique action also, a great mistake appears to have been
generally made, and very naturally made, by most persons when first
considering the working of the screw. It is generally assumed that the
inclined plane formed by the thread of the screw strikes the particles
of water at that angle and with the velocity of the revolution of the
screw, but it is forgotten that the screw is moving forward with the
ship, and therefore that the angle at which the water is struck by the
plane is diminished by all that much that the ship with the screw
advances--indeed, it is evident that if the ship advanced the whole
amount of the pitch of the screw, the screw, oblique as it appears, and
rapidly as it revolves, would not strike the water at all, but simply
glide through.
The angle at which any given part of the screw does in fact strike the
water is only equal to the difference between the angle to which that
part of the screw is formed and the angle or direction in which it moves
by the compound motion of the revolution of the screw and of the forward
motion of the ship and screw; and, contrary to one’s hastily imbibed
notions of the action of the screw, this angle at which the plane of the
screw is driven against the particles of water, is in such a screw as
that of the ‘Archimedes’ very nearly equal over the greater portion of
the surface, diminishing to nothing at the centre; and the motion
imparted to the water, although perpendicular to the plane of the screw
in point of direction, is small in extent or velocity, being also nearly
the same over the whole surface of the screw, except close to the
centre, where it is infinitely small.
In the ‘Archimedes’ screw, which appears to the eye so oblique, and the
centre part of which would appear to act flat against the water, only
causing it to revolve, the outer circumference being 18 feet and the
slip 1 foot 8 inches, the angle at which this outer edge acts upon the
water is only one in 11½.
The total amount of motion imparted to the water at right angles to the
plane of the screw by one entire revolution even at the outer edge is
not quite equal to the slip, being only 1·67 foot. The rotatory motion
is still less, the total distance to which any particle of water is
displaced laterally, or at right angles to the axis of the ship, by one
entire revolution of the screw being at the outer edge only 0·69 foot,
and the maximum distance being in any screw only equal to half the slip,
and occurring at that part of the screw where the circumference is equal
to the advance of the ship due to one revolution. This maximum of
lateral motion is 0·9 foot, and takes place at 0·99 foot, or about 1
foot from the centre. In this mode of considering the direction at which
the particles of water are acted upon by the plate of the screw I have
taken no notice of the effect of the friction upon the surface of the
screw, which, causing to be carried with it a film of water, will modify
more or less according to the degree of smoothness of the surface the
effect of the screw upon the water; and towards the centre this
friction, however smooth the surface may be made, will gradually become
equal to, and at last greater than, the propelling effect of that part
of the screw; but this defect applies only to a very small portion of
the whole area of the screw, and the absence of any very violent impulse
to the water in a direction approaching to a right angle with the axis
of the vessel, and which has always been assumed as an unavoidable evil
in the screw, will account for the absence I have observed upon of any
apparent rotatory motion.
I would not pretend, however, to advance these circumstances which I
have observed, or these reasonings, as arguments whereon to found an
opinion of the action of the screw, the facts as proved by the
experiments are what I rely upon; but it is satisfactory to be able to
account for the results by circumstances actually observed, and the
reasons which suggest themselves.
The effect of a propelling surface in the form of a screw, and moving at
a certain velocity, as compared with an equal surface moving at the same
velocity but applied in the shape of paddle-boards, having been
ascertained, it remains to determine the comparative power required to
give motion to that surface.
The difficulty of determining this with any degree of accuracy from any
experiments which we could make on board the ‘Archimedes’ was very
great, but considering such results as I could obtain in conjunction
with experiments which I have since made in our own works, and with the
results upon steamboats recorded by others, and of those of experiments
made by Colonel Beaufoy on the resistance of bodies in water, I think we
may arrive at approximate conclusions sufficiently accurate for our
purpose, and which may safely be relied upon.
In the case of the ‘Archimedes’ the engines were certainly not effective
well-working engines, the proportions of the gearing or wheel-work
between the engine and the screw was bad--such that the engine could not
attain its proper speed--the friction of the gearing (which, whether it
be a source of resistance necessarily attending the use of the screw or
not, I shall consider afterwards) was very great, and the surface of the
screw itself, which I had an opportunity of examining out of water, was
so rough as necessarily to create very much more friction than would be
caused by a tolerably smooth metallic surface. With all these sources of
resistance, and under these unfavourable circumstances, the power
calculated for the effective pressure on the piston and without
deduction for friction or other causes, which, for the sake of
distinction hereafter, I shall call the gross power, was about 145
horses, the speed of the vessel being about 8⅓ knots per hour, as
actually measured by the land, and full 9 knots as measured with great
care by heaving the common log, the midship section being, as before
stated, 122 feet, and the lines of the vessel not so good as those of
fast boats; comparing this with the gross power of the ‘Great Western’
engines when propelling that vessel at the same velocity, with the
advantage of better lines and the other advantages arising from greater
dimensions, there does not appear any such discrepancy as to indicate
any loss of power by the use of the screw in the ‘Archimedes’; on the
contrary, the power expended in the ‘Great Western’ is actually as great
as that in the ‘Archimedes,’ as compared with their relative midship
sections--and if any great allowance is to be made for the circumstances
which I have referred to of larger dimensions and better lines, there
would appear to be actually less power expended in proportion to the
dimensions and form of the ‘Archimedes’ than in the ‘Great Western.’
The results obtained with the ‘Great Western,’ which as regards speed
are similar to those of the ‘Archimedes,’ are necessarily taken from
experiments made when she was rather deep, and the speed thereby reduced
to 7·9 knots; but I have compared these with results reduced by
calculations from experiments at higher speeds, and I find them agree
satisfactorily--indeed, at the draft and consequent immersion of paddles
when in this state, I consider the ‘Great Western’ as very nearly at her
best as regards economy of power and effect produced. I should observe
that the particular experiments from which the following calculations
are deduced were made with the ‘Great Western’ in smooth water in the
Severn. I have added also some calculations deduced from data given by
Tredgold as to the performance of the ‘Ruby,’ a good boat with immense
surface of paddle-board.
The comparison stands thus:
+--------------------------------------+---------+-----------+-----+
| | GREAT | |
| | WESTERN | ARCHIMEDES| RUBY|
+--------------------------------------+---------+-----------+-----+
|ACTUAL DIMENSIONS: | | | |
| Midship section | 520 | 122 | 63 |
| Area of board immersed | 230 | --- | 64 |
| Area of a disc of diameter of screw | --- | 26 | -- |
| | | | |
|RELATIVE DIMENSIONS AND POWER: | | | |
| Area of propelling surface, midship | | | |
| section being = 1 | 0·442 | 0·213 |1·016|
| Gross power expended for one | | | |
| square foot of midship section | 1·023 | 1·026 |0·976|
+--------------------------------------+---------+-----------+-----+-
The speed being the same, viz., 7·9 knots, the power expended is as
nearly as possible the same in the three, and equal to one horse-power
gross to one foot of midship section; while the relative propelling
surface in the ‘Archimedes’ is equal to only half that of the ‘Great
Western,’ and one-fifth that of the ‘Ruby.’ This _gross_ horse-power, it
will be observed, is _about_ equal to one-half a nominal horse-power.
I have made several comparisons with recorded observations made on board
the ‘Great Western’ at different times, and with experiments made in
other vessels, and I find the same result; in estimating the powers used
more particularly in some comparisons with the ‘Great Western,’ I have
taken the mean pressure as ascertained on both sides of the piston,
while in the ‘Archimedes’ I only obtained that on the top of the piston,
which appears generally to be the best, and consequently the estimate is
made unfavourably to the ‘Archimedes.’
Such general results are all that I could obtain from the experiments on
board the ‘Archimedes,’ but since that time I have made some experiments
upon the friction of a plate of metal in water, and have compared these
results with the experiments of Colonel Beaufoy, and the conclusion I
have come to is that the power absorbed by friction in a well-made
screw, apart from all question of the means adopted for working it,
would not be such as to interfere with its beneficial application.
The resistance created by the screw itself arises principally from two
sources--the resistance to the cutting edge and the tail-edge, and the
friction of the surface in contact with the water. The amount of the
first may of course be reduced to an unlimited extent by having a fine
edge, and practically such edge ought to be much finer than that of the
screw of the ‘Archimedes.’
The friction upon the surface will of course materially depend upon the
smoothness of that surface, and in the ‘Archimedes’ it was very rough,
the iron being corroded at many places, with exfoliations and small
holes--the corrosion arising apparently from the galvanic effect
produced by the iron and the ship’s copper.
The great number of revolutions required in the screw as compared with
those of the paddlewheel, leads a person to assume, without much
consideration, that a very high velocity is given to the cutting edges
and to the surface of the screw, and consequently that great friction
must be produced--this velocity is not, however, nearly so great as it
at first appears.
In the present screw of the ‘Archimedes’ the velocity of the extreme
point, following its oblique or spiral course, is only about three times
that of the vessel, while the average velocity of either of these knife
edges or of the surface is not twice that of the vessel.
Now without determining what the actual amount of these resistances may
be, we can at once satisfy ourselves that it cannot be very
considerable, by comparing it (which we have the means of doing) with
the resistance caused by the cutwater and any given portion of the
ship’s bottom. The resistance of a knife-edge will be about as the
square of the velocity, and if we assume the surface friction to
increase in the ratio determined by Colonel Beaufoy--namely, at the
1·75th power, or as the 4th root of the 7th power of the velocity--then
the resistance of the knife-edge will be equal to the resistance of a
similar edge of about five and a-half times the length of the diameter
of the screw moving at the same rate as the vessel, and the surface
friction will be equal to that of a piece of the ship’s bottom about six
and five-eighth times the area of the screw--or, in the case of the
‘Archimedes,’ the additional power absorbed by the friction of the screw
would be about equal to that absorbed by the friction of little more
than twice the space of the dead wood which had been cut out to receive
the screw--while the knife-edges would be about equivalent to three
knife-edges immersed in the water, of the same depth as the ship’s stem.
The actual amount of power absorbed in driving the ‘Archimedes’ screw
was probably about twenty horse-power gross, or from ten to twelve
nominal horse-power; but I have no doubt that a screw of similar
diameter and in good condition would not absorb half that power: and
this amount may be still further, and very much reduced, by increasing
the relative size of the screw to that of the ship, and thereby reducing
the slip, and proportionately reducing the number of revolutions
required.
The great extent to which this is capable of being carried will at once
be seen when I state that if the ship’s progress were made to be 7 feet
instead of 6 feet to each revolution of the screw, which a very slight
increase of diameter and pitch of screw would effect, the power absorbed
in driving the screw would be diminished in the ratio of the
6^{2}^{4} √6^{7} to 7^{2}^{4} √7^{7}--that is, as 6-15/4 to 7-15/4, or about
as 3 to 2.
I must repeat here the observation I have previously made, and remind
you that these calculations are not introduced as _proving_, but merely
as _explaining_, that which appears to me proved by the general results
of the experiments on the ‘Archimedes’--namely, that the effect produced
was, considering all the circumstances, fully proportionate to the power
expended, while the experiments and calculations which I have since made
also satisfy me that these results may be very much improved upon.
As regards the first of the two heads under which I stated that I
proposed to consider the subject, namely, the mere efficiency of the
screw as a propeller, I think but one conclusion can be drawn from the
results of the experiments quoted, and that is, that as compared with
the ordinary paddlewheel of sea-going steamers, the screw is, both as
regards the effect produced, and the proportionate power required to
obtain that effect, an efficient propeller.
I limit the comparison to the ordinary paddlewheels of sea-going
steamers, first, because those are the circumstances which _we_ have
alone to consider; and, secondly, because it is _possible_, by
increasing the diameter and breadth of the paddles, which, for the
attainment of an adequate object is practicable to any extent in a mere
river boat, to render the action of the common paddle all but perfect,
and probably more effective than any other propeller.
In considering the advantages and disadvantages likely to attend the use
of the screw propeller, I will, commencing with the latter, consider
such objections as have been advanced by others, as well as those which
may have occurred to myself.
The only objections, however, which I think worth consideration are:--
First. The necessity of a peculiar form of vessel.
Secondly. The situation of the screw under water, and consequently to a
certain extent unseen and inaccessible, and the liability to injury from
its position from grounding or in other ways.
Thirdly. The probability of its being lifted out of water when the ship
pitched deep.
Fourthly. The difficulty of getting up the required number of
revolutions, and the great defects of the mode employed in the
‘Archimedes,’ and the shaking caused by the machinery.
As regards the form of vessel, undoubtedly a shallow boat, intended for
shallow waters, would be very unfit for the application of the screw,
which would probably require a greater depth of water than the whole
draft of the vessel; but I see no defect or difficulty of this
description in the vessel now under consideration, nor can I anticipate
any in any vessel this Company is likely to be interested in; a clean
run is the most essential condition, and I should suppose no ship was
ever built in which this principle of form was carried to a greater
extent than in our new iron ship. Her present form I believe to be
excellent for the screw, and with a very slight dropping of the keel
towards the stern, which can easily be done now without any expense,
assisted by the different trim, which, as I shall presently show, will
be effected by the use of the screw, the required draft of water will be
attained.
It may, perhaps, be as well to mention here, that the diameter of the
screw, if in the same ratio to the midship section as in the
‘Archimedes,’ would be only 12 feet 3 inches, my friend Captain Claxton
having made a mistake upon this point in calculating it at 16 feet, and
that if increased only to 14 feet 4 inches, the diminution referred to
in a former part of my Report of one-third in the power lost in working
the screw would be effected; considering the speed we wish to attain,
probably 15 feet 6 inches would be a good diameter. Upon the whole I
think the vessel is as well fitted for a screw as she is for paddles,
and much better adapted for either than the ‘Archimedes;’ but if
originally intended for a screw, possibly some trifling modification in
the form and construction, principally of the keel near the stern, might
have been introduced which would have rendered the whole a more perfect
job than she would now be if altered--but the absence of this would in
no way lessen the efficiency of the screw, and I cannot think that any
alteration we might now be obliged to make would exceed in cost the sum
of 200_l_.
Secondly, the inaccessibility of the screw and liability to damage; this
appears to me the objection most plausible, but I cannot say that I
attach much weight to it, particularly in the case of a vessel intended
for long voyages and across the ocean. During the whole passage in deep
water I consider the screw far less exposed to injury than a
paddlewheel, and that the chances of injury are so remote that even if
it were quite inaccessible it would still be altogether safer than
paddles, which are so much exposed; but it is by no means inaccessible,
the screw may be rendered stationary at any time or during any weather,
when it would be barely safe to stop the engines with common paddles,
and when it would be very difficult to do anything to the paddles even
if the engines were stopped, while the whole of the screw, bearings,
&c., may easily be examined and felt from above, and, if necessary, men
sent down with common diving jackets and hoods to replace bearings, or
attach tackle to move the screw, or clear away any obstacle entangled in
it. When in port I still think the chances of injury very remote; an
inspection of our model will satisfy you that from the form and size of
her midship section the vessel cannot lay in any position in which the
screw would touch the ground, while at that time the whole screw may be
very easily examined and replaced without any necessity for going into
dock.
Thirdly, the probability of its being lifted out of water when the ship
pitches deep.
This appears at first to be a very natural and an unavoidable objection,
but the result of observations proves that the motion of vessels, of
steamers at least, is not such as to cause the apprehended difficulty.
Among the observations made on board the ‘Great Western’ steam-ship by
Mr. Berkeley Claxton, under my direction, were measurements of the
angles of rolling and pitching, and from these it was evident that the
vessel never pitches to so great an angle as that to which she rises;
such a result might indeed have been anticipated by considering the form
of the vessel forward and aft, and the circumstance that a steamer is
almost invariably meeting or passing the seas, or, if overtaken by them,
is still going at a good rate, which reduces the relative speed of the
sea; consequently, although the vessel may be frequently thrown up very
violently forward, yet the stern, which has no displacement under water,
settles down quietly and heavily upon the surface; or, considering it in
another way, the variation of displacement at the stern is very rapid,
falling off almost to nothing at a few feet below the water-line, and
spreading out to a great extent at a few feet above, whilst forward the
difference of displacement is comparatively small, the centre of motion,
therefore, is thrown very far aft, and while the bows, which are also
opposed to the first shock, are thrown alternately high out of water or
plunged deeply into it, the stern floats nearly steady, the vessel
resting on its broad counter nearly as the centre of motion: whatever
may be the explanation such is the operation, not only as measured by
instruments, but more particularly as observed since, practically.
In the ‘Great Western’ the whole cutwater and, it is said, a
considerable length of keel, is frequently seen out of water from the
bowsprit, while astern it is very doubtful whether more than half the
stern part was ever seen; marks have been made by my direction on the
rudder to observe this; as yet the 9-foot mark is the lowest seen, and
this occurring rarely, and for very short intervals.
In the ‘Archimedes,’ during a voyage performed in her by Mr. Guppy from
Bristol to Liverpool, and during which they were exposed on more than
one occasion to violent pitching, the screw (which can be watched from
the deck) never was uncovered; and Mr. Smith and others on board the
‘Archimedes,’ whose whole conduct was such as to inspire unusual
confidence in all information obtained from them, assured me that such
was always the case.
In the voyage to Oporto and back, in which I sent Mr. Berkeley Claxton,
he made the same observation; these facts, in conjunction with previous
and subsequent observations on board the ‘Great Western,’ convince me
that nothing is to be feared on this head; but even if the screw were
occasionally to be partly exposed, I know of no evil consequences likely
to ensue, as I shall clearly point out when referring to the
_advantages_ of this propeller over the common paddle.
Fourthly, the difficulty of getting up the required number of
revolutions, and the great defects of the mode employed in the
‘Archimedes.’
Upon this point certainly the ‘Archimedes’ offers but a miserable
example, and the result is almost enough to prejudice the mind of any
person against the whole scheme; the proportions of the gearing, as I
have before stated, are so bad that the engines appear, even to the eye,
to labour ineffectually to get up their speed. The required speed of the
screw is not nearly attained, while the noise and tremor caused by the
machinery is such as to render the vessel uninhabitable, and perfectly
unfit for passengers, I should almost say for a crew. I never attached
much importance to these circumstances, because I felt convinced that
such a mere mechanical difficulty would by some means be overcome, if,
as I confess I did not then at all anticipate, the screw itself should
prove efficient.
The most simple and effectual means of overcoming all objections on
these heads always appeared to me to be by the use of straps instead of
gearing; and all my experience, and I have seen a great deal of the
working of machinery by straps and ropes in the numerous works executed
by my father, led me to the conclusion that there existed no difficulty
whatever in sending the necessary power through a rope or hemp strap,
but I was hardly prepared to find the result so entirely satisfactory as
it has proved to be.
In an experiment made in your works at the yard, I have sent through
two small whale lines, a power equal to about one-thirtieth of that
which would be required in the strap if used in the new ship, and this
without any slip or straining of the rope which would be injurious in
practice, and without any peculiar means of ensuring adhesion to the
drums; so that we have ascertained beyond doubt that sixty such whale
lines upon a drum of only 4 feet 3 inches diameter is adequate to our
wants, but if we suppose seventy lines of superior manufacture to that
used in the experiments with a perfect mode of tightening and working
upon a drum of 6 feet diameter, all of which can easily be had, it will
ensure the perfect and easy working of a mode of obtaining the required
number of revolutions of the screw without noise or tremor. The strap in
question would be only about 3 feet or 3 feet 3 inches broad, easily
replaced piecemeal, and even, if necessary, without stopping the
engines.
All the difficulties enumerated under the fifth head may be considered
as entirely overcome, or rather as ceasing to exist; and so far from the
working of the screw involving difficulties and unavoidable friction,
noise, or tremor, it may be worked with unquestionable and perfect
facility, and as compared even with the best-made paddles in smooth
water, the whole machine will be noiseless.
It is almost unnecessary that I should say that the screw, apart from
the gearing in use on board the ‘Archimedes,’ _cannot_ and _does not_
produce the slightest tremor or noise--it was with some difficulty, and
at least only by attentively listening, that the revolutions of the
screw could be counted, even when disconnected and free from the noise
of the engine or gearing and the vessel being towed, and then only from
some defect in the bearings or the shaft of the screw causing a slight
beat.
In thus answering the objections supposed to have been urged against the
use of the screw, I may probably have appeared to see everything in a
favourable light; unhesitatingly I admit that it is so, and that both
formerly when I was completely sceptical as to the mere efficiency of
the screw as a propeller, and since my doubts on that head have been
removed, I always felt that upon all other points the screw possessed
every superiority that could be desired over a common paddlewheel for a
sea-going vessel.
I shall now proceed to point out the principal advantages peculiar to
the use of the screw; they are--
First. A considerable saving of weight, and that principally top weight.
Secondly. The admitting of a better and simpler form of vessel, having
greater stiffness with the same quantity of material, and offering less
resistance to head wind and seas, and affording more available space
within.
Thirdly. The operation of the screw being unaffected by the trim or the
rolling of the vessel, and allowing of the free use of sails, with the
capability of entirely disconnecting the screw or of varying the
multiplying motion so as to adapt the power of the engine to the
circumstance either of strong adverse winds or scudding.
Fourthly. Perfect regularity of motion and freedom from the possibility
of violent shocks to the engines.
Fifthly. The singularly increased power of steering given to the
vessel--and
Sixthly. The great reduction in the breadth of beam.
I have gone into some detail in calculating the weights of the parts
which are not common to the two systems, and I find that the difference,
or actual diminution in weight in favour of the screw as applied to our
new ship, is upwards of ninety-five tons; but that a much greater weight
even than this is transposed from the top of the ship to the bottom--no
less a mass than one hundred and sixty tons is removed from the level of
the paddle-shaft or from about 10 feet above the water-line, and
replaced by sixty-five tons at about 7 feet below the water-line; not
only is buoyancy, and consequently proportionate space for cargo, gained
to the extent of the difference, but the relief to the labouring of the
vessel in bad weather from the change of position must be immense. If
the reverse were under consideration, if in a vessel fitted for sea,
however stiff in trim or form, it were suggested to remove sixty-five
tons of her ballast, and to place one hundred and sixty tons upon her
deck, and thus navigate her across the Atlantic in all weathers, it
would probably be considered, not merely as highly dangerous, but as
actually impossible. Although such an opinion as that it would be
impracticable we now know would be incorrect, yet the extent of the
beneficial change is much more striking when considered in this way. As
regards the trim of the ship, about one hundred and forty-five tons
would be removed from nearly the centre of flotation, and the balance of
fifty tons added and distributed over the after part, principally quite
aft.
I have not calculated the exact effect of this upon her trim; it would
only bring her down by the stern, and this is a defect which there
seems, as we too well know, never any difficulty in remedying.
Secondly. The simplifying and improving the form of the ship--both as
regards strength and mass exposed to the wind and sea.
The necessity of contracting the midships of a steamer, and making her
completely wall-sided, and forming a sort of recess to receive the
paddles, interferes considerably with the framing of the ship. In a
wooden ship of the size of our new one the whole beam of the ship would
have to be contracted in order to carry the planking through in a direct
line and obtain the requisite fore and aft tie as has been done in the
‘Great Western’; in the new ship the almost infinite resources afforded
by the material used, enabled us to expand the sides and obtain breadth
of beam for cabin room, both before and abaft the paddles, and contract
the sides at the paddles as seen upon the plan; but in order to
strengthen this part, so evidently weak by form, much contrivance and
much material was required. By dispensing with paddles, the best form of
ship is left free to be adopted; perfect lines may be preserved, more
equal strength obtained with increased space, and the whole mass of
paddle-boxes and their accompanying sponsons and deck-houses swept away,
and the resistance of these huge wings to head winds or seas entirely
avoided.
The space gained by avoiding the contraction is calculated by Mr.
Patterson to amount to two hundred tons measurement; this would be
entirely gained, and would not even involve increased dues or tolls, as
it would be added to the engine-room; it would therefore perhaps
counterbalance any loss of room caused by the shaft conveying the
movement from the engine to the screw, but I believe this nominal
increase at one part would not be so great, while in fact the ship would
really be more compact, and, though to a very small extent, a smaller
ship, as the sponsons would be removed.
The third point of advantage named is perhaps the most important. With
paddles, the action is materially affected by the depth of immersion;
when the vessel is deep, and consequently the paddles deep, their action
is impeded, a greater part of the power of the engine is absorbed in
driving the paddle, the speed of the engine is reduced and the effect
diminished; when too light also the paddles do not take sufficient hold
of the water, the amount of slip increases and power is wasted; in
rolling the same effects are produced, and thus at those times when the
greatest effect is required, namely, with deep immersion or in bad
weather to overcome the increased resistance offered to the vessel, the
propelling power is least effective, and Captain Hoskins actually
estimates this loss as occasionally equal to two-thirds the whole power.
The bad effects of one paddle being immersed too deeply, and the other
not sufficiently, also prevents the free use of the sails; and it must
often occur that the impediment thus offered to the working of the
paddles more than counterbalances the good effects of a tolerably fair
wind. With the screw the effect is constant, at least unaffected by the
position or motion of the ship, whether deep or light the screw acts
nearly the same, and as to rolling or heeling over, the screw would work
equally well (as long as it be immersed) if the vessel were on her
beam-ends or bottom upwards.
The screw therefore leaves the ship free to be used as a sailing-vessel
to any extent that other circumstances will admit of, and as long as the
sails draw there can generally be no doubt that the wind is assisting
the ship. The screw may also be thrown in and out of gear at any time
and during any weather, either in case of accident to the engines, or in
the event of her scudding before a gale of wind, when the engine would
be useless; this last, however, I do not consider a probable occurrence,
particularly if another arrangement of which the screw is susceptible be
taken advantage of.
If the motion be conveyed by a strap, as I have recommended, there is no
difficulty in having two or even three drums on the screw-shaft of
different diameters, and thus when the resistance to the ship is very
much increased by strong head winds, deep draught, and other causes, to
use the slow motion and obtain an increased propelling force, or when,
on the contrary, the vessel is running before the wind to use the quick
motion--by which, in both cases, a great increase of speed would be
attained.
This is in fact obtaining at once and by simple means all those
advantages, and to a much fuller extent, which are aimed at in the
reefing-paddles.
Fourthly, great regularity of motion is naturally consequent upon the
screw being unaffected by the rolling of the ship, and upon its being
immersed and not exposed therefore to blows from the sea, and except in
the case of its being lifted out of water, the resistance is perfectly
uniform and perfectly smooth.
An engine could not have a work less capable of causing any jar or shock
as to the effect; even if lifted partially out of water the variation of
resistance would be as easy or soft, to use a mechanical term, as
possible, while the extent of the variation could never approach to that
to which paddles continually expose an engine. A heavy sea or a deep
plunge will occasionally bring the engines nearly to a stand; while at
other moments, if the engineers are to be believed, the paddles are left
free and the engines run away at a fearful speed. I am inclined to think
this description of the effects somewhat exaggerated; but certainly the
screw cannot by possibility be exposed to the same variations as the
paddles--it cannot be stopped by the action of the sea, indeed, being
wholly immersed, the resistance cannot be increased at all, while under
no circumstances can it be relieved to the extent to which paddles are,
which may both on some rare occasions be quite out of the water; and
therefore whether the resistance of the screw is so constant as I
believe it to be, or not, yet as compared with that offered by paddles,
it is certainly all but perfectly constant.
Fifthly, the effect upon the steerage is singular, the mass of water put
into motion by the thrust of the screw is thrown directly upon the
rudder, and the consequence is not only that when the ship is going at
any given rate, the rudder is passing through the water at a greater
rate, and consequently is more sensible, and acts more powerfully upon
the ship; but even when the ship has no way, but the screw is at work,
the rudder is acted upon by water moving perhaps at two or three knots
per hour, and the vessel is still under command--this must be a most
important power to possess in a ship, and must materially diminish many
of the greatest dangers arising from a strong head wind and sea, and at
the same time and under the same circumstances must increase the speed
by improving the steerage.
And lastly, her diminished breadth of beam. Important as this alteration
would be to any vessel, it is peculiarly so as connected with Bristol;
the total breadth, including paddle-boxes, would be at least 78 feet;
with the screw, and taking all the increased beam that might be
convenient, it would be under 50--very nearly 30 feet of difference. One
of the principal objections to her coming up the river would be removed,
and the dock gates might easily be made to receive her.[201]
There are many other points upon which comparisons may be drawn, but I
am not aware that any very important differences exist.
As regards first cost I believe there would be little difference--if
any, it would be in favour of the screw; as a reduction of ninety-five
tons of iron can hardly fail to cause some saving, although some portion
of the substituted machinery may be more costly per ton.
As regards wear and tear I can have no doubt that some considerable
saving would be effected; the paddles are a constant source of trouble
and expense, and seem never to be capable of being kept in good repair;
indeed, they are huge and comparatively light frameworks subjected to
extraordinary and constantly repeated shocks, each arm receiving direct
about 260,000 very sharp blows per voyage, independently of the more
violent shocks from heavy seas, while the screw can be subjected to no
such constant source of mischief.
From all that I have said it must be evident to you, gentlemen, that my
opinion is strong and decided in favour of the advantage of employing
the screw in the new ship; it certainly is so. I am fully aware of the
responsibility I take upon myself by giving this advice, I am also fully
sensible of the large amount we have at stake, and I have not forgotten
the nature and tone of the observations which have on more occasions
than one been so freely made by individuals upon the course we have
hitherto pursued; although, and I have pleasure in referring to the
fact, this course has in every instance where results have been obtained
proved successful; but my conviction of the wisdom, I may almost say the
necessity, of our adopting the improvement I now recommend is too
strong, and I feel it is too well founded, for me to hesitate or to
shrink from the responsibility.
I think I have hardly advanced an opinion which I have not supported,
and in most cases preceded, by a statement of facts, leaving no doubt as
to the correctness and safety of relying on these opinions; still it
would be too much to hope that my mode of laying before you these facts
which I have collected and the opinions I have formed could produce as
strong a conviction in your minds as the consideration of them has in my
own; but if you bear in mind that the actual results of the fair and
full trial of the ‘Archimedes’ for several months has completely
established the fact of the efficiency of the screw as a propeller; that
the experiments I have made, as well as the general and apparent results
of her working, have equally satisfactorily explained the fact of the
power required being no greater in proportion to the effect produced
than in the ‘Great Western’ steam-ship, and many other good steamboats;
and that these results are satisfactorily explained by theory, you
cannot fail to draw the same conclusion that I have done as to the
general question of at least the equal efficiency of the screw.
As to the comparisons I have drawn between the general and what I may
call the indirect advantages of the one mode of propelling over the
other, they seem to me so evident that I am disposed to apologise to you
for having occupied your time in pointing them out, and we have the
satisfaction of knowing that they are now very generally admitted,
particularly by practical men.
In conclusion, I must observe that much more detailed information and
recorded results than appear on the face of this Report have been
required to enable me to form correct comparisons, and to reduce to
calculation and to actual figures and amounts many results observed; and
that it would have been impossible for me to have given you such clear
and positive facts on many most important points without the very
detailed observations made and recorded by Mr. Berkeley Claxton in the
several voyages of the ‘Great Western,’ and also in one on board the
‘Archimedes.’
The information obtained from these logs has been, and may still be, of
the greatest importance to us in our future working, and I have much
pleasure in adding that the manner in which my directions were carried
out was highly creditable to Mr. Berkeley Claxton, who, I think, has
conferred a great benefit on the Company by his labours. I have to
express also my thanks to my friends Captain Claxton and Mr. Guppy for
their assistance in the various experiments which have been made, and in
working out the results.
I am, Gentlemen,
Yours very faithfully,
(Signed) I. K. BRUNEL.
INDEX
‘Adelaide’ steam-ship, built under Mr. Brunel’s directions, 290
Admiralty, Mr. Brunel’s connection with the, respecting the screw propeller, 283.
Communication with the, on floating gun-carriage, 459
Airy, G. B., Astronomer Royal, member of the Gauge Commission, 117.
Correspondence with Mr. Brunel on astronomical observations for the ‘Great Eastern,’ 321
Angarrack, viaduct at, 189
‘Archimedes’ steamer, the screw propeller used in the, 253.
Experiments made in the, 254
Armstrong, Sir W. G.
His hydraulic machinery at Paddington station, 85 _note_.^{1}
Engaged with Mr. Brunel on gunnery investigations, 452.
Letter to, 454, 461
Atlantic cable expeditions of the ‘Great Eastern,’ 412.
Loss of the first cable, 412.
A second one laid, and the first recovered, 413.
The French cable of 1869, 413
Atmospheric system of propulsion on railways, 131.
Description of this method of traction, 134.
History of its introduction prior to 1844, 136.
Mr. Brunel’s views respecting it, 137.
His report recommending its adoption on the South Devon Railway, 138.
Grounds of his recommendation, 142.
Select Committee on, 144.
Working of the system, 153.
Imperfections of engines, 154, and longitudinal valve, 157.
Mr. Brunel’s report on the failure of the Atmospheric apparatus, 159.
Abandonment of the system, 164
Australian Mail Company, Mr. Brunel appointed engineer of the, 290
Barlow, Professor P., member of the Gauge Commission, 117
Barlow, W. H., 57
Bath, station at, 84
Bath, bridges at, 175, 179
Bathford, bridge at, 175
Beamish, Richard, his account of Sir Isambard Brunel’s block machinery at Portsmouth, quoted, 3.
Joins the Thames Tunnel works, 21
Bennett, Joseph, Mr. Brunel’s secretary, 92
Berks and Hants Railway, 88
Birmingham and Oxford Junction Railway, 90
Birmingham, Great Western extension to, 124
Birth of Mr. Brunel, 1
Blake, H. W., consulted by Mr. Brunel on the ‘Great Eastern,’ 297
Block machinery at Portsmouth, Sir Isambard Brunel’s, 2
Bourbon, Ile de, Sir Isambard Brunel’s suspension bridges for the, 5.
Description of them, 40
Bourne viaduct, 181
Box Tunnel, 70 _note_^{1}, 72, 81.
Criticism as to its safety, 81.
Letter from Mr. Brunel on the, 81
Bremner, A., 263, 280
Brentford, dock at, 440
Brentford, extension of the Great Western Railway to, 86
Brereton, Robert Pearson, chief of Mr. Brunel’s engineering staff, 92, 210, 215 _note_^{1}, 217 _note_^{1}, 223, 225, 437, 438 _note_^{1}
Brickwork, use of, 59.
Bridges in, 172
Bridges, suspension, Sir Isambard Brunel’s: in the Ile de Bourbon, 5, 40; designs for the Serpentine, and for the Thames at Kingston, 5.
Mr. Brunel’s: at Clifton, 46; Charing Cross, 59
Bridges, railway, 171.
1. Brickwork and masonry bridges, 172.
Flying bridges, 176.
Skew bridges, 177.
Letter from Mr. Brunel on bridge construction, 178.
2. Timber bridges and viaducts, 179.
3. Cast-iron bridges, 190.
4. Wrought-iron bridges, 192.
Girder bridges, 193.
Opening bridges, 195.
Trussed bridges, 199.
Extracts from letters on bridges of large span, 212 _note_^{1}.
Experiments on matters connected with bridge construction, 227
Bristol, Mr. Brunel’s early connection with, 58, 64.
Station at, 84.
Bridges at, 175, 195.
Floating Harbour, 422.
Proposed improvement of the port, 426.
New lock at, 427
Bristol and Exeter Railway, 86
Bristol and Gloucester Railway, 90
Bristol and South Wales Union Railway, 90
Briton Ferry Docks, 437
Broad Gauge. _See_ Gauge
Brunel, Sir Marc Isambard, birth of, 2.
Arrives in England, 2.
Marries Miss Sophia Kingdom, 2.
Designs the Block machinery at Portsmouth, 2.
Veneering machinery, 5.
Shoe machinery, 5.
Designs suspension bridges for the Ile de Bourbon, 5, 40.
Experiments on carbonic acid gas, 5, 42.
Proposes the Thames Tunnel, 5.
Extracts from his Journal relating to the Rotherhithe shaft, 10.
Extracts from his Journal relating to the works at the Thames Tunnel up to January 1828, 16.
His death, 39.
Hoop iron introduced by, in brickwork, 177.
Designed a large timber bridge to cross the Neva, 211 _note_^{2}
Bullo Pill opening bridge, 197
Caermarthen, opening bridge at, 198
Carbonic acid gas, experiments on, by Sir Isambard Brunel and Mr. Brunel, 5, 42
Cast-iron bridges, 190.
Mr. Brunel’s views as to the use of cast iron in bridge construction, 190, 192
Cheltenham and Great Western Union Railway, 88
Chepstow bridge, 203.
Mode of forming piers, 203.
Description of superstructure, 206.
Floating and erection, 209
Clarke, Seymour, 117
Claxton, Captain, 57.
Assists Mr. Brunel at the floating of the Chepstow bridge, 210.
And the Saltash bridge, 222.
Appointed Managing Director of the Great Western Steam-Ship Company, 234, 242, 247.
Letter to, from Mr. Brunel, on the ‘Great Britain,’ 264.
Goes to Dundrum to carry out Mr. Brunel’s plans for the protection of the ‘Great Britain,’ 272.
Letter to, from Mr. Brunel, on the breakwater, 272.
Report of, on breakwater, 274.
Superintends floating of the ‘Great Britain,’ 280.
Consulted by Mr. Brunel on the ‘Great Eastern,’ 291, 297.
Floating Harbour, Bristol, 424
Clifton Suspension Bridge, origin of the, 47.
Mr. Brunel’s designs, 47.
Rejected by Mr. Telford, 51.
Mr. Telford’s own design, 52.
Second competition, 52.
Mr. Brunel successful, and appointed engineer, 53.
The site described, 54.
Description of the design, 55.
Architectural features, 56.
Commencement of the work, 56.
Completed, 57
Coles, Captain Cowper, 461
Construction of works, letter on, 178
Continuous girders, 208
Cork and Youghal Railway, 91
Cornwall Railway, 87.
Viaducts on, 185
Crystal Palace at Sydenham, water-towers of the, 448
Cylinders, of Chepstow bridge, method of sinking the, 204.
The great cylinder of the Royal Albert Bridge, 214
Dalkey Railway, Atmospheric System on, 131
Dartmouth and Torbay Railway, 87
Death of Mr. Brunel, 520
Dock and pier works:
Monkwearmouth, 418;
Bristol, 422;
Plymouth, 433;
Briton Ferry, 437;
Brentford, 440;
Neyland, 443
Draught, Mr. Brunel’s paper on, 101 _note_^{1}
Dublin, railway to Wicklow from, 91
Dundrum Bay, stranding of the ‘Great Britain’ in, 263
Early life of Mr. Brunel.
He goes to school at Chelsea, 4; at Brighton, 4; at Paris, 5.
Employed in his father’s office, 5.
Engaged at the Thames Tunnel, 6.
References by Sir I. Brunel to his exertions, 17, 19, 21, 22, 25, 33.
Appointed resident engineer, 25 _note_^{1}.
First irruption of the river, 29.
Second irruption, 35.
Accident, 36.
Visit to Plymouth, 46
Eastern Bengal Railway, 91, 195, 517
Eastern Counties Railway, gauge adopted on the, 105
Eastern Steam Navigation Company, formation of the, 291.
_See_ ‘Great Eastern’
Egypt, visit to, 517
Electric telegraph, application of the, in connection with railways, 155
Engineer, Mr. Brunel’s view of the position of, 475.
Of joint-engineer, 476.
Of consulting engineer, 477.
Of the position of the engineer in relation to the contractors, 477.
To the Directors, 478.
Remarks on interference of Directors with assistant engineers, 481.
On State control over engineering works, 486
Experiments:
Strength of timber, 182, 227.
Cast-iron girders, 190, 191.
Wrought-iron girder, 193.
Riveting, 194, 228.
Continuous beams, 209, 229.
Bridge construction, 227.
Ropes and chains, 228.
Friction, 348, 368, 385
Faraday, M., his experiments on the liquefaction of gases, 42.
Consulted by Mr. Brunel on the Kyanising process, 189
Field, Cyrus, 411, 414
Field, J., consulted by Mr. Brunel on the ‘Great Eastern,’ 297
Floating gun-carriage, 454
Floating harbour at Bristol, 422
Floating pier, proposed at Portishead, 426.
In Mill Bay, 436
Florence and Pistoja Railway, 91
Flying bridges, 176
Ford, Captain Robert, consulted by Mr. Brunel on the ‘Great Eastern,’ 297
Friction, experiments and observations on, 348, 368, 385
Froude, W., letter to, describing floating of the ‘Great Eastern,’ 389
Gathampton, bridge at, 174
Genoa, Novi, and Alessandria Railway, 91
Gauge of railways, difference between the broad and narrow, 99.
Origin of the ordinary gauge, 99.
Adoption of the broad gauge on the Great Western Railway, 101, 106.
Reasons for its adoption, 102.
Attacks on, 106.
Reports of Mr. Wood and Mr. Hawkshaw on, 107.
Report by Mr. Brunel on, 107.
Northern extension, 116.
Inconveniences of a break of gauge, 116.
Royal Commission on the gauge question, 117.
Report of the Commissioners, 117.
‘Observations on the Report,’ 119.
Report of the Board of Trade, 122.
Act for regulating gauge, 122.
The mixed gauge, 124.
Summary of the advantages of the broad gauge, 127.
Partial abandonment of the broad gauge, 127, 129.
Report on the broad gauge, 525
Gilbert, Davies, appointed referee in the second competition for the Clifton Suspension Bridge, 52.
Recommends Mr. Brunel’s design, 53
Girder bridges, 193
Glennie, W., 215 _note_^{1}
Gloucester, opening bridges near, 196
Gloucester and Dean Forest Railway, 88
Gooch, Sir Daniel, 117, 119.
Experiments by, 125
Gravatt, William, an assistant engineer at the Thames Tunnel, 26
‘Great Britain’ steam-ship, commencement of the, 247.
Report on the engines, 249.
Adoption of the screw propeller, 254.
Principal features of her design, 255.
Arrives in the Thames, 261.
Her voyages, 262.
Stranded in Dundrum Bay, 263.
Letter from Mr. Brunel on the subject, 264.
His reports to the Directors, 267, 273.
Construction of breakwater, 274.
Floating of the ship, 280.
Her subsequent history, 282.
Dimensions of ship and engines, 282
‘Great Eastern’ steam-ship, origin of the project, 291.
Memorandum by Mr. Brunel to the Directors of the Eastern Steam Navigation Company, 292.
He is appointed engineer, 293.
Letter on the form and dimensions of the ship, 294.
Report on mode of proceeding, 296.
On enquiries relating to the draught and form of the vessel, 297.
On the dimensions, 299.
Tenders invited, 300.
Report on tenders, 301.
Commencement of the work, 304.
Extracts from Mr. Brunel’s memoranda, 304, 310.
Letters on his position as engineer, 311.
Report describing the ship, 315.
Letter to the Astronomer Royal, 321.
The observers’ department in the ship, 322.
Captain Harrison appointed to the command, 323.
Memorandum on the management of the ship, 324.
Letter on the duties of chief engineer, 335.
Suspension and resumption of the works, 339.
Reasons for launching the ship broadside to the river, 340.
Adoption of iron sliding-surfaces, 343.
The ways and cradles, 345.
Motive power, 348.
Checking gear, 351.
River tackle, 352.
Letter to Captain Harrison on the river tackle, 354.
Letter to the Directors respecting the operation of launching, 355.
Memorandum of arrangements and intended mode of proceeding, 356.
Particular instructions, 358.
Final preparations, 359.
Commencement of the launch, 360.
Accident at one of the drums, 361.
Failure of the first attempt, 362.
Second attempt, 364.
Report on operations, 366.
Progress of the launch, 368.
Suspension of operations, 376.
Report and memorandum, 377.
Re-commencement, 379.
Floating of the ship, 382.
Experiments and observations on friction, 385.
Letter to Mr. W. Froude, describing the floating, 389.
Formation of the Great Ship Company, 393.
Progress of the works to Mr. Brunel’s last illness, 393.
Completion of the ship, 393.
Voyage to Weymouth, 393.
Explosion of water-heater, 393.
Storm at Holyhead, 395.
Description of the ship, 396.
Her first voyages to New York, 403.
To Quebec, with troops, 404.
Accident to rudder, and loss of paddlewheels, 405.
Voyages in 1862, 407.
Accident off Montauk Point, 407.
Formation of Great Eastern Steam-Ship Company, 409.
Remarks on performance of ship, 409.
Employed in laying Atlantic cables, 412.
The Indian cable, 414.
Dimensions of ship and engines, 416
Great Exhibition of 1851, Mr. Brunel’s opinion respecting prizes to exhibitors, 445.
His part in the work of the Building Committee, 446.
Supports Sir Joseph Paxton’s design, 447
Great Western Hotel, 86
Great Western Railway, origin of the, 63.
Mr. Brunel appointed engineer, 64.
Survey of the country, 65.
Bill for a line from London to Reading, and Bath to Bristol, read a second time, and referred to a committee, 66.
Opposition to the Bill, 67.
Plan of entering London, 68.
Mr. Brunel’s cross-examination, 69.
The Bill passed by the Commons, but thrown out in the Lords, 70.
A Bill for the whole line introduced, read a second time, and committed, 71.
Evidence taken before the Commons’ Committee, 72.
Evidence before the Lords’ Committee, 73.
The Bill receives the Royal Assent, 74.
Construction of the line, 80.
Opening from London to Bristol, 80.
Levels and inclines, 80, 104.
The Box Tunnel, 81.
The Bath and Bristol stations, 84.
Paddington station, 84.
Branches and extensions of the railway, 86, 88, 90.
Adoption of the broad gauge, 106.
The permanent way, 108, 111.
Meeting of shareholders on broad gauge, 111.
Extension of the Great Western system, 116
‘Great Western’ steam-ship, formation of the company, 233.
Details of the construction of the vessel, 234 _note_^{2}.
Report on the selection of the builders of the engines, 235.
Controversy with Dr. Lardner, 237.
Launch of the vessel, and voyage to London, 241.
Return to Bristol, 242.
Fire on board, and accident to Mr. Brunel, 242.
First voyage to New York, 243.
Subsequent history, 244.
Dimensions of ship and engines, 245
Gunnery experiments, 452
Guppy, T. R., 148, 233, 234, 247, 253, 254.
Letter to, on iron-ship building, 259
Hammond, J. W., 65, 92
Hanwell, bridge at, destroyed by fire, 190
Hanwell viaduct, 172
Harrison, Captain, 223.
Appointed commander of the ‘Great Eastern,’ 323.
Letter to, on the river tackle, 354.
At the launch, 362, 370, 382, 392
Haverfordwest, opening bridge at, 198
Hawkshaw, J., 57.
Report on broad gauge and permanent way, 107
Henley branch of the Great Western Railway, 86
Hungerford Suspension Bridge, 57, 59
India, railway works in, 91
Indian Cable expedition of the ‘Great Eastern,’ 414
Institution of Civil Engineers, 516 _note_^{2}, 521
Inventors, communications with, 485
Ireland, railway works in, 90
Italy, Mr. Brunel’s railway works in, 91, 510
Ivybridge viaduct, 182
Kennet, bridge over the river, 175
Kidwelly, opening bridge at, 198
Kyanising process, 189, 421
Landore, viaduct at, 183
Lane, Michael, 29
Lardner, Dr., 114 _note_^{1}.
Opinions respecting ocean steam navigation, 237
Llansamlet, flying arches near, 176
Llynvi Valley Railway, 89
Locke, Joseph, 62, 74.
His address on the death of Mr. Brunel, 521
Locomotive power, comparison of, with stationary power, 142, 166
Loughor, opening bridge at, 197
Maidenhead bridge, 96, 173
Masonry, bridges in, 172
Maudslay and Field, 15, 148, 236, 284
Milford Haven, 88, 443
Monkwearmouth, docks at, 417, 418
Moulsford, bridge at, 174
Nasmyth, James, his steam hammer designed, 252 _note_^{1}.
Letter to, on gunnery experiments, 452
Neath, improvement of river, 438 _note_^{1}
Newport viaduct, 185, 199
Neyland, pier at, 443
Ocean steam navigation, Mr. Brunel’s connection with, 231, 313
Opening bridges, 195
Oxford, Mr. Brunel created a Doctor in Civil Law at, 516
Oxford and Rugby extension of the Great Western Railway, 90, 116
Oxford branch of the Great Western Railway, 86
Oxford, Worcester, and Wolverhampton Railway, 90, 116
Paddington station, 84
Paris Exhibition of 1855, letter on decorations conferred at, 489
Parkes, Dr., medical superintendent of Renkioi Hospital, 468.
Report of, on hospital buildings, 468
Patent laws, Mr. Brunel’s opinions on the, 212 _note_,^{1} 450, 451, 454, 485, 489, 497
Patterson, W., 234, 247, 263
Paxton, Sir Joseph, his design for the Great Exhibition building, 447
Permanent way on the Great Western Railway, 108, 535
Plymouth Great Western Docks, 433
Polygonal rifle, 449
Portishead, proposed pier at, 426
Prince Consort, H.R.H. the, opens the Royal Albert Bridge, 226.
Present at floating of the ‘Great Britain,’ 259
Private life of Mr. Brunel, 499.
Early reminiscences, 500.
Removal to Duke Street, and marriage, 505.
His taste in art, 506.
First journey to Italy, 508.
Half-sovereign accident, 511.
Purchase of property in Devonshire, 514.
Life at Watcombe, 515.
Failing health, 516.
Journeys to Switzerland and Egypt, 516.
Letter from Philæ, 517.
His last illness, 520
Quaker’s Yard, viaduct at, 89
Railways, sketch of, in England prior to 1833, 61.
Extent of Mr. Brunel’s, 79.
Great Western, 80.
Branches to Oxford, 86.
Windsor, 86.
Wycombe, 86.
Uxbridge, 86.
Henley, 86.
Brentford, 86.
Bristol and Exeter Railway, 86.
South Devon, 87.
South Devon and Tavistock, 87.
Cornwall, 87.
Branch lines now incorporated with Great Western Railway:
Berks and Hants, 88.
Wilts and Somerset, 88.
Cheltenham and Great Western Union, 88.
Gloucester and Dean Forest, 88.
The South Wales, 88.
The Taff Vale, 89.
The Vale of Neath, 89.
The Llynvi Valley, 89.
The South Wales Mineral, 89.
Bristol and South Wales Union, 90.
Bristol and Gloucester, 90.
The Oxford and Rugby, 90.
Birmingham and Oxford Junction, 90.
Oxford, Worcester, and Wolverhampton, 90.
Ireland, 90.
Italy, 91.
India (Eastern Bengal), 91
Railway Structures, letter on the Royal Commission on the Application of Iron to, 192, 486
‘Rattler’ steam-ship, trials with the, 287
Rendel, J. M., 211, 433
Renkioi, hospital buildings at, 461.
Description of the buildings, 463.
Dr. Parkes’s report on the formation and general management of the hospital, 468
Rennie, G. and J., 148
Richards, Westley, letters to, on polygonal rifle, 450
Riveting, experiments on, 194, 228
Ropes and chains, experiments on, 228
Rotherhithe shaft of the Thames Tunnel, construction of the, 9
Royal Albert Bridge at Saltash, 211.
Plans for crossing the river Tamar at Saltash, 211.
Trial cylinder for centre pier, 213.
Report on making bridge for a single line, 214.
Mode of construction of centre pier, 214.
Description of superstructure, 218.
Floating of first truss, 221.
Lifting of first truss, 224.
Floating and lifting of second truss, 225.
Opening by H.R.H. the Prince Consort, 226
Royal Society, 516 _note_^{1}
Russell, J. Scott, builds the ‘Victoria’ and ‘Adelaide,’ 290.
Assists Mr. Brunel in maturing designs of the ‘Great Eastern,’ 291, 292, 297.
Letter to, on the form and dimensions of the ship, 294.
Tender accepted for hull and paddle-engines, 301
St. Mary’s viaduct, 181
St. Pinnock viaduct, 186
Saltash bridge. _See_ Royal Albert Bridge
Samuda, J., 131, 134, 148, 160
Saunders, C. A., 92, 117, 119
Screw propeller, the, adopted for the ‘Great Britain,’ 254.
Communications on, with the Board of Admiralty, 283.
Trials with the ‘Polyphemus,’ 284.
With the ‘Rattler,’ 287.
Report recommending adoption of, 539
Shield, Thames Tunnel, the, 11, 12
‘Sirius’ steam-ship, 241
Skew bridges, 177
Smith, F. P., the screw propeller, 253, 287.
Consulted by Mr. Brunel on the ‘Great Eastern,’ 297, 298
Smith, Sir F., member of the Gauge Commission, 117
Smyth, C. Piazzi, Astronomer Royal for Scotland, correspondence with Mr. Brunel on astronomical instruments for the ‘Great Eastern,’ 322
Sonning Cutting brickwork bridge, 175.
Timber bridge, 179
South Devon and Tavistock Railway, 87.
Viaducts, 188
South Devon Railway, 87.
Course of the line, 132.
Atmospheric System adopted on the, 138.
Viaducts, 182
South Wales Mineral Railway, 89
South Wales Railway, 88.
Viaducts, 183, 194
Standard drawings, 172 _note_^{2}
Stationary and locomotive power, comparison of, 142, 166
Statue of Mr. Brunel, 520 _note_^{1}
Stephenson, George, 61, 62, 70, 74, 99
Stephenson, Robert, 62, 106, 107, 134
Atmospheric System, 136, 137 _note_^{1}, 138, 144.
Conway and Britannia bridges, 221, 223.
Launch of the ‘Great Eastern,’ 375, 376, 377, 378, 384 _note_^{1}, 485, 516, 517, 521
Stonehouse viaduct, 181
Taff Vale Railway, 89, 104 _note_^{1}
Tamar, plans for crossing the river, 5 _note_^{2}, 46, 211
Telford, T., appointed referee to decide upon the plans for the Clifton Suspension Bridge, 51.
Rejects Mr. Brunel’s plan, 51.
Designs one himself, 52.
His plan described, 52
Thames Tunnel, project of, first occupies Sir Isambard Brunel’s attention, 5.
Plans suggested for the construction of a tunnel, 6.
Borings, 7.
Remarks on borings, 8 _note_^{1}.
Commencement of the work, 9.
Construction of the Rotherhithe shaft, 9.
Description of the shield, 12.
Journals of Sir I. Brunel of the progress of the work, 10, 11, 16.
Mr. Brunel appointed resident engineer of, 25 _note_^{1}.
First irruption of the river, 29.
Second irruption, 35.
Works suspended, 37.
Resumed, 38.
The Wapping shaft, 38.
Completed and opened, 39.
Its subsequent history, 39 _note_^{1}
Thompson, Dr. Seth.
Letter on the half-sovereign accident, 511
Timber bridges and viaducts, 179
Timber, experiments on strength of, 182, 227
Torquay branch of the South Devon Railway, 87
Trussed bridges, 199
Uxbridge branch of the Great Western Railway, 86
Vale of Neath Railway, 89.
Viaducts, 171
Vick, Alderman William, his bequest for a bridge at Clifton, 47
‘Victoria’ steam-ship, built under Mr. Brunel’s direction, 290
Vignoles, C., 74
Walker, J., 107
Walkham viaduct, 189
Wapping shaft of the Thames Tunnel, construction of the, 38
Watcombe, Mr. Brunel’s life at, 514
Watt, James & Co., 148.
Tender accepted for screw engines of the ‘Great Eastern,’ 301
West Cornwall Railway, 87.
Viaducts, 189
Westminster Abbey, memorial window in, 520 _note_^{1}
Wilts and Somerset Railway, 88
Windsor branch of the Great Western Railway, 86
Windsor bridge, 200.
Description of superstructure, 200.
Mode of forming piers, 201
Wire gun, 453
Witness, Mr. Brunel’s reputation as a, 69, 93, 505
Wood, Nicholas, 101.
Report on broad gauge and permanent way, 107
Wrought-iron bridges, 192
Wrought-iron girder, experiments on, 193
Wyatt, Sir M. D., 84
Wycombe extension of the Great Western Railway, 86
LONDON: PRINTED BY
SPOTTISWOODE AND CO., NEW-STREET SQUARE
AND PARLIAMENT STREET
* * * * *
Typographical errors corrected by the etext transcriber:
known method of makng=> known method of making {pg 45}
consits merely of=> consists merely of {pg 109}
every calcluation=> every calculation {pg 527}
* * * * *
FOOTNOTES:
[1] To avoid confusion, Sir Isambard Brunel has been called throughout
by that designation, the one by which he is generally known: he was
knighted on March 24, 1841.
His Life has been written by Mr. Richard Beamish, F.R.S. (London, 1862.)
[2] Lady Brunel survived her husband five years. Of their children,
three lived to maturity, one son, Isambard Kingdom, and two daughters,
Sophia, wife of the late Sir Benjamin Hawes, K.C.B., Under Secretary of
State for War, and Emma, wife of the Rev. George Harrison, Rector of
Sutcombe.
[3] He was sent to Paris to recover his knowledge of French, which had
got rather rusty at school, and also to study mathematics. He retained
through life a great admiration of the method of teaching this subject
which was adopted in France.
In addition to the time spent in the study of mathematics and languages,
Mr. Brunel occupied himself on his holidays in examining the various
engineering works going on in Paris, and he used to send his father
drawings and descriptions of them.
[4] Sir Isambard was also consulted upon a proposed suspension bridge
over the Tamar at Saltash, where Mr. Brunel subsequently built the Royal
Albert Bridge.
[5] This history has been written by Mr. Beamish in his _Life of Sir
Isambard Brunel_, pp. 202-304, and also, up to the year 1828, in the
very valuable work by Mr. Henry Law, C.E., entitled ‘A Memoir of the
several Operations, and the Construction, of the Thames Tunnel,’ and
published by the late Mr. Weale in his _Quarterly Papers on
Engineering_.
[6] For an account of these earlier attempts see Law, pp. 3-7.
[7] This expectation does not seem to have been realised, as there was
never any considerable traffic through the Thames Tunnel. Perhaps,
however, it would have been otherwise had the large descents for
carriages and horses been constructed.
[8] The results obtained by these borings were no doubt fallacious, but
not to the extent which has sometimes been imagined. At a meeting of the
Institution of Civil Engineers, in November 1849, Dean Buckland called
attention to ‘the evils arising from the ignorance of the engineers who
reported to Sir Isambard Brunel, previous to the commencement of the
Thames Tunnel, that the whole of the bottom of the river at that spot
was London clay.’ Whereupon Mr. Brunel rose and said, that he ‘agreed
that knowledge of every kind was most desirable, and that it would be
well if engineers were generally much better informed on many subjects
which would be useful, and more particularly on matters connected with
geology; at the same time he could not admit that they were deficient in
that knowledge of the surface of the earth which was necessary for the
purpose of guiding them in their work. It might be true that many
members of the profession were, like himself, not perfectly well
acquainted with the minute geological characteristics of the soils they
had to deal with, but he thought the education and the practical
experience of the profession generally rendered them well acquainted
with those features and characteristics which were necessary for their
guidance in the design or execution of work. He must also say a few
words in defence of those persons (now nearly all dead) who made the
borings in the Thames, and were stated to have made so fallacious a
report previous to the commencement of the Tunnel. Now, although that
statement had by constant repetition become a sort of historical fact,
it was really only one of those popular fallacies which obtained too
ready credence in the world. The position of the Tunnel was not
determined by any report, or by the result of any borings, but with a
view to establishing a communication between particular localities for
encouraging the traffic which was anticipated from the facility of
access to the docks, and for other local reasons, such as the general
direction of the roads and streets on both shores. After the position
was settled, and not until then, borings were made to ascertain what
soils might be expected in that part of the river. It must be remembered
that these borings were made full twenty-five years ago, when boring in
the bed of a river through a depth of water of nearly thirty feet was
not an ordinary occurrence. The tool then generally employed was the
worm, and tubes were not even used in such cases. The borings showed the
existence in that spot of something which, in the ordinary acceptation
of the term, might have been inadvertently called London clay, but he
had no recollection of its geological designation having ever been
thought of. It was reported and shown to be a very fair clay for working
in.... The errors which were made in giving the results of the borings
did not, in fact, arise from ignorance, but from mechanical defects in
the tools, for it was subsequently discovered that the worm frequently
carried a portion of the upper tenacious clay through the softer strata
beneath, and brought it up again. The tenacious clay might have been
called London clay, but no value was attached to that particular
designation; they cared little in engineering for its denomination,
provided it was of a good tenacious quality. This mistake in terms
(supposing it to have occurred) could not have had any influence on
after proceedings; for, before the Tunnel was far advanced, he conducted
with great care a series of borings extending across the Thames, and, as
he used improved tools and worked through tubes, the holes were kept so
dry that a candle was frequently lowered down to the bottom in order to
see the amount of infiltration. By this means he was enabled to
construct a correct section of the bed of the Thames at that spot,
showing every layer of shells and gravel as well as every variation of
the surface of the silt, &c. He entered more at length into these
details than might perhaps appear necessary, because he felt it was
incumbent upon those who had the conduct of works to show that they did
not proceed so ignorantly or so recklessly as had been assumed, in the
design or execution of large undertakings.’
[9] The paragraphs in small type, without any reference, are from Sir
Isambard’s journals. The sentences inserted at the side are his marginal
summary. Occasionally a few words are added (in square brackets) by way
of explanation.
[10] The shaft subsequently made on the Wapping shore was sunk to its
full depth without any under-pinning.
[11] Professor Rankine, in his work on _Civil Engineering_, p. 599,
describes the Thames Tunnel works under the significant heading
‘Tunnelling in Mud.’
[12] _Proceedings Inst. C. E._ i. 34. The circumstances which led Sir
Isambard to conceive the idea of a shield, and the earlier designs he
made for it, are described, with illustrations, by Mr. Law, pp. 7-10.
[13] Mr. Law’s memoir contains a detailed description of every part of
the shield, illustrated by careful drawings.
[14] Mr. Beamish had joined the works on August 7.
[15] On November 20 Mr. Brunel mentions in his diary that he had ‘passed
seven days out of the last ten in the Tunnel. For nine days on an
average 20⅓ hours per day in the Tunnel and 3⅔ to sleep.’
[16] On the previous day Mr. Brunel had been formally appointed resident
engineer.
[17] Mr. Gravatt had been appointed an assistant engineer six months
before.
[18] Sir Isambard’s journal of this eventful night consists--as he was
not himself present--of Mr. Beamish’s journal, with a few words in warm
commendation of that gentleman’s ‘judgment, coolness, and courage,’
followed by observations upon the stability of the shield. He then gives
a statement made by Mr. Gravatt, and taken down in shorthand. No
extracts are given in the text from Mr. Beamish’s narrative, as he has
already inserted it in a condensed form in his _Life of Sir Isambard
Brunel_, pp. 244-248.
[19] Mr. Michael Lane, at this time foreman bricklayer, became one of
Mr. Brunel’s most valued assistants, and was employed by him on the
Monkwearmouth Docks and the Great Western Railway. After filling various
posts in the service of that company, he was in 1860 appointed their
principal engineer, an office which he held till his death, in February,
1868.
[20] On this occasion an amusing incident occurred. Mr. Brunel was
exceedingly unwilling to permit his visitors to make this expedition
into the arch; but on the assurance that they could all swim perfectly
well, he consented to take them, with the understanding that, if he
jumped overboard, they were immediately to follow his example, and swim
after him to the shaft. While they were in the arch Mr. Brunel (as Sir
Isambard mentions) fell overboard. As soon as he recovered himself, and
turned to swim back to the boat, he remembered that he had unwittingly
given to his companions the signal to jump out into the water. He was
much amused, on looking up, to see that they were not swimming after
him, but were still sitting in the boat clinging to the gunwale, with
faces expressive of blank despair.
[21] Mr. Brunel’s comment in his diary is as follows:--‘Without
ascribing any particular merit to myself, I cannot help observing, for
my future guidance, that being alone, and giving few but clear orders,
and those always to the men who were to execute them, I succeeded in an
operation not altogether mean, and which a very trifling want of
precaution or order might have caused to be a total failure.’
[22] On January 15, 1828, the Directors of the Thames Tunnel Company
passed the following resolution, which they ordered to be advertised in
the _Times_, _New Times_, _Herald_, _Ledger_, and _Courier_:--‘That this
court, having heard with great admiration of the intrepid courage and
presence of mind displayed by Mr. Isambard Brunel, the company’s
resident engineer, when the Thames broke into the Tunnel on the morning
of the 12th instant, are desirous to give their public testimony to his
calm and energetic endeavours, and to that generous principle which
induced him to put his own life in more imminent hazard to save the
lives of the men under his immediate care.’
[23] The Thames Tunnel was not successful as a commercial undertaking;
but it has always been considered, especially by foreigners, one of the
most interesting sights in London, and has been visited by several
millions of persons. In 1865 it was purchased by the East London Railway
Company, and trains now (March, 1870) run through it. The possibility of
using the Tunnel as a railway had been considered in Mr. Brunel’s
lifetime, and the idea was approved of by him.
[24] This description is based on the translation given by Mr. Drewry
(_Suspension Bridges_, London, 1832, p. 75), from the _Mémoire sur les
Ponts Suspendus_, by M. Navier (Paris, 1823, p. 49). M. Navier saw the
bridges when they were erected at Sheffield in May 1823.
[25] The dimensions of these designs were as follows:--
(_a._) Length of floor 890 feet.
Distance between points of suspension 980 "
Length of chain 1,300 "
With a capacity to bear excessive load of 650 tons.
(_b._) Length of floor 916 feet.
Distance between points of suspension 1,160 "
Length of chain 1,468 "
With capacity to bear excessive load of 650 tons.
[26] On plate I. is given (fig. 1) a facsimile on a smaller scale of the
drawing sent in by Mr. Brunel for the last-mentioned (_b_) of these two
designs.
[27] See below, p. 60.
[28] See above, p. 42.
[29] The dimensions proposed in this design were as follows:--
Distance between points of suspension 600 feet.
Versed sine 60 "
Width of roadway 32 "
[30] A few days before this ceremony, an iron bar, 1½ inch diameter, and
about 1,000 feet in length, was hung across the valley from Clifton
Rocks to Leigh Down, to facilitate the works. It was traversed by a
basket pulled by ropes. The first few journeys of this machine were
somewhat perilous. It was intended that Mr. and Mrs. Brunel should be
the first passengers; but, when all was ready, one of Mr. Brunel’s
assistants started on a clandestine trial trip, and owing to a bend in
the bar, the basket stuck half way, and the mast of a passing steamer
caught in the rope. The rope was however cut, and he was drawn back.
When the apparatus had been put to rights, on another occasion, when Mr.
Brunel was in the basket, it got jammed, and he had to climb up the
connecting link and get upon the bar, before he could release the
basket.
[31]
Span 702 feet 3 inches.
Versed sine 70 "
Roadway above high-water 248 "
[32] Plate I. fig. 2 (p. 49), shows an elevation of the bridge according
to the designs on which it was commenced.
[33] See Mr. Brunel’s remarks:--_Proceedings Inst. C. E._ for 1841, pp.
78, 79.
[34] Rollers on an arched surface had been used previously in several
bridges.
[35] The chains were used in the construction of the Saltash bridge.
[36] Speech of the Chairman, the late Captain Mark Huish, at the first
general meeting, August 2, 1861.
[37] Some re-arrangement of Mr. Brunel’s design was rendered necessary
in order to adapt the Hungerford bridge chains to the Clifton bridge,
and there are three chains instead of two, as in Mr. Brunel’s design.
The platform is stiffened by wrought-iron girders instead of by timber
trussing, and the whole bridge is stiffened transversely by the
wrought-iron girders at the sides, which are connected throughout by
diagonal bracing. The clear width of the bridge is 30 feet, 5 feet less
than originally intended. It should be added, that no attempt has been
made to complete the towers according to Mr. Brunel’s architectural
designs.
[38] A graphic account of this famous parliamentary contest will be
found in the third volume of Mr. Smiles’ _Lives of the Engineers_,
chapter xi.
[39] See Mr. Smiles’ _Life of George Stephenson_, p. 325.
[40] See Mr. Smiles’ _Lives of the Engineers_, vol. iii. chap. xv.
[41] By means of the railway (it was said) goods would be conveyed with
ease from London to Reading in _three or four hours_, and from Bath to
Bristol in _one hour_.
[42] During Mr. Stephenson’s cross-examination, several questions were
put to him as to the dangerous consequences which might be expected to
result from travelling through a tunnel a thousand yards long. At length
he lost all patience at the ignorance displayed by the questions put to
him by counsel, and the following passage of arms took place:--
‘_Mr. Stephenson._ I wish you had a little engineering knowledge--you
would not talk to me so.
_Counsel._ I feel the disadvantage.
_Mr. Stephenson._ I am sure you must.’
In other parts of the engineering evidence there are some statements
which read strangely enough at the present day, as for example the
following: ‘The noise of two trains passing in a tunnel would shake the
nerves of this assembly. I do not know such a noise. No passenger would
be induced to go twice.’
[43] At this time the Lords’ committees were open to all peers who chose
to sit on them, and it was not considered indecorous for peers who had
not attended any of the previous sittings to vote on the division.
[44] The Great Western Railway was constructed with but few deviations
from the line sanctioned in 1835. The only alteration of any importance
was at the London end, where, by an Act passed in 1836, the line was
taken to Paddington, instead of joining the London and Birmingham
Railway near Kensal Green. This change of plan was rendered necessary by
reason of a difficulty having arisen between the two companies as to the
terms of their agreement, and not, as has been often stated, in
consequence of the adoption of the broad gauge on the Great Western
line.
[45] Sir William Armstrong’s hydraulic machinery at Paddington is
described by him in a communication printed in the _Report of the
British Association_ for 1854, p. 418: ‘I have also applied it [water
pressure machinery] extensively to railway purposes chiefly under the
direction of Mr. Brunel, who has found a multitude of cases involving
lifting or traction power in which it may be made available. Most of
these applications are well exemplified at the new station of the Great
Western Railway Company in London, where the loading and unloading of
trucks, the hoisting into warehouses, the lifting of loaded trucks from
one level to another, the moving of turn-tables, and the hauling of
trucks and traversing machines are all performed, or about to be so, by
means of hydraulic pressure supplied by one central steam engine with
connected accumulators.’
[46] See p. 104.
[47] No copy of this report can be found; but documents of subsequent
date sufficiently indicate the nature of the arguments Mr. Brunel used
in it.
Mr. Brunel had about this time given much attention to the principles of
wheel carriages, as is manifested by an interesting article ‘On Draught’
written by him for the work on ‘The Horse,’ published by the Society for
the Diffusion of Useful Knowledge.
[48] With regard to this point, Mr. Brunel afterwards admitted that he
had held a mistaken opinion. In speaking of his reasons for adopting the
narrow gauge on the Taff Vale Railway in 1838, he said before the Gauge
Commission:--‘One of the reasons, I remember, was one which would not
influence me now; but at that time I certainly assumed that the effect
of curves was such, that the radius of the curve might be measured in
units of the gauge, in which I have since found myself to have been
mistaken.’
[49] See Mr. Brunel’s report of August 1838, printed in Appendix I. p.
528.
This plan was never adopted, as it was found desirable upon the broad
gauge to use still wider carriages overhanging the wheels; but advantage
was taken of the broader base to use wheels of greater diameter.
However, in the saloon carriages, where ease of travelling was the chief
object aimed at, the bodies were placed within the wheels.
[50] In the course of constructing the earth-works of a railway, the
contractors were accustomed to lay down _temporary ways_ or lines of
rail, for the earth waggons to travel upon. When these were done with,
the proper road for the trains was laid down; and this, to distinguish
it from the former one, was called the _permanent way_.
[51] See Wood _On Railways_, 3rd. edit. 1838, p. 151.
[52] A full description of the original road of the Great Western
Railway, communicated by Mr. Brunel, will be found in Wood’s _Treatise
on Railroads_, 3rd edit. 1838, p. 708.
[53] At this time Mr. Brunel was confined to the house by the effects of
his accident on board the ‘Great Western’ steam-ship (see p. 242). Had
he been on the spot, he would have been able to give the work careful
consideration during its progress, and to judge of the expediency of
proceeding with the plan.
[54] The continuity of the timbers diminishes the risk of trains leaving
the line from small imperfections in the permanent way. And, should a
train leave the rails, the injury to the carriages and to the road is
generally less serious than it is when the wheels of a carriage off the
rails come into repeated and violent contact with the cross sleepers.
Instances have frequently occurred where carriages which have left the
rails have run considerable distances on the longitudinal timbers
without injury.
[55] This experiment excited the greatest interest, and it was long
afterwards related how Mr. Brunel, by the stroke of a hammer, had
knocked to pieces the scientific deductions of Dr. Lardner, who, as was
well known, had prompted Mr. Wood’s decision in this matter.
Mr. Brunel was so much impressed with the great influence which the
operation of the blast-pipe had on the working of the locomotive that he
afterwards investigated the whole subject, and made further experiments
to determine whether or not it might be expedient to abandon the steam
blast, and to maintain the draught in the chimney with a fan worked by a
rotary steam jet.
[56] The inconveniences of a break of gauge had already been brought
into notice. One of the narrow-gauge companies, the Midland, worked two
existing lines of railway, one between Birmingham and Gloucester, laid
on the narrow gauge, and another between Bristol and Gloucester, on the
broad gauge; and thus there was a break of gauge at Gloucester.
[57] It should, however, be added, that the Commissioners had stated in
the body of their report: ‘We feel it a duty to observe here, that the
public are mainly indebted for the present rate of speed, and the
increased accommodation of the railway carriages, to the genius of Mr.
Brunel and the liberality of the Great Western Company.’
[58] These experiments will be found in the Appendix to the Report of
the Commissioners of Railways, respecting railway communication between
London and Birmingham (ordered to be printed May 22, 1848).
[59] This was fully borne out afterwards, the express trains running in
the same time, 3 hours, over both routes, though the length of the
broad-gauge line was 129 miles, as against 113 of the narrow. Similar
favourable results have been since exhibited in the competition between
the broad and narrow gauge lines to Exeter.
[60] Among many important advances in railway travelling made on the
Great Western Railway, it may be mentioned that it was on this line that
express trains running long distances without stopping were first
introduced; and that, in 1845, within about a year of the completion of
the line to Exeter, express trains ran from London to Exeter, 194 miles,
in 4½ hours. This rate of travelling, which was accomplished without
difficulty by the broad gauge in its early days, has scarcely been
exceeded since on any railway.
[61] Even in the locomotives when of equal power, Mr. Brunel calculated
that the extra weight was not more than about 500 lbs.
The extra cost of the Great Western Railway was only, including land,
from 300_l._ to 500_l._ per mile, or less than 10 per cent. of the
whole; although Mr. Brunel had taken advantage of the broad gauge to get
carriage bodies 2 feet wider than was then usual.
The wide carriages and waggons were found less costly than the narrow
ones in proportion to the load they carried.
[62] The apparatus patented in 1839 by Mr. Samuel Clegg and Messrs.
Jacob and Joseph Samuda, and improved from time to time by them, was
that adopted in almost all the attempts made in this country to
introduce the Atmospheric System. In reckoning up the force which was
available for mastering the practical difficulties of the undertaking,
the death, in 1844, of Mr. Jacob Samuda must be considered to have been
to his brother, and to all others concerned, a great and irreparable
loss.
[63] A considerable amount of engine power was necessarily consumed in
exhausting the tube before the passage of the train commenced; and it
might at first sight appear that this work was wasted, and that it was
only the work which the engine performed during the passage of the train
which was useful in traction. This, however, was not the case; for, as
was admitted by the more scientific of the opponents of the Atmospheric
System, the power employed in anticipatory pumping was work legitimately
stored up and re-delivered in relief of the engines during the passage
of the train. A waste of power incidental to the Atmospheric System was
indicated by the heat of the air which was delivered by the exhausting
pumps. This waste, however, amounted on the average to only 10 per cent.
of the total work done. A further source of waste of power was the
friction of the air passing along the tube to the exhausting pumps; this
waste was found to amount, on the average, to from 10 to 15 per cent. of
the total work done.
[64] This was almost the only case in which Mr. Stephenson approved of
the application of the System.
Before the Croydon and Epsom Committee, in answer to the question, ‘Does
the Atmospheric railway give you any power of using practically and
usefully steeper inclines than the locomotive railways?’ Mr. Stephenson
said, ‘Yes, I think it does, but still at a very inordinate loss of
power; still it is within the scope of the Atmospheric System under
particular circumstances. I remember a case where it might be
advantageous. Mr. Brunel went to Italy for the purpose of laying out a
line there, and from Genoa over the Apennines he had to form a line; it
would probably rise 15 or 20 miles at 1 in 100 or 1 in 60 or 70. Where
there is that continuous line of ascent, where no stoppages are
required, where the locomotive is totally inapplicable, there I can
conceive nothing more eligible than the Atmospheric plan’ (p. 80).
[65] The length of the line was 52 miles, but as it was considered that
auxiliary stationary power would in any case be necessary on the 10½
miles of very steep inclines, the cost of the Atmospheric apparatus is
taken on 41½ miles.
[66] It must be remembered that beyond the South Devon Railway was the
projected railway through Cornwall, which, with its long and heavy
gradients, was, in all its features, even more suitable than the South
Devon for the application of the Atmospheric System. Had that system
succeeded, and been introduced on the Cornwall Railway, a very great
saving might have been made in the cost of the works of this line.
[67] _I.e._ before the Croydon and Epsom Committee. See above, p. 138.
[68] It will be found on pp. 35-52 of the Minutes of Evidence taken
before the Atmospheric Committee (ordered to be printed April 24, 1845).
[69] This appeared with sufficient clearness from the general comparison
between vacuum, weight of train, and speed. The exact appropriation of
the force employed was shown by some dynamometric experiments made on
the line.
The highest speed recorded was 68 miles per hour, with a train of 28
tons, the speed averaging 64 miles per hour for four level miles of the
line, the vacuum being 16 inches. This speed should have exhibited a
resistance of about 21 lbs. per ton, or 588 lbs., as the running
resistance or friction, and 645 lbs. for the resistance of the air; in
all 1,233 lbs. Now, the pressure due to 16 inches of vacuum on the
piston is 1,390 lbs., which gives 157 lbs. as the friction of the
piston; a result which corresponds sufficiently well with a direct
dynamometric experiment.
Going to the other extreme, there are numerous records of trains of 100
tons which attained, on a level of four miles in length, average speeds
of from 30 to 35 miles per hour, with 16·5 inches of vacuum, one train
of 103 tons going 32·4 miles per hour with 16·9 inches of vacuum.
[70] This valve consisted of a number of long delicate blades of spring
steel, arranged parallel to each other, as in a musical box, but with
wider intervals. These plates rested on a series of truly faced bars,
which crossed the end of the air-passage. The slightest pressure
outwards lifted the springs; and as the area of opening was large, a
very free passage was given to the air. On the current ceasing, the
blades instantly, yet without shock, replaced themselves in contact with
the bars, clipping them tightly under a very small reverse pressure, and
effectually closing the passage. Their merit consisted in their being
almost without weight, and thus promptly re-closing the aperture by a
delicate elastic reaction.
[71] Trains frequently arrived late on the Atmospheric portion of the
South Devon Railway, owing to its being at the end of the long trunk
line from London to Exeter, and having at its other end a locomotive
line contending with very heavy gradients.
[72] It may be mentioned that, from the date of the abandonment of the
Atmospheric System, he refused to receive any remuneration for his
professional services as engineer beyond a nominal retaining fee.
[73] See above, p. 138.
[74] These quantities are the result of the experiments made in
September 1847. They agree with what is now the received opinion of
authorities on train resistances, and represent favourably the case for
the locomotives at the time of Mr. Brunel’s report in August 1844. At
the time when Mr. Brunel wrote his report of August 1844, the weight of
a locomotive, as has been said, bore a higher ratio to its power.
[75] It must be borne in mind that all the inconveniences attending the
use of auxiliary locomotives must be encountered, or else the excessive
dead weight of an engine powerful enough to take a train up the steepest
gradient in a hilly district must accompany it for the whole length of
that part of the line.
[76] No dynamometer was used in these experiments, but all other
requisite data were recorded with the greatest exactness, and the
horse-power employed may be deduced by means of the scale of resistance
which the subsequent dynamomotric trials supply. Moreover, the result
above arrived at for the consumption of coke is verified by an
examination of published indicator diagrams taken off the same engine on
another occasion.
[77] It would of course be impossible here to give a description of all
Mr. Brunel’s bridges, or even to refer to the most important of them
with that minuteness which would be required if this were a book written
for professional use. The following publications may be
consulted:--Bourne’s _History and Description of the Great Western
Railway_, 1846; Brees’ _Railway Practice_, 1837; Simms’ _Public Works of
Great Britain_, 1838; _Proceedings of Institution of Civil Engineers_,
vols. 14, 25, and generally; Molinos et Pronnier, _Construction des
Ponts Métalliques_, 1857; Humber’s _Cast and Wrought-Iron Bridge
Construction_, 1861; and Humber’s _Record of Engineering_ for 1866. At
the end of the description of many of the bridges in this chapter a note
has been given of publications in which the bridge has been referred to.
[78] In the early days of the Great Western Railway special designs were
made for every one of the ordinary bridges over and under the railway;
but when, in consequence of the rapid extension of the Great Western
system, the number of bridges to be designed became very large, Mr.
Brunel had a set of ‘standard drawings’ prepared and engraved, which
embodied the experience gained, and contained designs suitable for
various situations. The contract drawings were made by adapting to the
particular circumstances of each case the standard drawing which was
most applicable to it. This system, besides securing uniformity of
construction, introduced a considerable amount of economy; since, the
standard drawings being based upon the results arrived at in an
extensive practice, the proper structural arrangements and dimensions
were indicated with far greater accuracy than could be attained in a
reasonable time by an independent calculation in each individual case.
[79] It was called the ‘Wharncliffe Viaduct,’ in acknowledgment of the
services rendered to the Company by the late Lord Wharncliffe as
Chairman of the Committee in the House of Lords. Drawings of this bridge
are given in Simms’ _Public Works of Great Britain_, 1838, pl. 54, 55,
and 56; and in Bourne’s _History and Description of the Great Western
Railway_, 1846.
[80] At the back of retaining walls, such as the abutments and wing
walls of bridges which were subject to the pressure of earth behind
them, Mr. Brunel introduced what were termed ‘sailing courses,’
projecting shelves corbelled out at the back of the wall. The weight of
earth resting on these shelves virtually increased the weight of the
back of the wall, and assisted it in resisting the forward pressure of
the earth.
[81] During the construction of the bridge a part of the crown of the
eastern arch proved defective, in consequence of the cement in the
middle of the brickwork not having set sufficiently at the time when the
centering was eased. Apprehensions which had been entertained by some as
to the safety of the structure were groundless, for when the defective
part was taken out and replaced, no further trouble was experienced. The
bridge has stood well, and has shown none of those symptoms which an
overstrained structure exhibits.
[82] Simms’ _Public Works of Great Britain_, pl. 57, 58; Bourne’s
_History and Description of the Great Western Railway_, p. 36.
[83] When Mr. Brunel for architectural effect employed Gothic or pointed
arches, he occasionally made the main part of the arch of a form
different from the curve visible on the face, but he more frequently
made it of the same pointed form throughout. In this case he did not
obtain equilibrium by loading the crown, but he kept the line of
pressure sufficiently within the thickness of the arch by strengthening
the haunches.
[84] Brees’ _Railway Practice_, pl. 42.
[85] There is an illustration of this bridge in Bourne’s _History and
Description of the Great Western Railway_.
[86] Joggles are small pieces of hard wood or cast-iron of rectangular
cross section, placed between two beams, and fitted carefully into
notches cut across them. The beams are then bolted firmly together. The
object is to stop the slipping which would occur between the two
surfaces if the beams were merely laid one on the other and loaded, and
so to make two pieces of equal size act as one of double the depth, and
therefore of four times the strength of a single piece. In 1841 Mr.
Brunel made experiments to satisfy himself of the strength gained by
this method; and he afterwards perfected the arrangement by ensuring an
exact fit in the notches by tightening up the joggles with wrought-iron
wedges.
[87] A drawing of this bridge is appended to the _Report of the
Commission on the Application of Iron to Railway Structures, 1849_.
[88] Mr. Brunel, by taking care in his timber structures to distribute
the load uniformly, was frequently able to dispense with costly
foundations. On one occasion a timber viaduct 30 feet high was placed
upon a broad platform resting on an old embankment upwards of 50 feet in
height. A similar arrangement was adopted by him in some cases on slips
in embankments which it would have been uncertain and expensive to make
up with earthwork.
[89] For a description of this viaduct, see _Proceedings Inst. C. E._,
vol. xiv. for 1854-5, p. 492.
[90] Mr. Brunel about this time introduced a great improvement in the
manufacture of wrought-iron bolts for bridges, when these, as is usually
the case are screwed at the ends. A screw cannot be made on a bolt
without the metal being cut into to the extent of the depth of the
thread, and the strength thereby considerably reduced. The section,
taken at the bottom of the thread, is much smaller than that of the
bolt; and, moreover, owing to the abrupt change at the commencement of
the thread, the strength is not so great as that due to the reduced
sectional area. The improvement consisted in swelling out the iron of
the end of the bolt where the thread was to be made, so that the
diameter, at the deepest part of the thread, should be fully equal to
that of the bolt. The saving of metal by this improvement, especially in
the case of long bolts, is very considerable.
[91] An arrangement was introduced by Mr. Brunel to prevent any
disturbance in the permanent way by a settlement of the embankments at
the ends of the viaducts. There were no large abutments and wing walls,
but the end of the viaduct was formed with a queen truss in the parapet,
which rested on a platform on the top of the embankment slope. In any
slight settlement of the earth, the end of the viaduct sunk with it, and
the permanent way was not disturbed. Wedges were provided to raise the
ends of the trusses and readjust their level. This was an important
provision, as it applied to about 60 cases on the Cornwall Railway.
[92] The simple arrangement of the timber-work was specially arranged
with a view to giving facility for replacing portions of it, should they
decay.
[93] The viaducts on the Cornwall Railway between Plymouth and Truro are
thirty-four in number. Of these there are nineteen which have from six
to twenty openings, and are from 80 to 153 feet in height. The aggregate
length of these nineteen viaducts is nearly 2¾ miles.
[94] A drawing showing this form of section is appended to the _Report
of the Commission on the Application of Iron to Railway Structures_,
1849.
[95] The remainder of this letter is printed in Chapter XVI. p. 486.
[96] Mr. Brunel was thoroughly conversant with the principles of
mathematical analysis, and was able with great readiness to apply it in
practice; but at the same time he preferred, when it was possible, to
use geometrical methods of solution for engineering problems.
[97] In the note at the end of this chapter mention is made of some
experiments made by Mr. Brunel on riveted joints.
[98] See above, p. 185.
[99] A description of this bridge is given in Humber’s _Bridge
Construction_, vol. i. p. 228, and vol. ii. pl. 70, 71, 72; Molinos et
Pronnier, _Construction des Ponts Métalliques_, p. 328, pl. 20, 21, 22.
[100] See _Proceedings Inst. C.E._, for 1847-8, vol. vii. p. 138.
[101] After some perseverance, Mr. Brunel succeeded in getting these
unusually large links, which were 20 feet long, rolled in a single piece
without welding on the eyes. He had to go down himself to the
manufactory in order to get the men into the way of doing the work.
[102] See note at the end of this chapter for experiments on ropes and
chains. The crabs were designed and made specially for this duty. Each
had two barrels, grooved to receive the chain, which was passed several
times round both barrels, so as to get sufficient grip; and it was in
this way possible to wind in with the crabs any length of chain without
having to stop to fleet, as would have been the case had a
single-barrelled crab been used.
These crabs were subsequently used at the floating of the Saltash
trusses, and at the launch of the ‘Great Eastern.’
A similar arrangement was applied in the paying-out machinery of the
Atlantic cable, and is still used for the picking-up gear in the ‘Great
Eastern.’
[103] See _Encyclopædia Britannica_, ‘Iron Bridges,’ vol. xii. p. 601;
Molinos et Pronnier, _Construction des Ponts Métalliques_, p. 320, pl.
23, 24, 25.
[104] These would have been magnificent specimens of timber-work, and a
design for somewhat similar trusses had at one time been prepared for
the Chepstow Bridge. It is worthy of mention that Sir Isambard Brunel at
one time designed a timber arched bridge of 800 feet span to cross the
Neva at St. Petersburg.
[105] Before the work was begun Mr. Brunel made calculations to
determine whether or not it might be desirable to cross the river with
one span of 850 feet, in order to avoid the great depth at the centre
pier.
A few extracts from letters relating to bridges of large span will be
interesting:
‘January 31, 1852.
‘I have revised my calculation as to a span of 1,000 feet, and find
that even with the loads and limitations of strains which I
adopt--namely a proper thickness of ballast, and a possible load of
a train of engines without tenders, and a limitation under such a
load of 5 tons’ strain per square inch, that a span of 1,000 feet
may be made in England of the very best workmanship, and sent out
and erected for I should say safely 250,000_l_., of course a single
way--another 250,000_l_. ought, I should think, to cover the rest
of the bridge.
I should like to explain to you the mode I should propose for
raising such a bridge, weighing 7,000 tons.
‘December 1, 1852.
As you ask me my opinion of the advisability of patenting your
bridge, I give it you; though you will probably be the first person
who will have followed such advice if you do so, and might safely
patent such a novel mode of using advice.
In my opinion you cannot patent the bridge. Without detracting in
the least from your merit of invention, the form has been so
frequently and exactly applied that no patent could hold. The
Saltash bridge now just advertised for letting is exactly on the
same principle as regards form; and this is so old to my knowledge
that I can claim no invention, and the use of cast iron for such
purpose is also incapable of being patented. There is much that is
good in your bridge, and you deserve credit, but you would find
innumerable claimants to dispute, and successfully, your attempt to
claim a monopoly by a patent--I myself for one. Besides, I see it
published in a book.
‘May 30, 1854.
‘As to your present enquiry, I do not think that what I am doing at
Saltash would be applicable in this case; but without being guilty
of great presumption, I think I may say that if the same plan will
not do, it is fair to assume that the same brains which concocted
the plan to suit the difficulties of the Tamar might very likely
find the means of overcoming those of the Severn.
If I should be able to suggest a feasible plan, and there should be
found people ready to make it, I shall have the satisfaction of
bridging the Severn as well as the Tamar.’
[106] It has of course been impossible to refer to the points on which
Mr. Brunel was aided, in his different works, by the suggestions of his
assistants; but it may be mentioned here that, as appears from one of
Mr. Brunel’s letters, the plan of working under a diving-bell had been
proposed by Mr. William Glennie, his assistant, before he knew that Mr.
Brunel had decided to adopt it.
Mr. Brunel also mentions in another letter that the ‘very simple and
effectual manner’ of applying the pneumatic apparatus, by forming the
annular space round the circumference of the bottom of the cylinder, was
suggested to him by Mr. Brereton, when the method of constructing the
cylinder was being finally settled.
[107] In the _Proceedings of the Institution of Civil Engineers_, vol.
xxi. 1861-2, will be found a paper by Mr. Brereton, giving a detailed
description of the means employed for the construction of the central
pier.
[108] Shortly after Mr. Brunel’s death some of his friends on the Board
of the Cornwall Railway placed the following inscription, in raised
letters, over the lard archways--I. K. BRUNEL, ENGINEER, 1859.
[109] A portion of the chains used were those which had been made for
the Clifton Suspension Bridge, Mr. Brunel’s earliest design.
[110] Though it is convenient to explain the nature of the strains in
the Saltash bridge as an arch and suspension bridge combined, it is not
intended to imply that there is any virtual difference between this
truss and the one at Chepstow, for in both the strain on the tube
counteracts the strain on the chains, though the one tube is curved and
the other straight.
[111] Humber’s _Bridge Construction_, vol. i. p. 231; vol. ii. pl. 78,
79, 80.
[112] This load amounted to two and three quarter tons per foot run, in
addition to the weight of the truss. Under this load the central
deflection was about 5 inches.
The strain on the iron of the tube and of the chains with a load of one
ton per foot run, in addition to the weight of the truss, flooring, and
ballast, is under four tons per square inch.
[113] The difficult operations of floating and lifting the
superstructures of the Chepstow and Saltash bridges were carried out
entirely by Mr. Brunel and his assistants, there being no contractor
engaged in, or responsible for, the work in either case.
[114] A photograph taken shortly after the floating of the second tube
forms the frontispiece of the first volume of Humber’s _Bridge
Construction_.
[115] See above pp. 190 and 193.
[116] It has been observed with much truth that full justice has not
been done to Mr. Brunel’s exertions in this department of practical
science.--See ‘Address of George Parker Bidder, Esq., on his election as
President of the Institution of Civil Engineers, January 10, 1860.’
[117] Captain Claxton died on March 27, 1868, in his 79th year. The
manuscript of this and the three following chapters was fortunately
completed in time to be submitted to him. He spared no trouble either in
giving or procuring original documents and other materials for all parts
of this book, in the preparation of which he took the liveliest
interest.
[118] To enable the ship to resist the action of the heavy Atlantic
waves, especial pains were taken to give her great longitudinal
strength. The ribs were of oak, of scantling equal to that of
line-of-battle ships. They were placed close together, and caulked
within and without before the planking was put on. They were dowelled
and bolted in pairs; and there were also four rows of 1½-inch iron
bolts, 24 feet long, and scarfing about 4 feet, which ran longitudinally
through the whole length of the bottom frames of the ship. She was
closely trussed with iron and wooden diagonals and shelf pieces, which,
with the whole of her upper works, were fastened with bolts and nuts to
a much greater extent than had hitherto been the practice.
The principal dimensions of the hull and engines are given in the note
to this chapter (p. 245).
[119] The engines as designed by Messrs. Maudslay were beam engines,
although Mr. Brunel had strongly urged them to adopt the more compact
form of direct-acting engines. They, however, thought it better not to
depart from what was then the usual form.
[120] _Steam and its Uses_, by Dr. Lardner, 1856. Chapter on ‘Steam
Navigation,’ section 10.
[121] ‘An exposition of the advantages of the proposed Railway from
Limerick to Waterford.’
[122] _The Steam Engine: its Application to Navigation and Railways,
with Plain Maxims for Railway Speculators_, 5th edition, 1836, p. 307.
[123] It is right to add that, according to the report given in the
_Athenæum_ newspaper of the meetings of the British Association at
Liverpool in September 1837, ‘Dr. Lardner addressed the section
(Mechanical) on his old subject, the application of steam to long
voyages. His remarks and calculations were to a great extent identical
with those brought forward by him last year at Bristol, and published
long since in his work on the steam-engine, but the conclusions were
somewhat varied. The Doctor did not now deny that the voyage might be
practicable, but he did not believe that it would be profitable’
(_Athenæum_, September 23, 1837). Dr. Lardner was answered by several
speakers, and among them by Mr. Guppy, who pointed out in much detail
the unreliable character of Dr. Lardner’s data; while nothing was
suggested about commercial profits or subsidies. It may therefore be
inferred that Dr. Lardner’s arguments as to the consumption of fuel
remained the same, although he may have abandoned the conclusion which
legitimately followed from them--namely, that the long voyages were
practically impossible.
The Report in the _Bristol Mirror_ newspaper of the same date (copied
from the _Liverpool Standard_) is as follows:--‘Dr. Lardner’s speech was
little beyond a repetition of his discourse last year in Bristol,
re-published by him in the _Edinburgh Review_. The voyage to America by
steam he treated as practicable, but so uncertain as to render a
profitable result hopeless.... During nearly all the year there was an
adverse west wind, and the Gulf Stream was to be avoided.’
[124] She had only _seven_ passengers on board; fifty, it is stated,
were deterred from going in her by hearing of the fire.
[125] These engines were to have had two cylinders of 88 inches
diameter.
[126] It is interesting, in connection with this subject, to mention the
following circumstance. At Mr. Brunel’s recommendation, Mr. Humphrys
consulted Mr. James Nasmyth as to the best means of forging the large
paddle-shaft; as they could not get any manufacturer to undertake it. To
accomplish this forging Mr. Nasmyth designed his steam-hammer, and
though it was not then erected in Bristol, in consequence of the
alteration of the form of the engines of the ‘Great Britain,’ it soon
afterwards came into general use.
[127] In the Minute Book of this date it is mentioned as a reason for
postponing any decision on the subject, that Mr. Brunel was making
‘final,’ and afterwards ‘further,’ experiments.
[128] See Mr. Guppy’s paper, printed in the _Proceedings of the
Institution of Civil Engineers for_ 1845, p. 151.
[129] This report is printed in Appendix II. p. 539. The paragraphs in
which Mr. Brunel describes the advantages of the screw propeller will be
found at page 552.
[130] A description of Mr. Humphrys’ trunk engines is given in
Tredgold’s work on the steam engine (ed. 1838), p. 390.
[131] The balanced rudder, which is peculiarly applicable to screw
ships, has encountered much opposition; but it has lately been
successfully introduced by Mr. E. J. Reed, C.B., into vessels designed
by him for the Royal Navy.
[132] It maybe convenient here to state that the dock in which the
‘Great Britain’ was built led into the Floating Harbour, which is a
portion of the channel of the river Avon closed in. The Floating Harbour
communicates through the Cumberland Basin with the river.
[133] One of the consequences of the publication of this report was,
that Mr. Brunel received so many letters containing suggestions for
lifting and floating the ship, that he was obliged to have a circular
letter printed declining assistance; and more than four hundred letters
were also received by the Company’s secretary.
[134] ‘The “Great Britain” Steam-Ship. Extracts from the letters of
Captain Claxton, R.N., to I. K. Brunel, Esq., and the Directors.
Bristol, 1847.’
Mr. Bremner’s apparatus is also described in a paper read by him at the
Institution of Civil Engineers, and printed in the twenty-first volume
of the _Transactions_, p. 160.
Accurate illustrations of the break-water and floating apparatus will be
found in the _Illustrated London News_ of August 21, 1847.
In publishing the correspondence to which reference has been made, the
Directors acknowledge their obligations to all concerned in the arduous
task of saving the ‘Great Britain;’ and they add--‘to Mr. Brunel above
all their thanks are most due, for opening their eyes to what might be
accomplished, and for taking upon himself the responsibility of her
release, provided that Captain Claxton was employed to carry out his
views.’
[135] Sir E. Parry was at that time Controller of Steam Machinery, and a
warm supporter of those who desired to make a fair trial of the screw
propeller.
[136] Bourne, on the _Screw Propeller_, ed. 1867, p. 263.
[137] The records of these trials, found among Mr. Brunel’s papers, show
results which coincide in all material points with those given by Mr.
Bourne at p. 284 of his work on the _Screw Propeller_, ed. 1867.
[138] Bourne, Appendix, p. xxxiii.
[139] The letter to Mr. Guppy of August 1843 (given above, p. 259)
contains a reference to some of Mr. Brunel’s ideas upon iron
shipbuilding, subsequent to the date of the design of the ‘Great
Britain.’
[140] Extract from a memorandum by Mr. Brunel (dated February 25, 1854)
on the early history of the great ship.
[141] So Mr. Brunel wrote to the secretary when excusing his own absence
from the meeting on account of illness.
[142] Mr. Brunel concludes this report by indicating the best mode of
contracting for the construction of the ship and engines, and suggests
that an examination should be made of the river Hooghly.
[143] From the great length of this report it has been necessary to omit
the less important paragraphs.
[144] The passages which are omitted refer to the relative cost and
merits of the different tenders.
[145] Two years later Mr. Brunel spoke of the success of the screw
engines as ‘a most grave question upon which hangs I fear to think how
much.’
[146] Mr. Geach was one of the most zealous friends of the great ship.
His death, within a year after the commencement of the work, was the
first of her many misfortunes.
[147] Stringent conditions as to jacketing were introduced into the
contracts; but they were not enforced by Mr. Brunel, in deference to the
strong objections urged by the makers. He much regretted this
concession.
[148] The destination of the ship as proposed at this time was
Australia.
[149] The power of blowing off the steam without noise is of great
importance, and Mr. Brunel made many experiments on the point. The noise
of the steam blowing off, when the engines of a ship are stopped for
fear of an impending collision or other accident, is so great, that it
is almost impossible to hear any orders that may be given.
[150] The screw propeller of ‘Agamemnon’ was broken in a trial trip
outside Plymouth Sound, on November 9, 1853; and the result was that,
from not having efficient governors, the engines flew round at an
alarming speed.
[151] Mr. Russell’s works. The ship was built in a yard immediately
adjoining them.
[152] See, for example, an article in the _Quarterly Review_ of March
1856, entitled ‘The Triton and the Minnows.’
[153] It must be remembered that this report describes the ship as she
was at that time designed by Mr. Brunel.
[154] Extract from memoranda of October 5, 1855:--
‘By constant observation, to lay down position and course of ship, and
correct compasses.
‘To record speed of ship through water by logs.
‘Revolution of engines.
‘Force and direction of wind.
‘Draught and trim of ship, sails carried, &c.
‘Temperature and peculiarities of sea water.
‘As the result of these observations, to plot down hour by hour the
position of the ship, to compute the speed, variations of compass, the
direction and force of current, and true direction and force of the
wind.’
[155] Mr. Brunel also proposed to have charts prepared for the route of
the great ship to Australia and Calcutta, similar in character to some
which were made under his directions for the route of the ‘Great
Western’ to New York, which he described as follows:--
‘When we started the “Great Western” to New York, I had a chart drawn
and engraved of the sea (that is, the lines of latitude and longitude,
and the bearings of the compass, and the coast and soundings) on a
cylindrical projection of a great circle from Bristol to New York; and
we found it very useful for the captain to _see_ his great circle
sailing, and to see how much he was deviating from it.’
[156] Captain Harrison’s command of the ‘Great Eastern’ after she left
the river was unhappily of but short duration, as he was drowned by the
accidental upsetting of his boat in Southampton Water on January 21,
1860, four months after Mr. Brunel’s death.
[157] With this paper Mr. Brunel enclosed a letter, in which he points
out with great earnestness the responsibility of his own position.
After calling the Directors’ attention to the important step they were
about to take, he proceeds:--
‘I am not pointing out a danger without being prepared to propose a
remedy. The same man who, after he has been selected and appointed on
account of his previous character as a sailor, and as an experienced
naval man, would probably feel disposed to reject advice coming from
those who do not profess to be sailors, and to resist directions which
might appear to him as trenching upon his authority, or as implying
doubts of his ability, could have no such feeling (if he is a sensible
man and fit for the position) if his attention had been drawn to these
views before his appointment, and if he accepts the trust reposed in him
on the understanding that he is expected to pay attention to these
opinions, and if, as I shall urge upon the Directors to ascertain, he
entertains no objection to the adoption of them, and agrees to follow
the principles of action which I hope to induce the Directors to adopt
as rules in the navigation of the ship.
‘I propose therefore to lay before the Directors the result of my
anxious consideration of this subject, to urge upon them the adoption of
my views, and, if they adopt them, to urge that they should make it a
condition in the selection and appointment of a commander that such
views are approved of and adopted by him.
‘This is a strong and plainly stated request, but not more strongly put
than I feel that the occasion requires.
‘I have an immense stake in the success of this enterprise. I do not
refer merely to my pecuniary investment; but, as affecting my
professional reputation, my stake is much deeper; as, although I was
accidentally led by circumstances into proposing the plan we have
adopted, and the Company was not originally formed to carry it out, and
although the plan when proposed was well weighed and considered by men
competent to judge, at all events, upon the prospects as a commercial
speculation, and although it was adopted by them, and therefore they
must share in the responsibility, and although many may share with me in
the credit of our success; yet there is no doubt that I should have to
bear solely and very heavily the blame of a failure. On this ground
alone, therefore, the Directors, I am sure, will willingly allow me to
urge my views strongly, and will excuse the length at which I do so. But
I shall rely upon satisfying them that my views and opinion should
command their concurrence on their own merits; and with this preface,
which has already reached an undue length, I will lay before them a
paper on the subject, most of which has been written for some time in
anticipation of the present circumstances, and having been thus written
at different periods is, I fear, somewhat disjointed, and wanting in
arrangement, and therefore much longer than it might have been.’
[158] Shortly after the publication of this report, Mr. Brunel received
a letter from Mr. G. W. Bull, of Buffalo, U.S.A., encouraging him to
adopt the plan of launching sideways, as that was the way in which the
large steamboats of the American lakes were launched. In the course of a
correspondence which ensued, Mr. Bull gave much information as to the
manner in which these launches were effected. He advocated a free launch
for the ‘Great Eastern.’
[159] For an account of this and other experiments and observations on
friction, see note A at the end of this chapter.
[160] The power mentioned here as applied for starting the ship was two
hydraulic presses, to overcome adhesion at the first start. The river
tackle was relied on to overcome the friction.
[161] See below, note A, p. 389.
[162] The reason for stopping was lest the ship should float at high
water during the night.
[163] It remained a doubtful point whether or not the bow cradle was
stopped by the brakes. Subsequent experience favoured the opinion that
it had stopped of itself.
[164] The ship had always been spoken of as the ‘Great Eastern,’ and
this name was specially agreeable to Mr. Brunel. It was not a point on
which he set much store, but his views were pretty well known; and, as
the name had not been of his choosing, but had rather grown out of the
name of the Company, and the natural association of ideas with his first
ship, the ‘Great Western,’ it might reasonably have been supposed that
it would have been adopted. But some fastidious person suggested that
the name was objectionable, as consisting of two adjectives. A list of
names was prepared and submitted to Mr. Brunel on the day of the launch
at the moment when he was busiest. He said off-hand that they might call
it ‘Tom Thumb’ if they liked. The Directors, however, selected the name
‘Leviathan,’ and so the ship was christened. The new name never stuck to
the ship, and she was registered as the ‘Great Eastern.’
[165] The action of an hydraulic press is limited to the length of
stroke of the ram. Hence, as soon as the ship moved a distance equal to
the length of the stroke, it became necessary to relieve the water
pressure in the cylinder, to pull back the ram into it, and to insert
between the ram of the press and the cradle an additional length of
timber. This operation of pulling back the ram and putting in another
length of timber was called ‘fleeting’ the press, a term used in many
mechanical operations when the motive arrangements are reinstated in
their primary position ready for a further advance in the work.
[166] On this occasion Mr. Brunel had his way, and there were not a
dozen spectators in the yard.
[167] See note A at the end of the chapter.
[168] At this time the friction when the ship was in motion was not much
greater than it had been on previous occasions; but, the adhesion being
greatly increased, a large excess of power became stored up in the
elasticity of the abutments and the chains. This excess of power, on the
ship commencing to move, discharged itself in giving her velocity, and
therefore she moved by short slips, instead of by a gradual motion, as
had been the case previously, when the resistance due to friction and
that due to adhesion had been more nearly equal. For observations on the
friction, see note A at the end of the chapter.
[169] Mr. Stephenson went with Mr. Brunel into all the facts relative to
the operations and all the experience gained therefrom, and examined
carefully the investigations which had been made by means of
self-recording apparatus, and which showed that the friction diminished
as the velocity increased. So struck was Mr. Stephenson at these results
that he urged Mr. Brunel on no account to neglect having the brakes
properly attended to; lest the great adhesion should cause a large
amount of stored-up power, which might give the ship such a velocity
that the force of gravity might exceed that of the friction. The brakes
had not been hitherto neglected; but, in conformity with Mr.
Stephenson’s suggestion, it was thenceforward made a rule that, when a
moderate amount of slack had been overhauled from the drums, the brakes
should be put down, on a signal being given that the pressure in the
presses was rising.
[170] Mr. Brunel received a great many suggestions for launching the
ship. Puncheons, gas, artillery, and especially levers, were among the
appliances recommended. With the desire of behaving civilly to
well-meaning persons who were wishing to do him a service, Mr. Brunel
adopted a plan similar to that which he had found useful when the ‘Great
Britain’ was on shore. He had a circular letter printed, thanking his
correspondents for their suggestions, but saying that the number of such
communications had become so great that it was impossible for him to do
more than cause the receipt to be acknowledged, with thanks for the
intentions of the parties writing.
This plan had, however, the effect of increasing the number of his
correspondents, as several of them wrote a second time to express their
regret that their letters had had no better effect than to be classed
with the numerous communications which Mr. Brunel said he had received
on the same subject, which had seemed unworthy of his notice; and they
explained that though other people’s schemes were, no doubt, worthless,
still that their own, if adopted, would launch the ship.
[171] The number of the presses being almost doubled, but the resistance
of the ship not being much greater than before, the elastic compression
of the abutments was less than it had been previously, so that when the
ship moved there was much less work stored up to give it velocity;
therefore the slides were shorter than they had been before.
[172] Among the many congratulations which Mr. Brunel received on the
completion of the launch, there was perhaps none which pleased him more
than the following letter from Mr. Robert Stephenson, who had been
prevented by illness from being present at the concluding operations,
the critical character of which he had fully appreciated:--
February 1, 1858.
MY DEAR BRUNEL,--I slept last night like a top, after I received
your message. I got desperately anxious all day, but my doctor
would not permit me to venture so far away as Millwall.
I do, my good friend, most sincerely congratulate you on the
arrival of the conclusion of your anxiety.
Yours sincerely,
ROBERT STEPHENSON.
A letter from Mr. Brunel to his friend Mr. Froude, describing the
floating, is given in note B to this chapter.
[173] The principal dimensions of the ship and engines are given in the
note to this chapter, p. 416.
[174] During the last-mentioned voyage, returning from Quebec, a
north-easterly wind blew with a velocity of from 30 to 40 miles an hour.
For the first 24 hours the ship paid no attention to the sea; the next
day, the wind remaining the same, but the sea having got more swell on,
the ship began to roll slowly and sedately, the rolls gradually
increasing up to about 9 degrees on either side of the perpendicular,
and dying out again, and then recommencing.
[175] Between the screw and the rudder was what was termed the after
stern-post, which had no duty to perform except to steady the heel of
the ship, into which the rudder was stepped.
[176] Before the ship was finished, Mr. Brunel had her stability and
rolling carefully investigated. Calculations were made to ascertain the
position of her centre of gravity and the other necessary elements for
determining her stability and period of rolling.
He also had a model made, with arrangements for altering the levels of
weights placed inside. By this means the results of the calculations
were verified. It was determined that the ship would make a single roll
from one side to the other in about six seconds. While she was in the
Thames a steamer struck the hulk alongside and gave the great ship a
slight impulse. Mr. Brunel, who was on board, took advantage of the
opportunity to observe the period of the roll she made, and was pleased
at finding it agree with the calculated period. It is to the
investigations initiated at that time by Mr. Brunel that are due the
great steps since made in the knowledge of the laws which govern the
rolling of ships. Had Mr. Brunel lived he would no doubt have taken the
same pains to record the rolling of the ‘Great Eastern’ as he had in the
case of the ‘Great Western’ when, in 1839, he sent an assistant to
America and back, who took observations of the rolling and pitching of
that vessel in several voyages. These observations were made by a simple
angle-measuring instrument, adjusted by the visible level line of the
horizon, and not by the fallacious method of noting down the swings of a
pendulum.
The ‘Great Eastern’ remains almost perfectly steady in ordinary rough
seas. When the seas become very long, so that their period is nearly the
same as that of the ship, she rolls; though the number of degrees on
either side of the perpendicular is not large. By stowing the weights of
cargo high in the ship, the tendency to roll has been much diminished,
and when engaged in cable laying, with the enormous weights in the cable
tanks all placed above the lower deck, she is remarkably steady.
[177] _History of the Atlantic Telegraph:_ New York, 1866.
[178] It may be desirable to give a short explanation of these works,
which consisted principally of a sluice, a trunk, and a drag-boat.
The Sluice was made in the abutment of Prince’s Street Bridge, and was
intended to create a scour after the water had been let off from either
side of the float, the opening at the bridge being closed by a caisson
which had long been in use when (as was formerly the case) the upper
part of the float was scoured through Bathurst Basin.
The Trunk, near the entrance from Cumberland Basin, is a wooden culvert
between the floating harbour and the river. As much of the mud as could
be dragged there was deposited at the entrance of the trunk, and, when
the tide was low in the new channel of the Avon, sluices were opened,
and the water rushed through from the floating harbour, carrying the mud
with it.
The Drag-Boat was fitted with a steam-engine which worked a large
windlass with three compartments, round two of which chains were passed
and fixed to posts on the quays, and the boat was dragged backwards and
forwards. The third compartment of the windlass worked a chain which
elevated or depressed a scraper, attached to a long pole at the stern,
and secured from swerving by a chain-bridle which passed under the boat.
The scraper stirred up the mud, and deposited the more solid parts at
the entrance of the trunk.
Mr. Brunel also desired that the float boards of the Neetham Dam should
be put into proper working order; and that they should be altered so
that, in times of land floods, the whole or a considerable portion of
the excess of water should be retained, and passed through the feeder;
and that even the water of spring tides should be allowed to pass the
dam, and then be stopped back for the same purpose.
[179] The advantage of forming an air-chamber in the lower part of the
gate, and allowing the water to enter above it, is that when the size of
the air-chamber is properly adjusted to the weight of the gate, there
need not come on the wheels, while moving, more than a trifling amount
of weight.
[180] The arrangements of a buoyant gate have been explained above, p.
429.
[181] In the year 1856 and afterwards, Mr. Brunel was engaged in
improving the navigable channel of the river Neath, at its embouchure
into the Bristol Channel. A bank of furnace slag, for directing the
course of the river, had been made previously by Mr. Palmer, and
continued as far seawards as it was then thought could be done with
safety. Mr. Brunel carried a training bank still farther, and succeeded
in cutting off a bend of the river; Mr. Brereton has since extended the
navigable channel in a straight line to low-water mark, a distance of
two miles; and the bar has been lowered to within 1 foot of the level of
the dock sill.
[182] Reports on the Paris Universal Exhibition 1867 vol. i., p. xxiv.
194
[183] When, at the close of the Exhibition, Mr. Brunel was compelled,
much against his will, to accept a pecuniary acknowledgment of his
services, he spent the money in the erection of model cottages at
Barton, a village near his property in Devonshire.
[184] See Report of the Select Committee of the House of Commons on
Ordnance, 1863, Minutes of Evidence and Appendix (ordered to be printed
July 23, 1863):--p. 306, Report of Ordnance Select Committee; p. 44,
Statement of Mr. Whitworth; p. 56, Evidence of Mr. Whitworth (Q.
1329-1337); pp. 58, 59, the same (Q. 1385-1410); pp. 402, 403, Papers
delivered in by Mr. Isambard Brunel; p. 110, Further Evidence of Mr.
Whitworth (Q. 2545-2551); p. 112, the same (Q. 2602-2610); p. 548,
Letter from Mr. Westley Richards to Mr. Isambard Brunel.
[185] Captain Claxton, at Mr. Brunel’s desire, went for a voyage in
Messrs. Ruthven’s vessel, the ‘Enterprise,’ in order to test her
performances.
[186] This appears to be the only instance in which Mr. Brunel printed
an account of any of his works.
[187] On this application of tin for the covering of the roof, Dr.
Parkes observes (_Manual of Practical Hygiene_, London, 1869, p.
317):--‘In the Crimean War the roofs of Renkioi Hospital, on the
Dardanelles, were covered with polished tin; it was found, however,
somewhat difficult to place it so as to exclude rain, and the surface
soon became tarnished. The thermometric experiments did not show a
greater lessening of heat than 3° Fahr. below houses not tin-coated.’
[188] ‘At Renkioi, in Turkey, Mr. Brunel supplied square wooden sewers
about 15 inches to the side; they were tarred inside, and acted most
admirably without leakage for fifteen months, till the end of the war.
The water-closets (Jennings’s simple syphon), arranged with a small
water-box below the cistern, to economise water, never got out of order,
and in fact the drainage of the hospital was literally perfect. I have
little doubt such well-tarred wooden sewers would last two or three
years’ (Parkes’s _Manual of Practical Hygiene_, p. 635).
[189] The woodcut, fig. 22, is a reduction of part of this drawing.
[190] The case of Ranger _v._ the Great Western Railway Company.
[191] See above, p. 192.
[192] The remainder of this letter is printed above, p. 192.
[193] Although Mr. Brunel endeavoured, as far as possible, to lay aside
work during his visits to Watcombe, he found occasions for the use of
his mechanical knowledge. He prepared tools for transplanting young
trees; he did not, however, succeed in making them flourish as well as
before they were transplanted, though he attended to the work himself,
and took care that a large amount of earth was moved with the tree. The
bridge of rough poles across the turnpike road between Teignmouth and
Torquay is as good of its kind as his larger works.
[194] On June 10, 1830, when he was twenty-four years old, Mr. Brunel
was elected a Fellow of the Royal Society. He subsequently became a
member of most of the other scientific societies; but he rarely attended
any meetings, except those of the Institution of Civil Engineers.
[195] At the beginning of 1858, on the expiration of Mr. Robert
Stephenson’s term of office as President of the Institution of Civil
Engineers, Mr. Brunel came next in rotation for election; but his
failing health, and the pressure of his professional duties, led him to
request that he might not then be put in nomination.--- See Inaugural
Address of John Fowler, Esq., January 9, 1866.
[196] A drawing of their Nile boat, the ‘Florence,’ which he made for
his daughter, exhibits the same beautiful minuteness which appears in
all his early sketches for the Clifton bridge and Great Western Railway.
[197] Mr. Brunel’s Nile boat, being of iron, could not safely go up the
Cataracts.
[198] A few weeks after Mr. Brunel’s death, a meeting of his friends was
held, when it was determined to raise some memorial to him. A statue was
made by the late Baron Marochetti, and a site for it promised by the
First Commissioner of Works; but it has not yet been erected.
Mr. Brunel’s family, by the permission of the Dean of Westminster, have
placed a memorial window in the north aisle of the nave of Westminster
Abbey.
Along the bottom of the window (which consists of two lights, each 23
feet 6 inches high and 4 feet wide, surmounted by a quatrefoil opening,
6 feet 6 inches across) is the Inscription, ‘IN MEMORY OF ISAMBARD
KINGDOM BRUNEL, CIVIL ENGINEER. BORN APRIL 9, 1806. DEPARTED THIS LIFE,
SEPTEMBER 15, 1859.’ Over this are four allegorical figures (two in each
light): Fortitude, Justice, Faith, and Charity. The upper part of the
window consists of six panels, divided by a pattern work of lilies and
pomegranates. The panels contain subjects from the history of the
Temple. The three subjects in the western light represent scenes from
the Old Testament--viz. the Dedication of the Temple by Solomon, the
Finding of the Book of the Law by Hilkiah, and the Laying the
Foundations of the Second Temple. The subjects in the eastern light are
from the New Testament--viz. Simeon Blessing the Infant Saviour, Christ
Disputing with the Doctors, and The Disciples pointing out to Christ the
Buildings of the Temple. In the heads of each light are angels kneeling,
and in the quatrefoil is a representation of Our Lord in Glory,
surrounded by angels.
The work was placed in the hands of Mr. R. Norman Shaw, architect, who
prepared the general design, arranged the scale of the various figures,
and designed the ornamental pattern work. The figure subjects were drawn
by Mr. Henry Holiday, and the whole design was executed in glass by
Messrs. Heaton, Butler, & Bayne.
[199] Mr. Locke here spoke in feeling language of Mr. Robert Stephenson.
[200] There appears, from the table, to be an immense extent of
paddle-board to this vessel, if the table be correct--greater than the
midship section.
[201] In a Report by Mr. Brunel on improvements in the port of Bristol,
dated December 26, 1839, the following passage occurs: ‘A great change
is unquestionably about to take place in the carriage of merchandise by
sea, a change similar, though possibly not so striking, as that which
has so suddenly been effected by railways in land carriage. To ensure
the speed which the passenger traffic demands, great size in the vessels
is required; in the course of a very few years we shall find Atlantic
steamers desirous of taking 500 or 600 tons of cargo to make up their
draught.’
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