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Title: Scientific American Supplement, No. 620,  November 19,1887
Author: Various
Language: English
As this book started as an ASCII text book there are no pictures available.
Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

*** Start of this Doctrine Publishing Corporation Digital Book "Scientific American Supplement, No. 620,  November 19,1887" ***

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Scientific American Supplement. Vol. XXIV., No. 620.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

       *       *       *       *       *


I.    ARCHITECTURE--Bristol Cathedral--The history and description of
      this ancient building, with large illustration.--1 illustration. 9904

II.   BIOGRAPHY--Oliver Evans and the Steam Engine.--The work of this
      early pioneer, hitherto but slightly recognized at his true
      worth as an inventor.                                            9896

III.  CHEMISTRY--The Chemistry of the Cotton Fiber--By Dr. BOWMAN--An
      interesting investigation, showing the variation in composition
      in different cottons.                                            9909

      Synthesis of Styrolene.                                          9910

      Notes on Saccharin.                                              9910

      Alcohol and Turpentine.                                          9910

IV.   ENGINEERING--Auguste's Endless Stone Saw--A valuable improvement,
      introducing the principle of the band saw, and producing a
      horizontal cut--10 illustrations.                                9896

V.    ELECTRICITY.--A Current Meter--The Jehl & Rupp meter for
      electricity described--1 illustration.                           9903

      Mix & Genest's Microphone Telephone--The new telephone recently
      adopted by the imperial post office department of Germany--3
      illustrations.                                                   9902

      Storage Batteries for Electric Locomotion--By A. RECKENZAUN--A
      valuable paper on this subject, giving historical facts and
      working figures of expense, etc.                                 9903

      The Telemeter System--By R.F. UPTON--The system of Ö.L. Clarke,
      of New York, as described before the British Association--A
      valuable tribute to an American inventor--1 illustration.        9900

VI.   METALLURGY.--The Newbery-Vautin Chlorination Process--A new
      process of extracting gold from its ores, with details of the
      management of the process and apparatus--1 illustration.         9907

VII.  MISCELLANEOUS.--A Gigantic Load of Lumber--The largest barge
      load of lumber ever shipped--The barge Wahnapitæ and her
      appearance as loaded at Duluth--1 illustration.                  9907

      Apparatus for Exercising the Muscles--An appliance for use by
      invalids requiring to exercise atrophied limbs--1 illustration.  9908

      Practical Education.--A plea for the support of manual training
      schools.                                                         9906

      Waves--The subject of ocean waves fully treated--An interesting
     _resume_ of our present knowledge of this phenomenon of
      fluids.                                                          9906

VIII. NAVAL ENGINEERING--The New Spanish Armored Cruiser Reina
      Regente.--Illustration and full description of this recent
      addition to the Spanish navy.--1 illustration.                   9895

      The Spanish Torpedo Boat Azor--Illustration and note of speed,
      etc., of this new vessel--1 illustration.                        9895

IX.   OPHTHALMOLOGY--The Bull Optometer--An apparatus for testing
      the eyesight.--The invention of Dr George J. Bull.--3
      illustrations.                                                   9908

X.    SANITATION AND HYGIENE--The Sanitation of Towns--By J. GORDON,
      C.E.--A presidential address before the Leicester meeting of
      the Society of Municipal and Sanitary Engineers and Surveyors
      of England.                                                      9909

XI.   TECHNOLOGY--A New Monster Revolving Black Ash Furnace and the
      Work Done with It--By WATSON SMITH--The great furnace of the
      Widnes Alkali Company described, with results and features of
      its working--4 illustrations.                                    9900

      Apparatus Used for Making Alcohol for Hospital Use during the
      Civil War between the States--By CHARLES K. GALLAGHER--A curiosity
      of war times described and illustrated.--1 illustration.         9900

      Confederate Apparatus for Manufacturing Saltpeter for Ammunition
      --By CHARLES K. GALLAGHER--Primitive process for extracting
      saltpeter from earth and other material--1 illustration.         9900

      Electrolysis and Refining of Sugar--A method of bleaching sugar
      said to be due to ozone produced by electric currents acting on
      the solution--1 illustration.                                    9903

      Improvements in the Manufacture of Portland Cement--By FREDERICK
      RANSOME, A.I.C.E.--An important paper recently read before the
      British Association, giving the last and most advanced methods
      of manufacture.                                                  9901

      Roburite, the New Explosive--Practical tests of this substance,
      with special application to coal mining.                         9897

      The Mechanical Reeling of Silk.--An advanced method of treating
      silk cocoons, designed to dispense with the old hand winding of
      the raw silk.--3 illustrations.                                  9898

       *       *       *       *       *



The Azor was built by Yarrow & Co., London, is of the larger class,
having a displacement of 120 tons, and is one of the fastest boats
afloat. Her speed is 24½ miles per hour. She has two tubes for
launching torpedoes and three rapid firing Nordenfelt guns. She lately
arrived in Santander, Spain, after the very rapid passage of forty
hours from England.

       *       *       *       *       *



The new armored cruiser Reina Regente, which has been built and
engined by Messrs. James & George Thomson, of Clydebank, for the
Spanish government, has recently completed her official speed trials
on the Clyde, the results attained being sufficient to justify the
statement made on her behalf that she is the fastest war cruiser in
the world. She is a vessel of considerable size, the following being
her measurements: Length over all, 330 ft., and 307 ft. between
perpendiculars; breadth, 50½ ft.; and her draught is 20 ft., giving a
displacement of 5,000 tons, which will be increased to 5,600 tons when
she is fully equipped.

This vessel belongs to the internally protected type of war cruisers,
a type of recent origin, and of which she is the largest example yet
built. The internal protection includes an armored deck which consists
of steel plates ranging from 3-1/8 in. in thickness in the flat center
to 4¾ in. at the sloping sides of the deck. This protective deck
covers the "vitals" of the ship, the machinery, boilers, etc. Then
there is a very minute subdivision in the hull of the ship, there
being, in all, 156 water-tight compartments, 83 of which are between
the armored deck and the one immediately above it, or between wind and
water. Most of these compartments are used as coal bunkers. Of the
remainder of the water-tight compartments, 60 are beneath the armor.
Throughout her whole length the Reina Regente has a double bottom,
which also extends from side to side of the ship. In order to keep the
vessel as free of water as possible, there have been fitted on board
four 14 in. centrifugal pumps, all of which are connected to a main
pipe running right fore and aft in the ship, and into which branches
are received from every compartment. These pumps are of the "Bon
Accord" type, and were supplied by Messrs. Drysdale & Co., Glasgow.

Not being weighted by massive external armor, the Reina Regente is
unusually light in proportion to her bulk, and in consequence it has
been rendered possible to supply her with engines of extraordinary
power. They are of the horizontal triple expansion type, driving twin
screws, and placed in separate water-tight compartments. The boilers,
four in number, are also in separate compartments. Well above the
water line there are two auxiliary boilers, which were supplied by
Messrs. Merryweather, London, and are intended for raising steam
rapidly in cases of emergency. These boilers are connected with all
the auxiliary engines of the ship, numbering no fewer than

The engines have been designed to indicate 12,000 horse power, and on
the trial, when they were making 110 revolutions per minute, they
indicated considerably upward of 11,000 horse power, the bearings all
the while keeping wonderfully cool, and the temperature of the engine
and boiler rooms being never excessive. The boilers are fitted with a
forced draught arrangement giving a pressure of 1 in. of water. In the
official run she attained a speed equal to 21 knots (over 24 miles)
per hour, and over a period of four hours an average speed of 20.72
knots per hour was developed, without the full power of the engines
being attained. The average steam pressure in the boilers was 140 lb.
per square inch. In the course of some private trials made by the
builders, the consumption of coal was tested, with the result that
while the vessel was going at a moderate speed the very low
consumption of 14 lb. of coal per indicated horse power per hour was
reached. The vessel is capable of steaming 6,000 knots when there is a
normal supply of coal in her bunkers, and when they are full there is
sufficient to enable her to steam 13,000 knots.

The Reina Regente will be manned by 50 officers and a crew of 350 men,
all of whom will have their quarters on the main deck. Among her
fittings and equipment there are three steam lifeboats and eight other
boats, five of Sir William Thomson's patent compasses, and a complete
electric light installation, the latter including two powerful search
lights, which are placed on the bridge. All parts of the vessel are in
communication by means of speaking tubes. In order to enable the
vessel to turn speedily, she is fitted with the sternway rudder of
Messrs. Thomson & Biles. This contrivance is a combination of a
partially balanced rudder with a rudder formed as a continuation of
the after lines of a ship. The partial balance tends to reduce the
strains on the steering gear, and thereby enables the rudder area to
be increased without unduly straining the gear.

When fitted out for actual service, this novel war cruiser will have a
most formidable armament, consisting of four 24 centimeter Hontorio
guns (each of 21 tons), six 12 centimeter guns (also of the Hontorio
type), six 6 pounder Nordenfelt guns, fourteen small guns, and five
torpedo tubes--one at the stern, two amidships, and two at the bow of
the ship.

It is worthy of note that this war cruiser was constructed in fifteen
months, or three months under the stipulated contract time; in fact,
the official trial of the vessel took place exactly eighteen months
from the signing of the contract. Not only is this the fastest war
cruiser afloat, but her owners also possess in the El Destructor what
is probably the simplest torpedo catcher afloat, a vessel which has
attained a speed of 22½ knots, or over 26 miles, per hour.

       *       *       *       *       *


A correspondent of the New York _Times_, deeming that far too much
credit has been given to foreigners for the practical development of
the steam engine, contributes the following interesting _resume_:

Of all the inventions of ancient or modern times none have more
importantly and beneficently influenced the affairs of mankind than
the double acting high pressure steam engine, the locomotive, the
steam railway system, and the steamboat, all of which inventions are
of American origin. The first three are directly and the last
indirectly associated with a patent that was granted by the State of
Maryland, in 1787, being the very year of the framing of the
Constitution of the United States. In view of the momentous nature of
the services which these four inventions have rendered to the material
and national interests of the people of the United States, it is to be
hoped that neither they nor their origin will be forgotten in the
coming celebration of the centennial of the framing of the

The high pressure steam engine in its stationary form is almost
ubiquitous in America. In all great iron and steel works, in all
factories, in all plants for lighting cities with electricity, in
brief, wherever in the United States great power in compact form is
wanted, there will be found the high pressure steam engine furnishing
all the power that is required, and more, too, if more is demanded,
because it appears to be equal to every human requisition. But go
beyond America. Go to Great Britain, and the American steam
engine--although it is not termed American in Great Britain--will be
found fast superseding the English engine--in other words, James
Watt's condensing engine. It is the same the world over. On all the
earth there is not a steam locomotive that could turn a wheel but for
the fact that, in common with every locomotive from the earliest
introduction of that invention, it is simply the American steam engine
put on wheels, and it was first put on wheels by its American
inventor, Oliver Evans, being the same Oliver Evans to whom the State
of Maryland granted the before mentioned patent of 1787.

He is the same Oliver Evans whom Elijah Galloway, the British writer
on the steam engine, compared with James Watt as to the authorship of
the locomotive, or rather "steam carriage," as the locomotive was in
those days termed. After showing the unfitness of Mr. Watt's low
pressure steam engine for locomotive purposes, Mr. Galloway, more than
fifty years ago, wrote: "We have made these remarks in this place in
order to set at rest the title of Mr. Watt to the invention of steam
carriages. And, taking for our rule that the party who first attempted
them in practice by mechanical arrangements of his own is entitled to
the reputation of being their inventor, Mr. Oliver Evans, of America,
appears to us to be the person to whom that honor is due." He is the
same Oliver Evans whom the _Mechanics' Magazine_, of London, the
leading journal of its kind at that period, had in mind when, in its
number of September, 1830, it published the official report of the
competitive trial between the steam carriages Rocket, San Pariel,
Novelty, and others on the Liverpool and Manchester Railway.

In that trial the company's engines developed about 15 miles in an
hour, and spurts of still higher speed. The _Magazine_ points to the
results of the trial, and then, under the heading of "The First
Projector of Steam Traveling," it declares that all that had been
accomplished had been anticipated and its feasibility practically
exemplified over a quarter of a century before by Oliver Evans, an
American citizen. The _Magazine_ showed that many years before the
trial Mr. Evans had offered to furnish steam carriages that, on level
railways, should run at the rate of 300 miles in a day, or he would
not ask pay therefor. The writer will state that this offer by Mr.
Evans was made in November, 1812, at which date not a British steam
carriage had yet accomplished seven miles in an hour.

In 1809 Mr. Evans endeavored to establish a steam railway both for
freight and passenger traffic between New York and Philadelphia,
offering to invest $500 per mile in the enterprise. At the date of his
effort there was not a railway in the world over ten miles long, nor
does there appear to have been another human being who up to that date
had entertained even the thought of a steam railway for passenger and
freight traffic. In view of all this, is it at all surprising that the
British _Mechanics' Magazine_ declared Oliver Evans, an American, to
be the first projector of steam railway traveling? In 1804 Mr. Evans
made a most noteworthy demonstration, his object being to practically
exemplify that locomotion could be imparted by his high pressure steam
engine to both carriages and boats, and the reader will see that the
date of the demonstration was three years before Fulton moved a boat
by means of Watt's low pressure steam engine. The machine used
involved the original double acting high pressure steam engine, the
original steam locomotive, and the original high pressure steamboat.
The whole mass weighed over twenty tons.

Notwithstanding there was no railway, except a temporary one laid over
a slough in the path, Mr. Evans' engine moved this great weight with
ease from the southeast corner of Ninth and Market streets, in the
city of Philadelphia, one and a half miles, to the River Schuylkill.
There the machine was launched into the river, and the land wheels
being taken off and a paddle wheel attached to the stern and connected
with the engine, the now steamboat sped away down the river until it
emptied into the Delaware, whence it turned upward until it reached
Philadelphia. Although this strange craft was square both at bow and
stern, it nevertheless passed all the up-bound ships and other sailing
vessels in the river, the wind being to them ahead. The writer repeats
that this thorough demonstration by Oliver Evans of the possibility of
navigation by steam was made three years before Fulton. But for more
than a quarter of a century prior to this demonstration Mr. Evans had
time and again asserted that vessels could be thus navigated. He did
not contend with John Fitch, but on the contrary tried to aid him and
advised him to use other means than oars to propel his boat. But Fitch
was wedded to his own methods. In 1805 Mr. Evans published a book on
the steam engine, mainly devoted to his form thereof. In this book he
gives directions how to propel boats by means of his engine against
the current of the Mississippi. Prior to this publication he
associated himself with some citizens of Kentucky--one of whom was the
grandfather of the present Gen. Chauncey McKeever, United States
Army--the purpose being to build a steamboat to run on the
Mississippi. The boat was actually built in Kentucky and floated to
New Orleans. The engine was actually built in Philadelphia by Mr.
Evans and sent to New Orleans, but before the engine arrived out the
boat was destroyed by fire or hurricane. The engine was then put to
sawing timber, and it operated so successfully that Mr. Stackhouse,
the engineer who went out with it, reported on his return from the
South that for the 13 months prior to his leaving the engine had been
constantly at work, not having lost a single day!

The reader can thus see the high stage of efficiency which Oliver
Evans had imparted to his engine full 80 years ago. On this point Dr.
Ernst Alban, the German writer on the steam engine, when speaking of
the high pressure steam engine, writes: "Indeed, to such perfection
did he [Evans] bring it, that Trevithick and Vivian, who came after
him, followed but clumsily in his wake, and do not deserve the title
of either inventors or improvers of the high pressure engine, which
the English are so anxious to award to them.... When it is considered
under what unfavorable circumstances Oliver Evans worked, his merit
must be much enhanced; and all attempts made to lessen his fame only
show that he is neither understood nor equaled by his detractors."

The writer has already shown that there are bright exceptions to this
general charge brought by Dr. Alban against British writers, but the
overwhelming mass of them have acted more like envious children than
like men when speaking of the authorship of the double acting high
pressure steam engine, the locomotive, and the steam railway system.
Speaking of this class of British writers, Prof. Renwick, when
alluding to their treatment of Oliver Evans, writes: "Conflicting
national pride comes in aid of individual jealousy, and the writers of
one nation often claim for their own vain and inefficient projectors
the honors due to the successful enterprise of a foreigner." Many of
these writers totally ignore the very existence of Oliver Evans, and
all of them attribute to Trevithick and Vivian the authorship of the
high pressure steam engine and the locomotive. Yet, when doing so, all
of them substantially acknowledge the American origin of both
inventions, because it is morally certain that Trevithick and Vivian
got possession of the plans and specifications of his engine. Oliver
Evans sent them to England in 1794-5 by Mr. Joseph Stacy Sampson, of
Boston, with the hope that some British engineer would approve and
conjointly with him take out patents for the inventions. Mr. Sampson
died in England, but not until after he had extensively exhibited Mr.
Evans' plans, apparently, however, without success. After Mr.
Sampson's death Trevithick and Vivian took out a patent for a high
pressure steam engine. This could happen and yet the invention be
original with them.

But they introduced into Cornwall a form of boiler hitherto unknown in
Great Britain, namely, the cylindrical flue boiler, which Oliver Evans
had invented and used in America years before the names of Trevithick
and Vivian were associated with the steam engine. Hence, they were
charged over fifty years ago with having stolen the invention of Mr.
Evans, and the charge has never been refuted. Hence when British
writers ignore the just claims of Oliver Evans and assert for
Trevithick and Vivian the authorship of the high pressure steam engine
and the locomotive, they thereby substantially acknowledge the
American origin of both inventions. They are not only of American
origin, but their author, although born in 1755, was nevertheless an
American of the second generation, seeing that he was descended from
the Rev. Dr. Evans Evans, who in the earlier days of the colony of
Pennsylvania came out to take charge of the affairs of the Episcopal
Church in Pennsylvania.

The writer has thus shown that with the patent granted by the State of
Maryland to Oliver Evans in 1787 were associated--first, the double
acting high pressure steam engine, which to-day is the standard steam
engine of the world; second, the locomotive, that is in worldwide use;
third, the steam railway system, which pervades the world; fourth, the
high pressure steamboat, which term embraces all the great ocean
steamships that are actuated by the compound steam engine, as well as
all the steamships on the Mississippi and its branches.

The time and opportunity has now arrived to assert before all the
world the American origin of these universally beneficent inventions.
Such a demonstration should be made, if only for the instruction of
the rising generation. Not a school book has fallen into the hands of
the writer that correctly sets forth the origin of the subject matter
of this paper. He apprehends that it is the same with the books used
in colleges and universities, for otherwise how could that parody on
the history of the locomotive, called "The Life of George Stephenson,
Railway Engineer," by Samuel Smiles, have met such unbounded success?
To the amazement of the writer, a learned professor in one of the most
important institutions of learning in the country did, in a lecture,
quote Smiles as authority on a point bearing on the history of the
locomotive! It is true that he made amends by adding, when his lecture
was published, a counter statement; but that such a man should have
seriously cited such a work shows the widespread mischief done among
people not versed in engineering lore by the admirably written romance
of Smiles, who as Edward C. Knight, in his Mechanical Dictionary,
truly declares, has "pettifogged the whole case." If, as Prof. Renwick
intimates, "conflicting national pride" has led the major part of
British writers to suppress the truth as to the origin of the high
pressure steam engine, the locomotive, and the steam railway system,
surely true national pride should induce the countrymen of Oliver
Evans to assert it. In closing this paper the writer will say, for the
information of the so-called "practical" men of the country, or, in
other words, those men whose judgment of an invention is mainly guided
by its money value, that Poor's Manual of Railroads in the United
States for 1886 puts their capital stock and their debts at over
$8,162,000,000. The value of the steamships and steamboats actuated by
the high pressure steam engine the writer has no means of
ascertaining. Neither can he appraise the factories and other plants
in the United States--to say nothing of the rest of the world--in
which the high pressure steam engine forms the motive power.

       *       *       *       *       *


It does not seem as if the band or endless saw should render the same
services in sawing stone as in working wood and metals, for the
reason that quite a great stress is necessary to cause the advance of
the stone (which is in most cases very heavy) against the blade. Mr.
A. Auguste, however, has not stopped at such a consideration, or,
better, he has got round the difficulty by holding the block
stationary and making the blade act horizontally. Fig. 1 gives a
general view of the apparatus; Fig. 2 gives a plan view; Fig. 3 is a
transverse section; Fig. 4 is an end view; Figs. 5, 6, and 7 show
details of the water and sand distributer; and Figs. 8, 9, and 10 show
the pulleys arranged for obtaining several slabs at once.

[Illustration: FIG. 1 AUGUSTE'S STONE SAW.]

[Illustration: FIG. 2 AUGUSTE'S STONE SAW.]

[Illustration: FIGS. 3 and 4 AUGUSTE'S STONE SAW.]

[Illustration: FIGS. 5 through 10 AUGUSTE'S STONE SAW.]

The machine is wholly of cast iron. The frame consists of four
columns, A, bolted to a rectangular bed plate, A', and connected above
by a frame, B, that forms a table for the support of the transmission
pieces, as well as the iron ladders, _a_, and the platform, _b_, that
supports the water reservoirs, C, and sand receptacles, C'.

Between the two columns at the ends of the machine there are two
crosspieces, D and D', so arranged that they can move vertically, like
carriages. These pieces carry the axles of the pulleys, P and P',
around which the band saw, S, passes. In the center of the bed plate,
A', which is cast in two pieces connected by bolts, there are ties to
which are screwed iron rails, _e_, which form a railway over which the
platform car, E, carrying the stone is made to advance beneath the

The saw consists of an endless band of steel, either smooth or
provided with teeth that are spaced according to the nature of the
material to be worked. It passes around the pulleys, P and P', which
are each encircled by a wide and stout band of rubber to cause the
blade to adhere, and which are likewise provided with two flanges. Of
the latter, the upper one is cast in a piece with the pulley, and the
lower one is formed of sections of a circle connected by screws. The
pulley, P, is fast, and carries along the saw; the other, P', is
loose, and its hub is provided with a bronze socket (Figs. 1 and 4).
It is through this second pulley that the blade is given the desired
tension, and to this effect its axle is forged with a small disk
adjusted in a frame and traversed by a screw, _d'_, which is
maneuvered through a hand wheel. The extremities of the crosspieces, D
and D', are provided with brass sockets through which the pieces slide
up and down the columns, with slight friction, under the action of the
vertical screws, _g_ and _g'_, within the columns.

A rotary motion is communicated to the four screws simultaneously by
the transmission arranged upon the frame. To this effect, the pulley,
P, which receives the motion and transmits it to the saw, has its
axle, _f_, prolonged, and grooved throughout its length in order that
it may always be carried along, whatever be the place it occupies, by
the hollow shaft, F, which is provided at the upper extremity with a
bevel wheel and two keys placed at the level of the bronze collars of
its support, G. The slider, D, is cast in a piece with the pillow
block that supports the shaft, _f_, and the bronze bushing of this
pillow block is arranged to receive a shoulder and an annular
projection, both forged with the shaft and designed to carry it, as
well as the pulley, P, keyed to its extremity. Now the latter, by its
weight, exerts a pressure which determines a sensible friction upon
the bushing through this shoulder and projection, and, in order to
diminish the same, the bushing is continuously moistened with a
solution of soap and water through the pipe, _g_, which runs from the
reservoir, G'.

The saw is kept from deviating from its course by movable guides
placed on the sliders, D and D'. These guides, H and H', each consist
of a cast iron box fixed by a nut to the extremity of the arms, _h_
and _h'_, and coupled by crosspieces, _j_ and _j'_, which keep them
apart and give the guides the necessary rigidity.

The shaft, _m_, mounted in pillow blocks fixed to the left extremity
of the frame, receives motion from the motor through the pulley, _p_,
at the side of which is mounted the loose pulley, _p_. This motion is
transmitted by the drum, M, and the pulley, L, to the shaft, _l_, at
the other extremity. This latter is provided with a pinion, _l'_,
which, through the wheel, F', gives motion to the saw. The shaft, _m_,
likewise controls the upward or downward motion of the saw through the
small drums, N and _n_, and the two pairs of fast and loose pulleys,
N' and _n'_. This shaft, too, transmits motion (a very slow one) to
the four screws, _g_ and _g'_, in the interior of the columns, and the
nuts of which are affixed to the sliders, D and D'. To this effect,
the shaft, _q_, is provided at its extremities with endless screws
that gear with two wheels, _q_', with helicoidal teeth fixed near the
middle of two parallel axes, _r_, running above the table, B, and
terminating in bevel wheels, _r'_, that engage with similar wheels
fixed at the end of the screws, _g_ and _g'_.

The car that carries the block to the saw consists of a strong frame,
E, mounted upon four wheels. This frame is provided with a pivot and a
circular track for the reception of the cast iron platform, E', which
rests thereon through the intermedium of rollers. Between the
rails, _e_, and parallel with them, are fixed two strong screws, _e'_,
held by supports that raise them to the bottom of the car frame, so
that they can be affixed thereto. When once the car is fastened in
this way, the screws are revolved by means of winches, and the block
is thus made to advance or recede a sufficient distance to make the
lines marked on its surface come exactly opposite the saw blade.

In sawing hard stones, it is necessary, as well known, to keep up a
flow of water and fine sand upon the blade in order to increase its
friction. Upon two platforms, _b_, at the extremities of the machine,
are fixed the water reservoir, C, and the receptacles, C', containing
fine sand or dry pulverized grit stone. As may be seen from Figs. 5
and 6, the bottom of the sand box, C', is conical and terminates in a
hopper, T, beneath which is adjusted a slide valve, _t_, connected
with a screw that carries a pulley, T'. By means of this valve, the
bottom of the hopper may be opened or closed in such a way as to
regulate the flow of the sand at will by acting upon the pulley, T',
through a chain, _t'_, passing over the guide pulley, _t²_. A rubber
tube, _u_, which starts from the hopper, runs into a metal pipe, U,
that descends to the guide, H, with which it is connected by a collar.
Under the latter, this pipe terminates in a sphere containing a small
aperture to allow the sand to escape upon an inclined board provided
with a flange. At the same time, through the rubber tube, _c_, coming
from the reservoir, C, a stream of water is directed upon the board in
order to wet the sand.

As the apparatus with but a single endless saw makes but two kerfs at
once, Mr. Auguste has devised an arrangement by means of which several
blades may be used, and the work thus be expedited.

Without changing the general arrangements, he replaces the pulleys, P
and P', by two half drums, V and V' (Figs. 8, 9, and 10), which are
each cast in a piece with the crosspieces, D² and D³, designed to
replace D and D', and, like them, sliding up and down the columns, A,
of the frame. Motion is transmitted to all the saw blades by a cog
wheel, X, keyed to the vertical shaft, _f_, and gearing with small
pinions, _x_, which are equally distant all around, and which
themselves gear with similar pinions forming the radii of a succession
of circles concentric with the first. All these pinions are mounted
upon axles traversing bronze bearings within the drum, which, to this
effect, is provided with slots. The axles of the pinions are prolonged
in order to receive rollers, _x'_, surrounded with rubber so as to
facilitate, through friction, the motion of all the blades running
between them.

The other drum, V', is arranged in the same way, except that it is not
cast in a piece with the carriage, D³, but is so adjusted to it that
a tension may be exerted upon the blades by means of the screw, _d_,
and its hand wheel.

Through this combination, all the blades are carried along at once in
opposite directions and at the same speed.--_Publication

       *       *       *       *       *


A series of experiments of great interest and vital importance to
colliery owners and all those engaged in mining coal has been carried
out during the last ten days in the South Yorkshire coal field. The
new mines regulation act provides that any explosible used in coal
mines shall either be fired in a water cartridge or be of such a
nature that it cannot inflame firedamp. This indeed is the problem
which has puzzled many able chemists during the last few years, and
which Dr. Roth, of Berlin, claims to have solved with his explosive
"roburite." We recently gave a detailed account of trials carried out
at the School of Military Engineering, Chatham, to test the safety and
strength of roburite, as compared with gun cotton, dynamite, and
blasting gelatine. The results were conclusive of the great power of
the new explosive, and so far fully confirmed the reports of the able
mining engineer and the chemical experts who had been sent to Germany
to make full inquiries. These gentlemen had ample opportunity of
seeing roburite used in the coal mines of Westphalia, and it was
mainly upon their testimony that the patents for the British empire
were acquired by the Roburite Explosive Company.

It has, however, been deemed advisable to give practical proof to
those who would have to use it, that roburite possesses all the high
qualities claimed for it, and hence separate and independent trials
have been arranged in such representative collieries as the
Wharncliffe Silkstone, near Sheffield, Monk Bretton, near Barnsley,
and, further north, in the Durham coal field, at Lord Londonderry's
Seaham and Silksworth collieries. Mr. G.B. Walker, resident manager of
the Wharncliffe Colliery Company, had gone to Germany as an
independent observer--provided with a letter of introduction from the
Under Secretary of State for Foreign Affairs--and had seen the
director of the government mines at Saarbruck, who gave it as his
opinion that, so far as his experience had gone, the new explosive was
a most valuable invention. Mr. Walker was so impressed with the great
advantages of roburite that he desired to introduce it into his own
colliery, where he gladly arranged with the company to make the first
coal mining experiments in this country. These were recently carried
out in the Parkgate seam of the Wharncliffe Silkstone colliery, under
the personal superintendence of the inventor, Dr. Roth, and in the
presence of a number of colliery managers and other practical men.

In all six shots were fired, five of which were for the purpose of
winning coal, while the sixth was expressly arranged as a "blowout
shot." The roburite--which resembles nothing so much as a common
yellow sugar--is packed in cartridges of about 4½ in. in length and 1½
in. in diameter, each containing about 65 grammes (one-seventh of a
pound) inclosed in a waterproof envelope. By dividing a cartridge, any
desired strength of charge can be obtained. The first shot had a
charge of 90 grammes (one-fifth of a pound) placed in a hole drilled
to a depth of about 4 ft. 6 in., and 1¾ in. in diameter. All the
safety lamps were carefully covered, so that complete darkness was
produced, but there was no visible sign of an explosion in the shape
of flame--not even a spark--only the dull, heavy report and the noise
made by the displaced coal. A large quantity of coal was brought
down, but it was considered by most of the practical men present to be
rather too much broken. The second shot was fired with a single
cartridge of 65 grammes, and this gave the same remarkable results as
regards absence of flame, and, in each case, there were no noxious
fumes perceivable, even the moment after the shot was fired. This
reduced charge gave excellent results as regards coal winning, and one
of the subsequent shots, with the same weight of roburite, produced
from 10 to 11 tons of coal in almost a solid mass.

It has been found that a fertile cause of accidents in coal mines is
insufficient tamping, or "stemming," as it is called in Yorkshire.
Therefore a hole was bored into a strong wall of coal, and a charge of
45 grammes inserted, and very slightly tamped, with the view of
producing a flame if such were possible. This "blowout" shot is so
termed from the fact of its being easier for the explosion to blow out
the tamping, like the shot from a gun, than to split or displace the
coal. The result was most successful, as there was no flash to relieve
the utter darkness.

The second set of experiments took place on October 24 last, in the
Monk Bretton colliery, near Barnsley, of which Mr. W. Pepper, of
Leeds, is owner. This gentleman determined to give the new explosive a
fair and exhaustive trial, and the following programme was carried out
in the presence of a very large gathering of gentlemen interested in
coal mining. The chief inspector of mines for Yorkshire and
Lincolnshire, Mr. F.N. Wardell, was also present, and the Roburite
Explosives Company was represented by Lieut.-General Sir John Stokes,
K.C.B., R.E., chairman, and several of the directors.

1. _Surface Experiments._--A shot fired on the ground, exposed. This
gave no perceptible flame (70 grammes of roburite was the charge in
these experiments).

2. A shot fired on the ground, bedded in fine coal dust. No flame nor
ignition of the coal dust was perceptible.

3. A shot fired suspended in a case into which gas was conducted, and
the atmospheric air allowed to enter so as to form an explosive
mixture. The gas was not fired.

4. A shot fired in a boiler flue 16 ft. by 2 ft. 8 in., placed
horizontally, in which was a quantity of fine coal dust kept suspended
in the air by the action of a fan. No flame nor ignition of the coal
dust took place.

5. A shot fired as above, except that an explosive mixture of gas and
air was flowing into the boiler tube in addition to the coal dust.
That this mixture was firedamp was proved by the introduction of a
safety lamp, the flame of which was elongated, showing what miners
call the "blue cap." There was no explosion of the gas or sign of

6. A shot of roburite fired in the boiler tube without any gas or
suspended coal dust. The report was quite as loud as in the preceding
case; indeed, to several present it seemed more distinct.

7. A shot of ½ lb. gunpowder was fired under the same condition as No.
5, i.e., in an explosive mixture of gas and air with coal dust. The
result was most striking, and appeared to carry conviction of the
great comparative safety of roburite to all present. Not only was
there an unmistakable explosion of the firedamp, with very loud
report, and a vivid sheet of flame, but the gas flowing into the far
end of the boiler tube was ignited and remained burning until turned

_In the Pit._--1. A 2 in. hole was drilled 4 ft. 6 in. deep into coal,
having a face 7 yards wide, fast at both ends, and holed under for a
depth of 8 ft., end on, thickness of front of coal to be blown down 2
ft. 10 in., plus 9 in. of dirt. This represented a most difficult
shot, having regard to the natural lines of cleavage of the coal--a
"heavy job" as it was locally termed. The charge was 65 grammes of
roburite, which brought down a large quantity of coal, not at all too
small in size. No flame was perceptible, although all the lamps were
carefully covered.

2. A 2 in. hole drilled 4 ft. 6 in. into the side of the coal about 10
in. from the top, fast ends not holed under, width of space 10 ft.
This was purposely a "blowout" shot. The result was again most
satisfactory, the charge exploding in perfect darkness.

3. A "breaking up" shot placed in the stone roof for "ripping," the
hole being drilled at an angle of 35 deg. or 40 deg. This is intended
to open a cavity in the perfectly smooth roof, the ripping being
continued by means of the "lip" thus formed. The charge was 105
grammes (nearly 4 oz), and it brought down large quantities of stone.

4. A "ripping" shot in the stone roof, hole 4 ft. 6 in. deep, width of
place 15 ft. with a "lip" of 2 ft. 6 in. This is a strong stone
"bind," and very difficult to get down. The trial was most successful,
a large heap of stone being brought down and more loosened.

5. A second "blowout" shot, under the conditions most likely to
produce an accident in a fiery mine. A 2 in. hole, 4 ft. 6 in. deep,
was drilled in the face of the coal near the roof, and charged with
105 grammes of roburite. A space of 6 in. or 8 in. was purposely left
between the charge and the tamping. The hole was then strongly tamped
for a distance of nearly 2 ft. The report was very loud, and a
trumpet-shaped orifice was formed at the mouth of the hole, but no
flame or spark could be perceived, nor was any inconvenience caused by
the fumes, even the instant after the explosion.

_Further Experiments at Wharncliffe Colliery._--On Tuesday, October
25, some very interesting surface trials were arranged with great care
by Mr. Walker. An old boiler flue was placed vertically, and closed at
top by means of a removable wooden cover, the interior space being
about 72 cubic feet. A temporary gasometer had been arranged at a
suitable distance by means of a paraffin cask having a capacity of 6
cubic feet suspended inside a larger cask, and by this means the
boiler was charged with a highly explosive mixture of gas and air in
the proportion of 1 to 12.

1. A charge of gunpowder was placed in the closed end of a piece of
gas pipe, and strongly tamped, so as to give the conditions most
unfavorable to the ignition of the firedamp. It was, however, ignited,
and a loud explosion produced, which blew off the wooden cover and
filled the boiler tube with flame.

2. Under the same conditions as to firedamp, a charge of roburite was
placed on a block of wood inside the boiler, totally unconfined except
by a thin covering of coal dust. When exploded by electricity, as in
the previous case, no flame was produced, nor was the firedamp

3. The preceding experiment was repeated with the same results.

4. A charge of blasting gelatine, inserted in one of Settle's water
cartridges, was suspended in the boiler tube and fired with a
fulminate of mercury detonator in the usual manner. The gelatine did
not, however, explode, the only report being that of the detonator.
After a safe interval the unexploded cartridge was recovered, or so
much of it as had not been scattered by the detonator, and the
gelatine was found to be frozen. This fact was also evident from an
inspection of other gelatine dynamite cartridges which had been stored
in the same magazine during the night. This result, although not that
intended, was most instructive as regards the danger of using
explosives which are liable to freeze at such a moderate temperature,
and the thawing of which is undoubtedly attended with great risk
unless most carefully performed. Also, the small pieces of the
gelatine or dynamite, when scattered by the explosion of the
detonator, might cause serious accident if trodden upon.--_Engineering._

       *       *       *       *       *


When automatic machinery for thread spinning was invented, English
intelligence and enterprise were quick to utilize and develop it, and
thus gained that supremacy in textile manufacture which has remained
up to the present time, and which will doubtless long continue. The
making of the primary thread is the foundation of all textile
processes, and it is on the possibility of doing this by automatic
machinery that England's great textile industries depend. The use of
highly developed machinery for spinning cotton, wool, and flax has
grown to be so much a part of our conception of modern life, as
contrasted with the times of our grandfathers, as often to lead to the
feeling that a complete and universal change has occurred in all the
textile industries. This is, however, not the case. There is one great
textile industry--one of the most staple and valuable--still in the
primitive condition of former times, and employing processes and
apparatus essentially the same as those known and employed before such
development had taken place. We mean the art of silk reeling. The
improvements made in the production of threads of all other materials
have only been applied to silk in the minor processes for utilizing
waste; but the whole silk trade and manufacture of the world has, up
to this time, been dependent for its raw silk threads upon apparatus
which, mechanically speaking, is nearly or quite as primitive as the
ancient spinning wheels. Thousands of operatives are constantly
employed in forming up these threads by hand, adding filament by
filament to the thread as required, while watching the unwinding from
the cocoon of many miles of filament in order to produce a single
pound of the raw silk thread, making up the thread unaided by any
mechanical device beyond a simple reel on which the thread is wound as
finished, and a basin of heated water in which the cocoons are placed.

Viewed from any standpoint to which we are accustomed, this state of
things is so remarkable that we are naturally led to the belief that
there must be some special causes which tended to retard the
introduction of automatic machinery, and these are not far to seek.
The spinning machinery employed for the production of threads, other
than those of raw silk, may be broadly described as consisting of
devices capable of taking a mass of confused and comparatively short
fibers, laying them parallel with one another, and twisting them into
a cylindrical thread, depending for its strength upon the friction and
interlocking of these constituent fibers.

This process is radically different from that employed to make a
thread of raw silk, which consists of filaments, each several thousand
feet long, laid side by side, almost without twist, and glued together
into a solid thread by means of the "gum" or glue with which each
filament is naturally coated. If this radical difference be borne in
mind, but very little mechanical knowledge is required to make it
evident that the principle of spinning machinery in general is utterly
unsuited to the making up of the threads of raw silk. Since spinning
machinery, as usually constructed for other fibers, could not be
employed in the manufacture of raw silk, and as the countries where
silk is produced are, generally speaking, not the seat of great
mechanical industries, where the need of special machinery would be
quickly recognized and supplied, silk reeling (the making of raw silk)
has been passed by, and has never become an industrial art. It
remained one of the few manual handicrafts, while yet serving as the
base of a great and staple industry of worldwide importance.

There is every reason to suppose that we are about to witness a
transformation in the art of silk reeling, a change similar to that
which has already been brought about in the spinning of other threads,
and of which the consequences will be of the highest importance. For
some years past work has been done in France in developing an
automatic silk-reeling machine, and incomplete notes concerning it
have from time to time been published. That the accounts which were
allowed to reach the outer world were incomplete will cause no
surprise to those who know what experimental work is--how easily and
often an inventor or pioneer finds himself hampered by premature
publication. The process in question has now, however, emerged from
the experimental state, and is practically complete. By the courtesy
of the inventor we are in a position to lay before our readers an
exact analysis of the principles, essential parts, and method of
operation of the new silk-reeling machine. As silk reeling is not
widely known in England, it will, however, be well to preface our
remarks by some details concerning the cocoon and the manner in which
it is at present manufactured into raw silk, promising that if these
seem tedious, the labor of reading them will be amply repaid by the
clearer understanding of the new mechanical process which will be the

The silkworm, when ready to make its cocoon, seeks a suitable support.
This is usually found among the twigs of brush placed for the purpose
over the trays in which the worms have been grown. At first the worm
proceeds by stretching filaments backward and forward from one twig to
another in such manner as to include a space large enough for the
future cocoon. When sufficient support has thus been obtained, the
worm incloses itself in a layer of filaments adhering to the support
and following the shape of the new cocoon, of which it forms the
outermost stratum. After having thus provided a support and outlined
the cocoon, the worm begins the serious work of constrution. The
filament from its silk receiver issues from two small spinnarets
situated near its jaws. Each filament, as it comes out, is coated with
a layer of exceedingly tenacious natural gum, and they at once unite
to form a single flattened thread, the two parts lying side by side.
It is this flat thread, called the "baye" or "brin," which serves as
the material for making the cocoon, and which, when subsequently
unwound, is the filament used in making up the raw silk. While
spinning, the worm moves its head continually from right to left,
laying on the filament in a succession of lines somewhat resembling
the shape of the figure eight. As the worm continues the work of
making its cocoon, the filament expressed from its body in the manner
described is deposited in nearly even layers all over the interior of
the wall of the cocoon, which gradually becomes thicker and harder.
The filament issuing from the spinnarets is immediately attached to
that already in place by means of the gum which has been mentioned.
When the store of silk in the body of the worm is exhausted, the
cocoon is finished, and the worm, once more shedding its skin, becomes
dormant and begins to undergo its change into a moth. It is at this
point that its labors in the production of silk terminate and those of
man begin. A certain number of the cocoons are set aside for

In southern countries the reproduction of silkworms is a vast industry
to which great attention is given, and which receives important and
regular aid from the government. It is, however, quite distinct from
the manufacturing industry with which at present we have to do. The
cocoons to be used for reeling, i.e., all but those which are
reserved for reproduction, are in the first place "stifled," that is
to say, they are put into a steam or other oven and the insect is
killed. The cocoons are then ready for reeling, but those not to be
used at once are allowed to dry. In this process, which is carried on
for about two months, they lose about two-thirds of their weight,
representing the water in the fresh chrysalis. The standard and dried
cocoons form the raw material of the reeling mills, or filatures, as
they are called on the Continent. Each filature endeavors as far as
possible to collect, stifle, and dry the cocoons in its own
neighborhood; but dried cocoons, nevertheless, give rise to an
important commerce, having its center at Marseilles. The appearance of
the cocoon is probably well known to most of our readers. Industrially
considered, the cocoon may be divided into three parts: (1) The floss,
which consists of the remains of the filaments used for supporting the
cocoon on the twigs of the brush among which it was built and the
outside layer of the cocoon, together with such ends and parts of the
thread forming the main part of the shell as have become broken in
detaching and handling the cocoon; (2) the shell of the cocoon, which
is formed, as has been described, of a long continuous filament, which
it is the object of the reeler to unwind and to form up into threads
of raw silk; and (3) the dried body of the chrysalis.

We shall first describe the usual practice of reeling, which is as
follows: The cocoons are put into a basin of boiling water, on the
surface of which they float. They are stirred about so as to be as
uniformly acted upon as possible. The hot water softens the gum, and
allows the floss to become partially detached. This process is called
"cooking" the cocoons. When the cocoons are sufficiently cooked, they
are subjected to a process called "beating," or brushing, the object
of which is to remove the floss.

As heretofore carried on, this brushing is a most rudimentary and
wasteful operation. It consists of passing a brush of heather or broom
twigs over the floating cocoons in such manner that the ends of the
brush come in contact with the softened cocoons, catch the floss, and
drag it off. In practice it happens that the brush catches the sound
filaments on the surface of the cocoon as well as the floss, and, as a
consequence, the sound filament is broken, dragged off, and wasted. In
treating some kinds of cocoons as much as a third of the silk is
wasted in this manner, and even in the best reeling, as at present
practiced, there is an excessive loss from this cause. At the present
low price of cocoons this waste is not as important as it was some
time ago, when cocoons were much dearer; but even at present it
amounts to between fifteen and twenty millions of francs per annum in
the silk districts of France and Italy alone. In France the cooking
and brushing are usually done by the same women who reel, and in the
same basins. In Italy the brushing is usually done by girls, and often
with the aid of mechanically rotated brushes, an apparatus which is of
doubtful utility, as, in imitating the movement of hand brushing, the
same waste is occasioned.

After the cocoons are brushed they are, in the ordinary process,
cleaned by hand, which is another tedious and wasteful operation
performed by the reeler, and concerning which we shall have more to
say further on. Whatever may be the preparatory operations, they
result in furnishing the reeler with a quantity of cocoons, each
having its floss removed, and the end of the filament ready to be
unwound. Each reeler is provided with a basin containing water, which
may be heated either by a furnace or by steam, and a reel, upon which
the silk is wound when put in motion by hand or by power. In civilized
countries heating by steam and the use of motive power is nearly
universal. The reeler is ordinarily seated before the reel and the
basin. The reeler begins operations by assembling the cocoons in the
basin, and attaching all the ends to a peg at its side. She then
introduces the ends of the filaments from several cocoons into small
dies of agate or porcelain, which are held over the basin by a

The ends so brought in contact stick together, owing to the adhesive
substance they naturally contain, and form a thread. To wring out the
water which is brought up with the ends, and further consolidate the
thread, it is so arranged as to twist round either itself or another
similar thread during its passage from the basin to the reel. This
process is called "croisure," and is facilitated by guides or small
pulleys. Having made the croisure, which consists of about two hundred
turns, the operator attaches the end of a thread to the reel,
previously passing it through a guide fixed in a bar, which moves
backward and forward, so as to distribute the thread on the reel,
forming a hank about three inches wide.

The reel is now put into movement, and winds the thread formed by the
union of the filaments. It is at this moment that the real
difficulties of the reeler begin. She has now to maintain the size and
regularity of the thread as nearly as possible by adding new filaments
at the proper moment. The operation of adding an end of a filament
consists of throwing it in a peculiar manner on the other filaments
already being reeled, so that it sticks to them, and is carried up
with them. We may mention here that this process of silk reeling can
be seen in operation at the Manchester exhibition.

It is only after a long apprenticeship that a reeler succeeds in
throwing the end properly. The thread produced by the several
filaments is itself so fine that its size cannot readily be judged by
the eye, and the speed with which it is being wound renders this even
more difficult. But, in order to have an idea of the size, the reeler
watches the cocoons as they unwind, counts them, and, on the
hypothesis that the filament of one cocoon is of the same diameter as
that of another, gets an approximate idea of the size of the thread
that she is reeling. But this hypothesis is not exact, and the
filament being largest at the end which is first unwound, and tapering
throughout its whole length, the result is that the reeler has not
only to keep going a certain number of cocoons, but also to appreciate
how much has been unwound from each.

If the cocoons are but slightly unwound, there must be fewer than if a
certain quantity of silk has been unwound from them. Consequently
their number must be constantly varying in accordance with their
condition. These facts show that the difficulty of maintaining
regularity in a thread is very great. Nevertheless, this regularity is
one of the principal factors of the value of a thread of "grege," and
this to such an extent that badly reeled silks are sold at from twenty
to twenty-five francs a kilogramme less than those which are
satisfactorily regular.

The difficulty of this hand labor can be still better understood if it
be remembered that the reeler being obliged to watch at every moment
the unwinding of each cocoon, in order to obtain one pound of well
reeled silk, she must incessantly watch, and without a moment of
distraction, the unwinding of about two thousand seven hundred miles
of silk filaments. For nine pounds of silk, she reels a length of
filament sufficient to girdle the earth. The manufacturer, therefore,
cannot and must not depend only on the constant attention that each
reeler should give to the work confided to her care. He is obliged to
have overseers who constantly watch the reelers, so that the defects
in the work of any single reeler, who otherwise might not give the
attention required by her work, will not greatly diminish the value
either of her own work or that of several other reelers whose silk is
often combined to form a single lot. In addition to the ordinary hand
labor, considerable expense is thus necessitated for the watching of
the reelers.

Enough has now been said, we think, to give a good idea of silk
reeling, as usually practiced, and to show how much it is behind other
textile arts from a mechanical point of view. To any one at all
familiar with industrial work, or possessing the least power of
analysis or calculation, it is evident that a process carried on in
so primitive a manner is entirely unsuitable for use in any country in
which the conditions of labor are such as to demand its most
advantageous employment. In the United States, for instance, or in
England, silk reeling, as a great national industry, would be out of
the question unless more mechanical means for doing it could be
devised. The English climate is not suitable for the raising of
cocoons, and in consequence the matter has not attracted very much
attention in this country. But America is very differently situated.
Previous to 1876 it had been abundantly demonstrated that cocoons
could be raised to great advantage in many parts of that country. The
only question was whether they could be reeled. In fact, it was stated
at the time that the question of reeling silk presented a striking
analogy to the question of cotton before the invention of the "gin."
It will be remembered that cotton raising was several times tried in
the United States, and abandoned because the fiber could not be
profitably prepared for the market. The impossibility of competing
with India and other cheap labor countries in this work became at
least a fact fully demonstrated, and any hope that cotton would ever
be produced in America was confined to the breasts of a few

As soon, however, as it was shown that the machine invented by Eli
Whitney would make it possible to do this work mechanically, the
conditions were changed; cotton raising become not only possible, but
the staple industry of a great part of the country; the population was
rapidly increased, the value of real estate multiplied, and within a
comparatively short time the United States became the leading cotton
country of the world. For many years much more cotton has been grown
in America than in all the other countries of the world combined; and
it is interesting to note that both the immense agricultural wealth of
America and the supply required for the cotton industry of England
flow directly from the invention of the cotton gin.

Attention was turned in 1876 to silk raising, and it was found that
all the conditions for producing cocoons of good quality and at low
cost were most favorable. It was, however, useless to raise cocoons
unless they could be utilized; in a word, it was seen that the country
needed silk-reeling machinery in 1876, as it had needed cotton-ginning
machinery in 1790. Under these conditions, Mr. Edward W. Serrell, Jr.,
an engineer of New York, undertook the study of the matter, and soon
became convinced that the production of such machinery was feasible.
He devoted his time to this work, and by 1880 had pushed his
investigations as far as was possible in a country where silk reeling
was not commercially carried on. He then went to France, where he has
since been incessantly engaged in the heart of the silk-reeling
district in perfecting, reducing to practice, and applying his
improvements and inventions. The success obtained was such that Mr.
Serrell has been enabled to interest many of the principal silk
producers of the Continent in his work, and a revolution in silk
reeling is being gradually brought about, for, strangely enough, he
found that the work which he had undertaken solely for America was of
equal importance for all silk-producing countries.

We have described the processes by which cocoons are ordinarily cooked
and brushed, these being the first processes of the filature. Instead
of first softening the gum of the cocoons and then attacking the floss
with the points of a brush, Mr. Serrell places the cocoons in a
receptacle full of boiling water, in which by various means violent
reciprocating or vortex currents are produced. The result is that by
the action of the water itself and the rubbing of the cocoons one
against the other the floss is removed, carrying with it the end of
the continuous filament without unduly softening the cocoon or
exposing any of the more delicate filament to the rough action of the
brush, as has hitherto been the case. The advantages of this process
will be readily understood. In brushing after the ordinary manner, the
point of the brush is almost sure to come into contact with and to
break some of the filament forming the body of the cocoon. When this
occurs, and the cocoon is sent to be reeled, it naturally becomes
detached when the unwinding reaches the point at which the break
exists. It then has to be sent back, and the end of the filament
detached by brushing over again, when several layers of filament are
inevitably caught by the brush and wasted, and very probably some
other part of the filament is cut. This accounts for the enormous
waste which occurs in silk reeling, and to which we have referred. Its
importance will be appreciated when it is remembered that every pound
of fiber thus dragged off by the brush represents a net loss of about
19s. at the present low prices.

The mechanical details by which Mr. Serrell carries out this process
vary somewhat according to the nature of the different cocoons to be
treated. In one type of machine the water is caused to surge in and
out of a metal vessel with perforated sides; in another a vertical
brush is rapidly raised and lowered, agitating the water in a basin,
without, however, actually touching the cocoons. After a certain
number of strokes the brush is automatically raised, when the ends of
the filaments are found to adhere to it, having been swept against it
by the scouring action of the water. The cleaning of the cocoons is
performed by means of a mechanism also entirely new. In the brushing
machinery the floss is loosened and partially detached from the
cocoon. The object of the cleaning machine is to thoroughly complete
the operation. To this end the cocoons are floated under a plate, and
the floss passed up through a slot in the latter. A rapid to and fro
horizontal movement is given to the plate, and those cocoons from
which the floss has been entirely removed easily give off a few inches
of their filament, and allow themselves to be pushed on one side,
which is accomplished by the cocoons which still have some floss
adhering to them; because these latter, not being free to pay off, are
drawn up to the slot in the plate, and by its motion are rapidly
washed backward and forward in the water. This washing soon causes all
the cocoons to be freed from the last vestiges of floss without
breaking the filament, and after about twenty seconds of movement they
are all free and clean, ready for reeling.

We have now to explain the operation of the machine by which the
thread is formed from the prepared cocoon. At the risk of some
repetition, however, it seems necessary to call attention to the
character of the work itself. In each prepared cocoon are about a
thousand yards of filament ready to pay off, but this filament is
nearly as fine as a cobweb and is tapering. The object is to form a
thread by laying these filaments side by side in sufficient number to
obtain the desired size. For the threads of raw silk used in commerce,
the sizes vary, so that while some require but an average of three
filaments, the coarsest sizes require twenty-five or thirty. It being
necessary keep the thread at as near the same size as possible, the
work required is, in effect, to add an additional cocoon filament to
the thread which is being wound whenever this latter has tapered down
to a given size, or whenever one of the filaments going to form it has
become detached. Those familiar with cotton spinning will understand
what is meant when it is said that the reeling is effectively a
"doubling" operation, but performed with a variable number of ends, so
as to compensate for the taper of the filaments. In reeling by hand,
as has been said, the size of the silk is judged, as nearly as
possible, by a complex mental operation, taking into account the
number, size, and state of unwinding of the cocoons. It is impossible
to do this mechanically, if for no other reason than this, that the
cocoons must be left free to float and roll about in the water in
order to give off their ends without breaking, and any mechanical
device which touched them would defeat the object of the machine. The
only way in which the thread can be mechanically regulated in silk
reeling is by some kind of actual measurement performed after the
thread has left the cocoons. The conditions are such that no direct
measurement of size can be made, even with very delicate and expensive
apparatus; but Mr. Serrell discovered that, owing to the great
tenacity of the thread in proportion to its size, its almost absolute
elastic uniformity, and from the fact that it could be stretched, two
or three per cent. without injury, it was possible to measure its size
indirectly, but as accurately as could be desired. As this fact is the
starting point of an entirely new and important class of machinery, we
may explain with considerable detail the method in which this
measurement is performed. Bearing in mind that the thread is of
uniform quality, it is evident that it will require more force to
stretch a coarse thread by a given percentage of its length than it
will to stretch one that is finer. Supposing the thread is uniform in
quality but varying in size, the force required to stretch it varies
directly with the size or sectional area of the thread itself. In the
automatic reeling machine this stretch is obtained by causing the
thread to take a turn round a pulley of a given winding speed, and
then, after leaving this pulley, to take a turn around a second pulley
having a somewhat greater winding speed.


By this means the thread which is passing from one pulley to the other
is stretched by an amount equal to the difference of the winding speed
of the two pulleys. In the diagram (Fig. 2) the thread passes, as
shown by the arrows, over the pulley, P, and then over the pulley, P¹,
the latter having a slightly greater winding speed. Between these
pulleys it passes over the guide pulley, G. This latter is supported
by a lever hinged at S, and movable between the stops, TT¹. W is an
adjustable counterweight. When the thread is passed over the pulleys
and guided in this manner, the stretch to which it is subjected tends
to raise the guide and lever, so that the latter will be drawn up
against the stop, T¹, when the thread is so coarse that the effort
required to stretch it is sufficient to overcome the weight of the
guide pulley and the adjustable counterweight. But as the thread
becomes finer, which, in the case of reeling silk, happens either from
the tapering of the filaments or the dropping off of a cocoon, a
moment arrives when it is no longer strong enough to keep up the lever
and counterweight. These then descend, and the lever touches the lower
stop, T. It will be readily seen that the up and down movements of the
lever can be made to take place when the thread has reached any
desired maximum or minimum of size, the limits being fixed by suitably
adjusting the counterweight.

[Illustration: FIG. 2.]

In the automatic reeling machine this is the method employed for
regulating the supply of cocoons. The counterweight being suitably
adjusted, the lever falls when the thread has become fine enough to
need another cocoon. The stop, T, and the lever serve as two parts of
an electric contact, so that when they touch each other a circuit is
completed, which trips a trigger and sets in motion the feed apparatus
by which a new cocoon is added. In practice the two drums or pulleys
are mounted on the same shaft, D (Fig. 1), difference of winding speed
being obtained by making them of slightly different diameters.

The lever is mounted as a horizontal pendulum, and the less or greater
stress required according to the size to be reeled is obtained by
inclining its axis to a less or greater degree from the vertical. An
arrangement is also adopted by which the strains existing in the
thread when it arrives at the first drum are neutralized, so far as
their effect upon the lever is concerned. This is accomplished by
simply placing upon the lever an extra guide pulley, L¹, upon the side
opposite to that which corresponds to the guide shown in the diagram,
Fig. 2.

An electric contact is closed by a slight movement of the lever
whenever the thread requires a new filament of cocoon, and broken
again when the thread has been properly strengthened. It is evident
that a delicate faller movement might be employed to set the feed
mechanism in motion instead of the electric circuit, but, under the
circumstances, as the motion is very slight and without force, being,
in fact, comparable to the swinging of the beam of a balance through
the space of about the sixteenth of an inch, it is simpler to use a

The actual work of supplying the cocoons to the running thread is
performed as follows: The cleaned cocoons are put into what is called
the feeding basin, B1 (Fig. 1), a receptacle placed alongside of the
ordinary reeling basin, B, of a filature. A circular elevator, E, into
which the cocoons are charged by a slight current of water, lifts them
over one corner of the reeling basin and drops them one by one through
an aperture in a plate about six inches above the water of the reeling

The end of the filament having been attached to a peg above the
elevator, it happens that when a cocoon has been brought into the
corner of the reeling basin, the filament is strung from it to the
edge of the hole in the plate in such a position as to be readily
seized by a mechanical finger, K (Fig. 3), attached to a truck
arranged to run backward and forward along one side of the basin. This
finger is mounted on an axis, and has a tang projecting at right
angles to the side of the basin, so that the whole is in the form of a
bell crank mounted on the truck.

[Illustration: FIG. 3.]

There are usually four threads to each basin. When neither one of them
needs an additional cocoon, the finger of the distributing apparatus
remains, holding the filament of the cocoon at the corner of the basin
where it has been dropped. When a circuit is closed by the weakening
of any one of the threads, an electromagnetic catch is released, and
the truck with its finger is drawn across the basin by a weight. At
the same time the stop shown dotted in Fig. 3 is thrown out opposite
to the thread that needs strengthening. This stop strikes the tang of
the finger, and causes the latter to be thrown out near to the point
at which the filaments going to make up the weakened thread are being
drawn from the cocoons. Here the new filament is attached to the new
running thread by a kind of revolving finger, J, called in France a
"lance-bout." This contrivance takes the place of the agate of the
ordinary filature, and is made up, essentially, of the following

(1) A hollow axis, through the inside of which the thread passes
instead of going through the hole of an agate. This hollow axis is
furnished, near its lower end, with a ridge which serves to support a
movable portion turning constantly round the axis. (2) A movable
portion turning constantly round the axis. (3) A finger or hook
fastened on the side of the movable portion and revolving with it.
This hook, in revolving, catches the filament brought up by the finger
and serves it on to the thread.

Such are the principal parts of the automatic reeling machine.
Although the fact that this machine is entirely a new invention has
necessitated a somewhat long explanation, its principal organs can
nevertheless be summed up in a few words: (1) A controlling drum which
serves to give the thread a constant elongation; (2) a pulley mounted
on a pivot which closes an electric current every time that the thread
becomes too fine, and attains, in consequence, its minimum strength,
in other words, every time that a fresh cocoon is needed; (3)
electromagnets with the necessary conducting wires; (4) the feeding
basin; (5) distributing finger and stops; and (6) the lance-bout.

Our illustration, Fig. 1, shows diagrammatically a section through the
cocoon frame and reel. The thread is composed of three, four, or more
filaments, and after passing through the lance-bout, it travels as
shown by the arrows. At first it is wound round itself about two
hundred times, then passed over a fixed guide pulley, and over a
second guide pulley lower down fixed to the frames which carry the
lance-bouts, then up through the twist and over the smaller of the
pulleys, D. Taking one complete turn, it is led round the guide
pulley, L, from there round the larger of the pulleys, D, round the
second guide pulley, L¹, then back to the large wheel, and over a
fixed guide pulley across to the reeling frame. Power is supplied to
the latter by means of a friction clutch, and to insure even winding
the usual reciprocating motion of a guide is employed. The measuring
apparatus is pivoted at F, and by raising or lowering the nuts at the
end of the bar the required inclination is given.

We had recently an opportunity of examining the whole of this
machinery in detail, and seeing the process of silk reeling in actual
operation, Mr. Serrell having put up a complete set of his machines in
Queen Victoria Street, London. Regarded simply as a piece of ingenious
mechanism, the performance of these machines cannot fail to be of the
highest interest to engineers, the reeling machine proper seeming
almost endowed with human intelligence, so perfectly does it work.
But, apart from the technical perfection, Mr. Serrell's improvements
are of great importance as calculated to introduce the silk-reeling
industry in this country on a large scale, while at the same time its
effect upon India as a silk-growing country will be of equal

       *       *       *       *       *


  [Footnote 1: Read at the Cincinnati meeting of the American
  Pharmaceutical Association.]


A is an ordinary farm boiler or kettle, with an iron lid securely
bolted on; B, a steam pipe ending in a coil within a trough, D. C, D,
two troughs made of gum logs, one inverted over the other, securely
luted and fastened together by clamps and wedges. The "beer" to be
distilled was introduced at E and the opening closed with a plug. The
distillate--"low wine"--was collected at F, and redistilled from a set
of similar troughs not shown in above figure, and heated by a
continuation of the steam coil from D.


       *       *       *       *       *



Any convenient number of percolators, made of rough boards, arranged
over a trough after the style of the old fashioned "lye stand,"
similar to the figure. Into these was placed the earth scraped from
around old tobacco barns, from under kitchens and smokehouses. Then
water or water and urine was poured upon it until the mass was
thoroughly leached or exhausted. The percolate was collected in a
receptacle and evaporated, the salt redissolved, filtered, again
evaporated, and crystallized from the mother water.


       *       *       *       *       *



In this paper, read before the British Association, the author
explained that the "Telemeter System," invented by C.L. Clarke, of New
York, is a method by which the slow movement of a revolving hand of
any indicating instrument may be reproduced by the movement of a
similar hand at a distant place, using electricity to convey the
impulse. The primary hand moves until it makes electrical contact,
thus sending an impulse. It is here that all previous methods have
failed. This contact should be absolute and positive, for if it is
not, the receiver will not work in unison. The contact could often be
doubled by the jarring of the instrument, thus making the receiver
jump twice. Clarke has overcome this defect by so arranging his
mechanism that the faintest contact in the primary instrument closes
two platinum points in multiple arc with it, thus making a firm and
positive contact, which is not disturbed by any jar on the primary
contact. This gives the instruments a positive start for the series of
operations, instead of the faint contact which would be given, for
example, by the light and slowly moving hand of a metallic
thermometer. The other trouble with previous methods was that the
contact points would corrode, and, in consequence of such corrosion,
the instrument would fail to send impulses. Corrosion of the contacts
is due to breaking the circuit slowly on a small surface. This is
entirely remedied by breaking the circuit elsewhere than at the
primary contact, using a quick motion, and also by giving this
breaking contact large surface and making it firm. The instrument, as
applied to a thermometer, is made as follows: From the free end of the
light spiral of a metallic thermometer fixed at the other end, an arm,
C, is attached, the end of which moves over an arc of a circle when
the temperature varies. This end carries on either side of its
extremity platinum contacts which, when the thermometer is at rest,
lie between two other platinum points, A B, carried on radial arms.
Any variation in temperature brings a point on the thermometer arm in
contact with one of these points, and thus gives the initial start to
the series of operations without opposing any friction to the free
motion of the instrument. The first result is the closing of a short
circuit round the initial point of contact, so that no current flows
through it. Then the magnets which operate one set of pawls come into
play. The two contact points are attached to a toothed wheel in which
the pawls play, and these pawls are so arranged that they drive the
wheel whenever moved by their magnets; thus the primary contact is


In the receiver there is a similar toothed wheel carrying the hand of
the indicating instrument, and actuated at the same moment as the
transmitter. The primary contacts are so arranged that the contact is
made for each degree of temperature to be indicated. This series of
operations leaves the instruments closed and the pawls home in the
toothed wheel. To break the circuit another wire and separate set of
contacts are employed.

These are arranged on the arms carrying the pawls, and so adjusted
that no contact is made until after the toothed wheel has moved a
degree, when a circuit is closed and a magnet attracts an armature
attached to a pendulum. This pendulum, after starting, breaks the
circuit of the magnets which hold the pawls down, as well as of the
short-circuiting device. As the pendulum takes an appreciable time to
vibrate, this allows all the magnets to drop back, and breaks all
circuits, leaving the primary contacts in the same relation as at
first. The many details of the instruments are carefully worked out.
All the contacts are of a rubbing nature, thus avoiding danger from
dirt, and they are made with springs, so as not to be affected by jar.

The receiving instruments can be made recorders also by simple
devices. Thus, having only a most delicate pressure in the primary
instrument, a distinct ink record may be made in the receiver, even
though the paper be rough and soft. The method is applicable to steam
gauges, water indicators, clocks, barometers, etc., in fact, to any
measuring instrument where a moving hand can be employed.

       *       *       *       *       *


By WATSON SMITH, Lecturer in Chemical Technology in the Victoria
University, etc.

The Widnes Alkali Company, limited, to which I am indebted for
permission to describe this latest addition to a family of revolving
black ash furnaces, of late not only increasing in number, but also
individual size, has kindly allowed my friend, Mr. H. Baker, to
photograph the great revolver in question, and I have pleasure now in
throwing on the screen a picture of it, and also one of a revolver of
ordinary size, so as to render a comparison possible. The revolver of
ordinary size measures at most 18½ ft. long, with a diameter of 12½
ft. The boiling down pans connected with such a furnace measure 60 ft.
in length. Each charge contains four tons of salt cake, and some of
these revolvers get through 18 tons of salt cake per day and consume
13 cwt. of coal per ton of cake decomposed.

With regard to the larger revolver, it may be just said that the
Widnes Alkali Company has not at once sprung to the adoption of a
furnace of the immense size to be presently given, but in 1884 it
erected a revolver only about 3 ft. to 4 ft. short of the length of
that one, and having two discharging holes. The giant revolving
furnace to be described measures in length 30 ft. and has a diameter
of 12 ft. 6 in. Inside length is 28 ft. 6 in., with a diameter of 11
ft. 4 in. It is lined with 16,000 fire bricks and 120 fire-clay blocks
or breakers, weighing each 1¼ cwt. The bricks weigh per 1,000 about
four tons. The weight of salt cake per charge (i.e., contained in
each charge of salt cake, limestone, mud, and slack) is 8 tons 12 cwt.
For 100 tons of salt cake charged, there are also charged about 110
tons of lime mud and limestone and 55 tons of mixing slack. In a week
of seven days about 48 charges are worked through, weighing of raw
materials about 25 _tons per charge_. The total amount of salt cake
decomposed weekly is about 400 tons, and may be reckoned as yielding
240 tons of 60 per cent. caustic soda. As regards fuel used for
firing, this may be put down as 200 tons per week, or about 10 cwt.
per ton of salt cake decomposed. Also with regard to the concentration
of liquor from 20° Tw. to 50° Tw., there is sufficient of such
concentrated liquor evaporated down to keep three self-fired caustic
pots working, which are boiled at a strength of 80° Tw. Were it not
for this liquor, no less than seven self-fired pots would be required
to do this work, showing a difference of 80 tons of fuel.


The question may be asked, "Why increase the size of these huge pieces
of apparatus?" The answer, I apprehend, is that owing to competition
and reduction of prices, greater efforts are necessary to reduce
costs. With automatic apparatus like the black ash revolver, we may
consider no very sensible addition of man power would be needed, in
passing from the smallest sized to the largest sized revolver. Then,
again, we may, reckoning a certain constant amount of heat lost per
each revolver furnace of the small size, consider that if we doubled
the size of such revolver, we should lose by no means double the
amount of heat lost with the small apparatus; but only the same as
that lost in the small furnace _plus_ a certain fraction of that
quantity, which will be smaller the better and more efficient the
arrangements are. Then, again, there is an economy in iron plate for
such a large revolver; there is economy in expense on the engine power
and on fuel consumed, as well as in wear and tear.

Just to mention fuel alone, we saw that with an ordinary large sized
revolver, the coal consumption was 13 cwt. per ton of salt cake
decomposed in the black ash process; but with the giant revolver we
have been describing, that consumption is reduced to 10 cwt. per ton
of cake decomposed.


The question will be probably asked, How is it possible to get a flame
from one furnace to carry through such a long revolver and do its work
in fusing the black ash mixture effectively from one end to the other?
The furnace employed viewed in front looks very like an ordinary
revolver fireplace, but at the side thereof, in line with the front of
the revolver, at which the discharge of the "crude soda" takes place,
there are observed to be three "charging holes," rather than doors,
through which fuel is charged from a platform directly into the
furnace through those holes.

The furnace is of course a larger one than furnaces adjusted to
revolvers of the usual size. But the effect of one charging door in
front and three at the side, which after charging are "banked" up with
coal, with the exception of a small aperture above for admission of
air, is very similar to that sometimes adopted in the laboratory for
increasing heating effect by joining several Bunsen lamps together to
produce one large, powerful flame. In this case, the four charging
holes represent, as it were, the air apertures of the several Bunsen
lamps. Of course the one firing door at front would be totally
inadequate to supply and feed a fire capable of yielding a flame that
would be adequate for the working of so huge a revolver. As an effort
of chemical engineering, it is a very interesting example of what
skill and enterprise in that direction alone will do in reducing
costs, without in the least modifying the chemical reactions taking
place.--_Journal Soc. Chem. Industry._

       *       *       *       *       *


  [Footnote 1: A paper recently read before the British


So much has been said and written on and in relation to Portland
cement that further communications upon the subject may appear to many
of the present company to be superfluous. But is this really so? The
author thinks not, and he hopes by the following communication, to
place before this meeting and the community at large some facts which
have up to the present time, or until within a very recent date, been
practically disregarded or overlooked in the production of this very
important and valuable material, so essential in carrying out the
great and important works of the present day, whether of docks and
harbors, our coast defenses, or our more numerous operations on land,
including the construction of our railways, tunnels, and bridges,
aqueducts, viaducts, foundations, etc. The author does not propose to
occupy the time of this meeting by referring to the origin or the
circumstances attendant upon the early history of this material, the
manufacture of which has now assumed such gigantic proportions--these
matters have already been fully dealt with by other more competent
authorities; but rather to direct the attention of those interested
therein to certain modifications, which he considers improvements, by
means of which a large proportion of capital unnecessarily involved in
its manufacture may be set free in the future, the method of
manufacture simplified, the cost of manipulation reduced, and stronger
and more uniformly reliable cement be placed within the reach of those
upon whom devolves the duty and responsibility of constructing works
of a substantial and permanent character; but in order to do this it
will be necessary to allude to certain palpable errors and defects
which, in the author's opinion, are perpetuated, and are in general
practice at the present day.

Portland cement is, as is well known, composed of a mixture of chalk,
or other carbonate of lime, and clay--such as is obtained on the banks
of the Thames or the Medway--intimately mixed and then subjected to
heat in a kiln, producing incipient fusion, and thereby forming a
chemical combination of lime with silica and alumina, or practically
of lime with dehydrated clay. In order to effect this, the usual
method is to place the mechanically mixed chalk and clay (technically
called slurry), in lumps varying in size, say, from 4 to 10 lb., in
kilns with alternate layers of coke, and raise the mass to a glowing
heat sufficient to effect the required combination, in the form of
very hard clinker. These kilns differ in capacity, but perhaps a fair
average size would be capable of producing about 30 tons of clinker,
requiring for the operation, say, from 60 to 70 tons of dried slurry,
with from 12 to 15 tons of coke or other fuel. The kiln, after being
thus loaded, is lighted by means of wood and shavings at the base,
and, as a matter of course, the lumps of slurry at the lower part of
the kiln are burned first, but the moisture and sulphurous gases
liberated by the heat are condensed by the cooler layers above, and
remain until the heat from combustion, gradually ascending, raises the
temperature to a sufficient degree to drive them further upward, until
at length they escape at the top of the kiln. The time occupied in
loading, burning, and drawing a kiln of 30 tons of clinker averages
about seven days. It will be readily understood that the outside of
the clinker so produced must have been subjected to a much greater
amount of heat then was necessary, before the center of such clinker
could have received sufficient to have produced the incipient fusion
necessary to effect the chemical combination of its ingredients; and
the result is not only a considerable waste of heat, but, as always
occurs, the clinker is not uniformly burnt, a portion of the outer
part has to be discarded as overburnt and useless, while the inner
part is not sufficiently burnt, and has to be reburned afterward.
Moreover, the clinker, which is of excessively hard character, has to
be reduced by means of a crusher to particles sufficiently small to be
admitted by the millstones, where it is ground into a fine powder, and
becomes the Portland cement of commerce.

This process of manufacture is almost identical in principle and in
practice with that described and patented by Mr. Joseph Aspden in the
year 1824; and though various methods have been patented for utilizing
the waste heat of the kilns in drying the slurry previous to
calcination, still the main feature of burning the material in mass in
large and expensive kilns remained the same, and is continued in
practice to the present day. The attention of the author was directed
to this subject some time since in consequence of the failure of a
structure in which Portland cement formed an essential element, and he
had not proceeded far in his investigation of the cause of the failure
when he was struck with what appeared to him to be the unscientific
method adopted in its manufacture, and the uncertain results that must
necessarily accrue therefrom. Admitting, in the first place, that the
materials employed were considered the best and most economical for
the purpose readily accessible, viz., chalk and an alluvial deposit
found in abundance on the banks of the Thames and the Medway, and
being intimately mixed together in suitable proportions, was it
necessary, in order to effect the chemical combination of the
ingredients at an intense heat, to employ such massive and expensive
structures of masonry, occupying such an enormous space of valuable
ground, with tall chimney stacks for the purpose of discharging the
objectionable gases, etc., at such a height, in order to reduce the
nuisance to the surrounding neighborhood? Again, was it possible to
effect the perfect calcination of the interior of the lumps alluded to
without bestowing upon the outer portions a greater heat than was
necessary for the purpose, causing a wasteful expenditure of both
time and fuel? And further, as cement is required to be used in the
state of powder, could not the mixture of the raw materials be
calcined in powder, thereby avoiding the production of such a hard
clinker, which has afterward to be broken up and reduced to a fine
powder by grinding in an ordinary mill?

The foregoing are some of the defects which the author applied himself
to remove, and he now desires to draw attention to the way in which
the object has been attained by the substitution of a revolving
furnace for the massive cement kilns now in general use, and by the
application of gaseous products to effect calcination, in the place of
coke or other solid fuel. The revolving furnace consists of a
cylindrical casing of steel or boiler plate supported upon steel
rollers (and rotated by means of a worm and wheel, driven by a pulley
upon the shaft carrying the worm), lined with good refractory fire
brick, so arranged that certain courses are set so as to form three or
more radial projecting fins or ledges. The cylindrical casing is
provided with two circular rails or pathways, turned perfectly true,
to revolve upon the steel rollers, mounted on suitable brickwork, with
regenerative flues, by passing through which the gas and air severally
become heated, before they meet in the combustion chamber, at the
mouth of the revolving furnace. The gas may be supplied from slack
coal or other hydrocarbon burnt in any suitable gas producer (such,
for instance, as those for which patents have been obtained by Messrs.
Brook & Wilson, of Middlesbrough, or by Mr. Thwaite, of Liverpool),
which producer may be placed in any convenient situation.

The cement mixture or slurry, instead of being burnt in lumps, is
passed between rollers or any suitable mill, when, it readily falls
into coarse dry powder, which powder is thence conveyed by an elevator
and fed into the revolving furnace by means of a hopper and pipe,
which, being set at an angle with the horizon, as it turns gradually
conveys the cement material in a tortuous path toward the lower and
hotter end, where it is discharged properly calcined. The material
having been fed into the upper end of the cylinder falls through the
flame to the lower side of it; the cylinder being in motion lifts it
on its advancing side, where it rests against one of its projecting
fins or ledges until it has reached such an angle that it shoots off
in a shower through the flame and falls once more on the lower side.
This again causes it to travel in a similar path, and every rotation
of the cylinder produces a like effect, so that by the time it arrives
at the lower and hotter end it has pursued a roughly helical path,
during which it has been constantly lifted and shot through the flame,
occupying about half an hour in its transit.

To some who have been accustomed to the more tedious process of kiln
burning, the time thus occupied may appear insufficient to effect the
combinations necessary to produce the required result; but it will be
seen that the conditions here attained are, in fact, those best suited
to carry out effectively the chemical changes necessary for the
production of cement. The raw material being in powder offers every
facility for the speedy liberation of water and carbonic acid, the
operation being greatly hastened by the velocity of the furnace gases
through which the particles pass. That such is practically the case is
shown by the following analysis of cement so burnt in the revolving
furnace or cylinder:

                                         Per cent.
    Carbonic acid, anhydrous                0.4
    Sulphuric acid, anhydrous               0.26
    Silica soluble                         24.68
    Silica insoluble                        0.6
    Alumina and oxide of iron              10.56
    Lime                                   61.48
    Magnesia, water, and alkalies           2.02

Again, fineness of the particles results in their being speedily
heated to a uniform temperature, so that they do not serve as nuclei
for the condensation of the moisture existing in the furnace gas. The
calcined material, on reaching the lower end of the furnace, is
discharged on to the floor or on to a suitable "conveyer," and removed
to a convenient locality for cooling and subsequent grinding or
finishing. It, however, is not in the condition of hard, heavy
clinkers, such as are produced in the ordinary cement kiln, which
require special machinery for breaking up into smaller pieces before
being admitted between the millstones for the final process of
grinding; nor does it consist of an overburnt exterior and an
underburnt core or center portion; but it issues from the cylindrical
furnace in a condition resembling in appearance coarse gunpowder, with
occasional agglutinations of small friable particles readily reduced
to fine powder in an ordinary mill, requiring but small power to work,
and producing but little wear and tear upon the millstones. The
operation is continuous. The revolver or furnace, once started, works
on night and day, receiving the adjusted quantity of powdered material
at the upper or feed end, and delivering its equivalent in properly
burnt cement at the opposite end, thus effecting a great saving of
time, and preventing the enormous waste of heat and serious injury to
the brickwork, etc., incidental to the cooling down, withdrawing the
charge, and reloading the ordinary kiln.

Cement, when taken from the furnace, weighed 110 lb. per bushel.
Cement, when ground, leaving 10 percent. on sieve with 2,500 holes to
the inch, weighed 121 lb. per bushel, and when cold 118 lb. per
bushel. When made into briquettes, the tensile breaking strain upon
the square inch:

    At  4 days was       410 lb. per square inch.
    At  6 days  "        610  "   "     "     "
    At 14 days  "        810  "   "     "     "
    At 49 days  "        900  "   "     "     "
    At 76 days  "      1,040  "   "     "     "

A cylindrical furnace, such as the author has described, is capable of
turning out at least 20 tons of good cement per day of twenty-four
hours, with a consumption of about 3 tons of slack coal. It will be
readily understood that these furnaces can be worked more economically
in pairs than singly, as they can be so arranged that one producer may
furnish a sufficient quantity of gas for the supply of two cylinders,
and the same labor will suffice; but in order to provide for possible
contingencies the author advises that a spare gas producer and an
extra furnace should be in readiness, so that by a simple arrangement
of valves, etc., two cylinders may always be in operation, while from
any cause one may be undergoing temporary repairs, and by this means
any diminution in the output may be avoided.

The author considers it unnecessary here to discuss either the
advantages or the economy of fuel effected by the employment of gas
producers for such a purpose. These have been abundantly proved in
steel and glass making industries, where a saving of from 50 to 70 per
cent. of the fuel formerly employed has been made. Their cost is
small, they occupy little room, they can be placed at any reasonable
distance from the place where the gas is to be burnt; any laborer can
shovel the slack into them, and they do not require constant skilled
supervision. It is claimed by the author of this paper that the
following are among the many advantages derivable from the adoption of
this method of manufacturing Portland cement, as compared with the old

    (1) Economy of space--the furnaces, with their appurtenances,
    requiring only about one-fourth the space of what would be
    occupied by the ordinary kilns for producing the same quantity
    of finished cement.

    (2) Continuous working, and consequent economy of fuel lost by
    cooling and subsequent reheating of the kiln walls.

    (3) Economy of repairs, which are of a simple and comparatively
    inexpensive character, and of much less frequent occurrence, as
    the continuous heat avoids the racking occasioned by the
    alternate heating and cooling.

    (4) Economy in first cost.

    (5) Economy in grinding, a friable granular substance being
    produced instead of a hard clinker, whereby crushers are quite
    abolished, and the wear and tear of millstones greatly

    (6) Economy of labor, the conveyance to and removal from, the
    revolving furnace being conducted automatically by mechanical
    elevators and conveyers.

    (7) Improved quality of the cement, from non-mixture with
    fuel, ash, or other impurities, and no overburning or
    underburning of the material.

    (8) Thorough control, from the facility of increasing or
    diminishing the flow of crushed slurry and of regulating the
    heat in the furnace as desirable.

    (9) Absence of smoke and deleterious gases.

It is well known that in some localities the materials from which
Portland cement is made are of such a powdery character that they have
to be combined or moulded into balls or bricks previous to calcination
in the ordinary way, thus entailing expense which would be entirely
obviated by the adoption of the patent revolving furnace, as has been
proved by the author in producing excellent cement with a mixture of
slag sand from the blast furnaces of the Cleveland iron district, with
a proper proportion of chalk or limestone, which, in consequence of
the friable nature of the compound, he was unable to burn in the
ordinary cement kiln, but which, when burnt in the revolving furnace,
gave the most satisfactory results. The cement so made possessed
extraordinary strength and hardness, and it has been a matter of
surprise that iron masters and others have not adopted such a means of
converting a waste material--which at the present time entails upon
its producers constant heavy outlay for its removal--into a
remunerative branch of industry by the expenditure of a comparatively
small amount of capital. The demand for Portland cement has increased
and is still increasing at a rapid ratio. It is being manufactured
upon a gigantic scale.

Great interests are involved; large sums of money are being expended
in the erection and maintenance of expensive plant for its production;
and the author submits that the development of any method which will
improve the quality and at the same time reduce the cost of
manufacture of this valuable material will tend to increase the
prosperity of one of our great national industries, and stimulate
commercial enterprise. Works are in progress for manufacturing cement
by this improved process, and the author trusts the time is not far
distant when the unsightly structures which now disfigure the banks of
some of our rivers will be abolished--the present cement kilns, like
the windmills once such a common feature of our country, being
regarded as curiosities of the past, and cement manufacturers cease to
be complained of as causing nuisances to their neighbors.

       *       *       *       *       *


We illustrate in the annexed engraving the microphone-telephone
constructed by Messrs. Mix & Genest, of Berlin, which, after extended
trials, has been adopted in preference to others by the imperial
postal department of Germany. There are now more than 5,000 of these
instruments in use, and we need scarcely mention that the invention
has been patented in many countries.

In some microphones a rattling noise is frequently occasioned, which
borne along with the sound of the human voice causes an audible
disturbance in the telephone. The chief cause of these disturbances
may be ascribed to the fact that the carbon rollers in their journals,
rest loose in the flutings of the beam, which is fastened to the sound
plate. Owing to the shocks given to the entire apparatus, and
independent of the oscillations of the sound plate, they are set in
motion and roll to and fro in their bearings.

In microphones in which the sound plates are arranged vertically (as
shown in Fig. 2), these disturbances assume such a character that
there is no possibility of understanding the speaker, for in this case
the horizontally directed oscillations of the sound plate, _m_, cause
themselves a backward and forward motion on the part of the carbon
rollers without increasing or decreasing at the same time the lying-on
pressure of the roller journals, and by doing so bring the places of
contact one on the other, and thus occasion a conducting resistance of
greater or less force. This circumstance serves as an explanation of
the reason why the sound plates in Ader's microphones are not arranged
vertically, although this way of arranging them offers many advantages
over a horizontal or slightly inclined arrangement of the sound
plates. Speaking is more convenient in the vertical arrangement, and
moreover the plates can be fitted on to instruments better in this

All the drawbacks just enumerated and found in Ader's microphones are
avoided in the apparatus made by Messrs. Mix & Genest. A sort of
braking contrivance operates on the carbon rollers in such a way as to
prevent their journals from lying on the lower points in the flutings
of the beams. Thus, for instance, if in a microphone with a horizontal
sound plate, as illustrated in Fig. 3, the carbon rollers are pressed
upward by outward force, it is evident that only a very trifling
rolling and disturbing motion can occur, and only small pieces of
carbon can be knocked off, which would act injuriously as a secondary
contact. The same may be said of the journals of microphones with
vertical sound plates, as represented in Fig. 2, when the carbon
rollers are pressed in the direction of the arrow, _p_, that is to
say, against the sound plate. In this case the journals, _a_, are
fixed in the flutings of the beams, _b_, in a direction given them by
the power and gravity operating on them, which is clearly represented
in the accompanying design, Fig. 2.

[Illustration: FIG. 1.
               FIG. 2.
               FIG. 3.

In all such cases the regulating contrivance applied to brake the
carbon rollers in their motion has the result that only the
oscillations transmitted from the sound plate on to the contacts come
in operation, whereas disturbing mechanical shocks resulting from any
outward influences occasion very insignificant vibrations, which are
not perceptible in the telephone. The separate contacts thus form a
firm system with the sound plate, so that the former are influenced in
their motions and effects solely and alone by the shocks and
oscillations which operate direct on these sound plates. The roller
motion of the carbon is thus removed, and the distinctness of the
words spoken is greatly augmented.

The above Figs. 1 and 2 show the microphone in side view and in cross

A metal ring, R (see Fig. 1), is fastened by means of the four screws,
_r_{1}_ _r_{2}_ _r_{3}_ _r_{4}_, on a wooden mouthpiece. In a recess of the
above ring is the diaphragm, M, which is provided on its outer edge
with an India rubber band and is held in position by the two clamps, _a_
and _a_{1}_. The diaphragm is cut out of finely fibered firwood and is
well lacquered to preserve it against dampness. On it there are two
carbon beams, _b_, and in the perforations of the latter are the
journals of the carbon rollers, _k_. The alterations in contact take
place in the touching points. The cross piece, _f_, that runs straight
across the carbon rollers serves as a braking contrivance, which is
regulated as may be necessary by the large projecting screws.

Fig. 3 shows the apparatus in cross section. T is the mouth piece, R
the metal ring, M the diaphragm, _f_ the breaking cross piece. On the
latter is a metal block fastened by means of two screws. On this metal
block is a soft elastic strip (d) of felt or similar material. The
letters _s_ and _s_ indicate the regulating screws for the braking

The excellent qualities of other microphones, in particular their
extreme sensibility for the very least impressions, are undeniable;
but it is just this sensibility that is the cause of the complaints
made by the public. In practical use this overgreat sensibility proves
to be a fault.

In the apparatus constructed by Messrs. Mix and Genest the well-known
deficiencies of other systems are avoided. The effect of the sound and
the distinctness of the human voice are clearer and far more
intelligible. One simple regulation of the microphone suffices for the
installation, for there is no danger of its getting out of order.
Owing to its peculiar construction, this new microphone is very firm
and solid, and for this very reason offers another advantage, namely,
the possibility of transmitting sound over very long distances. In the
competitive trials instituted by order of the imperial postal
department, apparatus of various systems and constructions were
subjected to tests, and the apparatus we are speaking of showed the
favorable results just mentioned. This microphone has overcome in
particular the difficulties connected with the using of combined lines
above and below ground, and with the aid of it the excellent
telephonic communication is carried on in Berlin, in which city the
telephone net is most extensive and complicated. At the same time this
microphone transmits the sound over long distances (up to 200 kilom.
even) in the most satisfactory manner. Another peculiar advantage of
this construction is that it exercises a very small inductive effect
on cables and free lines, and consequently the simultaneous speaking
on parallel lines causes but little disturbance.

After repeated trials made by the German imperial postal department
with the microphones constructed by Messrs. Mix and Genest, these
apparatus have been introduced in the place of the telephones and
Bell-Blake microphones hitherto used in the telephone service. At
present we understand there are about 8,000 of these apparatus in use.

       *       *       *       *       *


Mr. G. Fahrig, of Eccles, Lancashire, has invented a new process of
refining sugar through electrolysis. The brown sugar is decolorized by
means of ozone produced by electric currents of high tension from a
dynamo. The electrodes consist of metal grills covered with platinum
or some other inoxidizable metal, and are placed in a vat with the
intervention of perforated earthenware plates. After being ground and
dried in hot air, the crude sugar is placed between the plate and the
grills, and the discharges passing between the electrodes produce
ozone, which separates the sugar from the coloring matter. To purify
the sugar still further, Mr. Fahrig dries it and places it in another
vat, with carbon or platinum conducting plates separated by a porous
partition. The sugar is placed on one side of this partition, and
water circulates on the other side.

The current from a dynamo of feeble tension is sent through the vat
between the plates. The water carries along the impurities separated
by the current, and the sugar is further whitened and refined.


The accompanying figure shows a series of four vats arranged one above
another, in order to permit the water to circulate. Here _i_ and _h_
represent the plates connected with the poles of the dynamo through
the conductors, _f_ and _g_; _m_ represents the porous partition; L,
the spaces filled with sugar; and _l_, the compartments in which the
water circulates.--_La Lumiere Electrique._

       *       *       *       *       *



We give a description of a meter we made in June, 1883. You will find
a cross section of the meter and also a printed dial we had made at
the time. We called it an ampere register, but no doubt we would give
it a better name to-day. The meter consisted of a glass tube, _c_,
both ends of which were fitted into two bent pieces of piping, D and
F, as shown. Through these bent tubes, D and F, passed the wires, a
and _b_, which were connected to the binding posts, A and B. The part
of the wire where it passed into the tubes was well insulated. At the
ends, _a'_ and _b'_, was connected the coil, R, which consisted simply
of a few turns of copper wire whose diameter was less than the leading
wires, _a_ and _b_. To the tube, D, was attached a square tube, E,
which had a little opening at the top so as to permit a small
undershot wheel, I, to revolve freely. This undershot wheel was well
pivoted and constructed very light. To the axis of this wheel was
connected another system of wheels with indicators, as shown, J. Now
the tubes, E and F, were connected to a reservoir, G. This reservoir
consisted of a square tank, in the inside of which were soldered in an
alternating manner square sheets of copper as shown in the drawing,
_g_ _g'_ _g''_ _g'''_ ... These sheets acted as diffusers. These
plates or sheets presented a very large surface. On the outside of the
tank, G, were also diffusers, _h_ _h'_ ... arranged all round and
presenting an appearance as if two books were open so as to form a
square with their covers, the leaves being the diffusers. The
diffusers on the outside were at right angles to those inside.


The action of the meter was thus: When a current passes through the
coil, R, it heats the liquid at the place, thus causing a circulation,
the warm liquid ascending while the cold liquid descends as shown by
the arrows. This circulation causes the undershot wheel to revolve,
and its revolutions are registered by the clockwork. The stronger the
current, the more the heat, and thus the more rapid the circulation.
The warm liquid once in the tank, which is of a reasonable size, will
impart its heat to all the diffusers. The surface of the glass tube,
etc., is very small in comparison to the surface of the tank. It will
be seen that the function of this apparatus is independent of the
outward temperature, for the motion of the liquid is due only to that
heat which is generated by the current. When the current does not
pass, it is evident that the liquid, at whatever temperature it may
be, does not circulate, as all parts are of the same temperature; but
the moment the current passes, a difference is produced, which causes
a circulation in proportion to the current. We may mention that we
tried various liquids, and give preference to pure olive oil. It will
also be seen that this meter is good for alternating currents. In
conclusion, we may remark that the tests we made gave satisfaction,
and we wanted to publish them, but that Mr. Jehl was called away to
fit up the Edison exhibit in the Vienna exhibition for the Societe
Electrique Edison of Paris. After the exhibition we began our work
upon our disk machine, and had almost forgotten our meter. The whole
apparatus is mounted on a base, K.

[Illustration: DIAL FACE.]

Brünn, Sept. 26, 1887.

       *       *       *       *       *


  [Footnote 1: From a paper read before the National Electric Light
  Association, New York, August, 1887.]


The idea of employing secondary batteries for propelling vehicles is
almost contemporaneous with the discovery of this method of storing
energy. To Mr. Plante, more than to any other investigator, much of
our knowledge in this branch of electrical science is due. He was the
first to take advantage of the action of secondary currents in voltaic
batteries. Plante is a scientist of the first grade, and he is a
wonderfully exact experimenter. He examined the whole question of
polarization of electrodes, using all kinds of metal as electrodes and
many different liquids as electrolytes, and during his endless
researches he found that the greatest useful effect was produced when
dilute sulphuric acid was electrolyzed between electrodes of metallic

A set of Plante's original cells was exhibited for the first time in
March, 1860, before the Paris Academy of Sciences. Scientists admired
and praised it, but the general public knew nothing of this great
discovery thus brought to notice. Indeed, at that period little
commercial value could be attached to such apparatus, since the
accumulator had to be charged by means of primary batteries, and it
was then well known that electrical energy, when produced by chemical
means in voltaic cells, was far too expensive for any purpose outside
the physical laboratory or the telegraph office.

It was twenty years after this exhibition at the Academy of Sciences
in Paris that public attention was drawn to the importance of storage
batteries, and that Mr. Faure conceived the idea of constructing
plates consisting of lead and oxides of lead. At that time the
advantages accruing through a system of electrical storage could be
fully appreciated, since electrical energy was already being produced
by mechanical means through the medium of dynamo-electric machines.

It was the dynamo machine which created the demand for the storage
battery, and the latter was introduced anew to the public at large
and to the capitalist with great pomp and enthusiasm. One of Faure's
accumulators was sent to Sir William Thomson, and this eminent
scientist in the course of experiments ascertained that a single cell,
weighing 165 lb., can store two million foot-pounds of energy, or one
horse power for one hour, and that the loss of energy in charging did
not exceed 15 per cent. These results appeared highly encouraging.
There we had a method of storing that could give out the greater part
of the energy put in. The immense development which the electric
transmission of energy was even at that early day expected to undergo
pointed to the fact that a convenient method of receiving large
quantities of transmitted energy, and of holding it in readiness until
wanted, must be of the highest importance. Numerous applications of
the Faure battery were at once suggested, and the public jumped to the
conclusion that a thing for which so many uses could be instantly
found must necessarily be a profitable investment, and plenty of money
was provided forthwith, not with the idea of commencing careful
experiments and developing the then crude invention, which would have
been the correct thing, but for manufacturing tons of accumulators in
their first and immature form.

I need not describe the disappointments which followed the first
unfulfilled hopes, nor repeat the criticism that was heaped upon the
heads of the early promoters. Those early hopes were untimely and
unreasonable. A thousand difficulties had to be overcome--scientific
difficulties and manufacturing difficulties. This invention, like most
others, had to go through steady historical developments and
evolution, and follow the recognized laws of nature, which are against
abnormal and instantaneous maturity. The period of maturity has also
been retarded by injudicious treatment, but the ultimate success was
inevitable. Great advances have been made within the last few years,
and I propose now to offer a few facts and figures relating to the
present state of the subject with reference to the application of
storage batteries to locomotive purposes. It is not within the
province of this paper to discuss all the different inventions of
secondary batteries nor to offer any suggestions with regard to
priority, therefore I will confine myself to general statements. I am
aware of the good work that was done in the United States by Kirchhoff
twenty-six years ago, and of the more recent work of Mr. Brush, of
Cleveland, Mr. Julien and others, but I am more particularly
acquainted with the recent achievements of the Electrical Accumulator
Company, who own the rights of the Electrical Power Storage Company,
of London. I have used the batteries of the latter company for
propelling electric boats and electric street cars. The first of the
boats was the Electricity, which was launched in September, 1882, and
which attained a speed of seven miles an hour for six consecutive
hours. Since then a dozen electric boats of various sizes have been
fitted up and worked successfully by means of storage batteries and
motors of my design. The most important of these were the launch Volta
and another similar craft, which is used by the Italian government for
torpedo work in the harbor of Spezia. On the measured mile trial trips
the Italian launch gave an average speed of 8.43 miles an hour with
and against the tide. The hull of this vessel was built by Messrs.
Yarrow & Co., and the motors were manufactured by Messrs. Stephens,
Smith & Co., of London. The Volta, which was entirely fitted by the
latter firm, is 37 feet long and 7 feet beam. She draws 2'6" of water
when carrying 40 persons, for whom there is ample sitting
accommodation. There are 64 cells in this boat. These are placed as
ballast under the floor, and actuate a pair of motors and a screw
coupled direct to the armature shaft running at 700 revolutions a
minute. We crossed the English Channel with this boat in September of
last year, leaving Dover at 10:40 in the morning, arriving at Calais
at 2:30 P.M.; stayed about an hour in the French harbor for luncheon
and floated into Dover docks the same evening, at 6:30, with full
speed. The actual distance traversed without entirely discharging the
cells was 54 miles. The current remained constant at 28 amperes until
5 P.M., and it only dropped to 25 amperes at the completion of the
double voyage between England and France. Several electric launches
are now being constructed in London, and one in New York by the
Electrical Accumulator Company.

M. Trouve exhibited a small boat and a tricycle, both worked by Plante
accumulators, at Paris, in 1881.

The first locomotive actuated by storage batteries was used at a
bleaching works in France in 1882. During the same year I designed an
electric street car for the storage company, and this was tried on the
lines of the West Metropolitan Tramways in March, 1883. It had
accommodation for 46 passengers. This car had many defects, and I
reconstructed it entirely, and ran it afterward in its improved form
on the South London Tramways, and also on a private track at Millwall,
where it is now in good condition, and I have a similar car in Berlin.
M. Phillippart exhibited a car in Paris and M. Julien made successful
experiments in Brussels, Antwerp, and Hamburg. Mr. Elieson is running
storage battery locomotives in London. Mr. Julien has also been
experimenting with a car in New York, and I believe one is in course
of construction for a line in the city of Boston. Messrs. W. Wharton,
Jr. & Co. have a storage battery car running at Philadelphia on Spruce
and Pine streets, and this energetic firm is now fitting up another
car with two trucks, each carrying an independent motor, similar to my
European cars.

I have mentioned all these facts in order to show that there is a
considerable amount of activity displayed in the matter of storage
batteries for street cars, and that continued and substantial progress
is being made in each successive case. The prejudices against the
application of secondary batteries are being rapidly dispelled, and
there are indications everywhere that this method of propulsion will
soon take a recognized place among the great transit facilities in the
United States. I feel convinced that this country will also in this
respect be far ahead of Europe before another year has passed over our

There are several popular and I may say serious objections to the
employment of storage batteries for propelling street cars. These
objections I will now enumerate, and endeavor to show how far they are
true, and in what measure they interfere with the economical side of
the question.

First objection: The loss of energy, which amounts in practice to 20
and sometimes 30 per cent. Now, every method of storing or
transmitting energy involves some waste, but in saying this we need
not condemn the system, for after all the term efficiency is only a
relative one. For instance, a 10 horse power steam engine consumes
three times as much fuel per horse power hour as a 1,000 horse power
engine does, yet this small engine must be, and is regarded as, one of
the most economical labor-saving appliances known to us. Considered as
a heat engine, the efficiency of the most economical steam motor is
but ten per cent.--90 per cent of the available units of heat
contained in coal being lost during its transformation into mechanical
energy. Thus, if we find that the storage battery does not return more
than 70 per cent, of the work expended in charging it, we ought not to
condemn it on that account until we have ascertained whether this low
efficiency renders the system unfit for any or all commercial
purposes. It is needless to go into figures in order to show that,
when compared with animal power, this objection drops into

The second, more formidable, objection relates to the weight of
storage batteries--and this involves two disadvantages, viz., waste of
power in propelling the accumulator along with the car, and increased
pressure upon the street rails, which are only fitted to carry a
maximum of 5 tons distributed over 4 points, so that each wheel of an
ordinary car produces a pressure of 1¼ tons upon a point of the rail
immediately under it.

The last mentioned objection is easily overcome by distributing the
weight of the car with its electrical apparatus over 8 wheels or 2
small trucks, whereby the pressure per unit of section on the rails is
reduced to a minimum. With regard to the weight of the storage
batteries, relatively to the amount of energy the same are capable of
holding and transmitting, I beg to offer a few practical figures.
Theoretically, the energy manifested in the separation of one pound of
lead from its oxide is equivalent to 360,000 foot pounds, but these
chemical equivalents, though interesting in themselves, gives us no
tangible idea of the actual capacity of a battery.

Repeated experiments have shown me that the capacity of a secondary
battery cell varies with the rate at which it is charged and
discharged. For instance, a cell such as we use on street cars gave a
useful capacity of 137.3 ampere hours when discharged at the average
rate of 45.76 amperes, and this same cell yielded 156.38 ampere hours
when worked at the rate of 22.34 amperes. At the commencement of the
discharge the E.M.F of the battery was 2.1 volts, and this was allowed
to drop to 1.87 volts when the experiment was concluded. The entire
active material contained in the plates of one cell weighed 11.5 lb.,
therefore the energy given off per pound of active substance at the
above high rate of discharge was 62.225 foot pounds, and when
discharging at the lower rate of 22.34 amperes the available useful
energy was 72.313 foot pounds, or nearly 2.2 electrical horse power
per pound of active matter. But this active substance has to be
supported, and the strength or weight of the support has to be made
sufficiently great to give the plate a definite strength and
durability. The support of the plates inclusive of the terminals above
referred to weighs more than the active material, which consists of
peroxide of lead and spongy lead; so that the plates of one cell weigh
actually 26.5 pounds. Add to this the weight of the receptacle and
acid, and you get a total of about 41 pounds per cell when in working
order. Seventy of these cells will propel an ordinary street car for
four hours and a half, while consuming the stored energy at the rate
of 30 amperes, or over 5.6 electrical horse power. The whole set of
seventy cells weighs 2,870 lb., which is barely one-fifth of the
entire weight of the car when it carries forty adult passengers.
Therefore the energy wasted in propelling the accumulator along with a
ear does not amount to more than 20 per cent. of the total power, and
this we can easily afford to lose so long as animal power is our only
competitor. From numerous and exhaustive tests with accumulators on
cars in this country and abroad, I have come to the conclusion that
the motive power for hauling a full-sized street car for fifteen hours
a day does not exceed $1.75, and this includes fuel, water, oil,
attendance, and repairs to engine, boiler, and dynamo. We have thus an
immense margin left between the cost of electric traction and horse
traction, and the last objection, that relating to the depreciation of
the battery plates, can be most liberally met, and yet leave ample
profits over the old method of propulsion by means of animals.

The advantages of storage battery street cars for city traffic are
self-evident, so that I need not trouble you with further details in
this respect, but I would beg those who take an interest in the
progress of the electric locomotive to give this subject all the
consideration it deserves, and I would assure them that the system
which I have advocated in this brief but very incomplete sketch is
worthy of an extended trial, and ready for the purposes set forth.
There is no reason why those connected with electric lighting
interests in the various cities and towns should not give the matter
their special attention, as they are the best informed on electrical
engineering and already have a local control of the supply of current
needed for charging.

In the car which we use in Philadelphia there are actually 80 cells,
because there are considerable gradients to go over. Each cell weighs
40 pounds and the average horse power of each battery is six.
Sometimes we only use two horse power and sometimes, going up grades
of 5 per cent., we use as much as 12 horse power, but the average rate
is 6 electrical horse power. With reference to the weight of
passengers on the cars, we have never carried more than 50 passengers
on that car, because it is impossible to put more than 50 men into it.
There are seats for 24, and the rest have to stand on the platforms or
in the aisle.

The changing of the batteries takes three minutes with proper
appliances. One set of cells is drawn out by means of a small winch
and a freshly charged set is put in. It takes the same time to charge
the battery as it does to discharge it in the working of the cars, so
one reserve set would be sufficient to keep the car continually

The loss of energy from standing about is probably nothing. If a
battery were to stand charged for three months in a dry case, the loss
of energy might be in three months 10 per cent. I purposely had a set
of cells standing for two years charged and never used them. After two
years there was still a small amount of energy left. So as regards
the loss of energy in a battery standing idle, it is practically
nothing, because no one would think of charging a battery and letting
it stand for three months or a year.

I have had them stand three or four months and I could hardly
appreciate the loss going on, provided always that the cells are
standing on a dry floor. If the exterior of the box be moist, or if it
stands on a moist floor, there will naturally be a surface leakage
going on: but where there is no surface leakage the mere local action
between the oxides and metallic lead will not discharge the battery
for a very considerable time.

I have made experiments in London with a loaded car pulled by two
horses. I put a dynamometer between the attachment of the horse and
the car, so as to ascertain exactly the amount of pull, measured in
pounds multiplied by the distance traversed in a minute. You will be
surprised to know that two horses, when doing their easiest work,
drawing a loaded car on a perfectly level road, exert from two to
three horse power. I have mentioned a car in Philadelphia where we use
between two and twelve horse power. A horse is capable of exerting
eight horse power for a few minutes, and when a car is being driven up
grades, such as I see in Boston, for instance, pulling a load of
passengers up these grades, the horses must be exerting from 12 to 16
horse power, mechanical horse power. That is the reason that street
car horses cannot run more than three or four hours out of the
twenty-four. If they were to run longer, they would be dead in a few
weeks. If they run two hours a day, they will last three or four

The life of the cells must be expressed upon the principle of ampere
hours or the amount of energy given off by them. Street car service
requires that the cells work their hardest for fifteen or sixteen
hours a day. The life of the cells has to be divided; first, into the
life of the box which contains the plates. This box, if appropriately
constructed of the best materials, will last many years, because there
is no actual wear on it. The life of the negative plates will be very
considerable, because no chemical action is going on in the negative
plate. The negative plate consists almost entirely of spongy lead, and
the hydrogen is mechanically occluded in that spongy lead. Therefore
the depreciation of the battery is almost entirely due to the
oxidation of the positive plates. If we were to make a lead battery of
plates ¼ inch thick, it would last many years; but for street car
work that would be far too heavy. Therefore we make the positive
plates a little more than one-eighth of an inch thick. I find that the
plates get sufficiently brittle to almost fall to pieces after the car
has run fifteen hours a day for six months. The plates then have to be
renewed. But this renewal does not mean the throwing away of the
plates. The weight is the same as before, because no consumption of
material takes place. We take out peroxide of lead instead of red
lead. That peroxide, if converted, produces 70 per cent. of metallic
lead, so that there is a loss of 30 per cent. in value. Then comes the
question of the manufacture of these positive plates, which, I
believe, at the present day are rather expensive. But I believe the
time will come when battery plates will be manufactured like shoe
nails, and the process of renewing the positive plates will be a very
cheap one.

I ascertained in Europe that the motive power costs 2 cents per car
mile; that is, the steam power and attendance for charging the
batteries. We have to allow twice as much for the depreciation of a
battery at the present high rate at which we have to pay for the
battery--$12 for each cell. But I believe that as soon as the storage
battery industry is sufficiently extended, the total cost for
propelling these cars will not be more than six cents a mile, or about
one half the cost of the cheapest horse traction.

I have made some very careful observations on the cable tramway in
Philadelphia, which is quite an extensive system. I have never been
able to ascertain the exact amount of waste in pulling the cable
itself; but I have it on the authority of certain technical papers
that there is a waste of about eighty per cent. I do not intend to
depreciate cable or any other tramways, but there is a difficulty
about introducing cable tramways. It is necessary to dig up the
streets and interfere with the roadways. I have been told that the
cable arrangements in Philadelphia cost $100,000 a mile, and that the
cable road in San Francisco cost more than that. One of the directors
of the cable company in Philadelphia told me that if he had seen the
battery system before the introduction of the cable, he would probably
have made up his mind in favor of the former. The wear and tear in the
case of the storage system is also considerable. There is a waste of
energy in the dynamo; secondly, in the accumulator charged by that
dynamo; thirdly, in the motor which is driven by the accumulator; and
fourthly, in the gearing that reduces the speed of the motor to the
speed required by the car axles. It would be difficult to make a motor
run at the rate of eighty revolutions per minute, which is the number
of revolutions of the street car axle when running at the rate of ten
miles an hour. Take all these wastes, and you find in practice that
you do not utilize more than 40 per cent. of the energy given by the
steam engine. But this is quite sufficient to make this system much
cheaper than horse traction.

It is well known that we can discharge the storage battery _ad
libitum_ at the rate of 2 amperes or 200 amperes. I can get out of a
storage battery almost any horse power I like for a short space of
time. I have not the least objection to the direct system. But when
you come to run twenty or thirty or fifty cars on one line, you will
require very large conductors or dangerously high electromotive force.
The overhead system is applicable to its own particular purposes.
Where there are only five or ten, or even twenty, cars running on one
line, and that line runs through a suburb or a part of a city where
there are not many houses, that system is to be preferred. The
objection to the overhead system is not so much the want of beauty,
but the want of practicability. You have to put your posts very high
indeed, so as to let great wagon loads of hay and all sorts of things
pass underneath. Most of the trouble comes in winter, and when it is
snowing hard a great many difficulties arise. As regards the loss,
suppose that the resistance of the overhead lines is one ohm. To draw
one car it will take an average of 20 amperes, and the only loss will
be 20 multiplied by 20, that is, 400 watts through line resistance.
But if there are ten cars on that line, you get 40,000 watts loss of
energy, unless you increase the conductor in proportion to the number
of cars. If you do that, you get an enormous conductor, and have a
sort of elevated railroad instead of a telegraph wire, as most people
imagine an overhead conductor to be.

The current required to run a street car is about thirty amperes, and
an electromotive force of about 180 volts. If cars are run in
connection with an incandescent light station, we can arrange our
apparatus so that we can use an E.M.F. say of 110 volts, and then we
can put in a smaller number of cells with a larger capacity that will
give a corresponding horse power. We can charge such larger cells with
50 or 60 amperes instead of thirty.

In regard to arc lighting machinery, the arc lighting dynamo should
not be used to charge the accumulators. They can be used, but they
require such constant attention as to make them impracticable. We can
only use shunt-wound dynamos conveniently for that purpose.

In regard to using two motors on a car, there are several advantages
in it. I use two motors on all my cars in Europe, and always have done
so from the beginning. One of the advantages is that in case of an
accident to one motor the other will bring the car home; secondly,
with two motors we can vary the speed without changing the E.M.F. of
the battery. If I want very much power, I put two motors in parallel,
getting four times the power that I do with one machine, and an
intermediate power of two motors.

There is another advantage of having two motors, and that is that we
can use two driving axles instead of one, and we can go up grades with
almost double the facility that way, because the adhesion would be
double. These are the main advantages arising from the use of two or
more motors.

Mr. Mailloux asked if I would give my experience in regard to the
mechanical transmission between the motor and the car axle. I have
used almost everything that was known at the time, but in order to
give you a full and detailed account of the various modes of
transmission which I have used I should have to give you figures to
bear out certain experiments. I should only be able to do that in a
lecture of at least five hours' duration, so I hope that you will
kindly excuse me on that point.

With regard to the durability of plates, I have taken into
consideration fifteen hours a day. In regard to the application of
electrical brakes, I will say that that was one of the first ideas
that entered my head when I began to use electric motors, and other
people had that idea long before me. I have used an electric brake,
using the motor itself as a brake--that is, as the car runs down a
grade by momentum, it generates a current, but this current cannot be
used for recharging a battery. It is utter nonsense to talk about that
unless we have a steady grade four or five miles long. The advantages
are very small indeed, and the complications which would be introduced
by employing automatic cut-outs, governors, and so on, would
counterbalance anything that might be gained. As regards going up an
incline, of course stopping and starting again has to be done often,
and anybody who at any time works cars by electricity, whether they
have storage batteries or not, has to allow for sufficient motive
power to overcome all the difficulties that any line might present.

One of the great mistakes which some of the pioneers in this direction
made was that they did not put sufficient power upon the cars. You
always ought to put on the cars power capable of exerting perhaps 20
to 40 per cent. more than is necessary in the ordinary street service,
so that in case of the road being snowed up, or in the case of any
other accident which is liable to occur, you ought to have plenty of
power to get out of the scrape.

       *       *       *       *       *


[Illustration: BRISTOL CATHEDRAL.]

An Augustinian monastery, founded by Robert Fitzhardinge in 1142, had
its church, of Norman architecture, to which additions were made in
the early English period. When Edmund Knowle was abbot, from 1306 to
1332, the Norman choir was replaced by that which now exists. His
successor, Abbot Snow, built the chapels on the south side of the
choir. Abbot Newland, between 1481 and 1515, enriched the transepts
with a groined roof and with ornamental work of the decorated Gothic
style, and erected the central tower. Abbot Elliott, who followed
Newland, removed the Norman nave and aisles, intending to rebuild
them; but this was prevented by his death in 1526 and by the
dissolution of the monastery a few years afterward; he completed,
however, the vaulting of the south transept. The church remained with
a nave, and otherwise incomplete, until the modern restorations; after
which, in 1877, it was reopened with a special service. Messrs. Pope &
Bindon, of Bristol, were the architects employed. The exterior, of
which we give an illustration, viewed from St. Augustine's Green, or
Upper College Green, is not very imposing; from the Lower Green there
is a good view of the central tower and the transept. The height of
the tower is but 127 ft. It is of perpendicular Gothic architecture,
but the piers supporting it are Norman. The interior presents many
features of interest. The clustered triple shafts of the piers in the
choir, with their capitals of graceful foliage, the lofty pointed
arches between them, and the groined vaulting, have much beauty. The
chancel is decorated with tracery of a peculiar pattern.

The Abbey of St. Augustine at Bristol was surrendered to King Henry
VIII. in 1538, and became, in 1542, the cathedral of the new Episcopal
see then created. The first Bishop of Bristol, Paul Bush, was deprived
of his see by Queen Mary, being a married clergyman and refusing to
part with his wife. Bishop Fletcher, in Queen Elizabeth's time,
afterward Bishop of Worcester and of London, was twice married, at
which this queen likewise expressed her displeasure. He was father of
Fletcher, the dramatic poet; and he is said to have been one of the
first English smokers of tobacco. Among noted Bishops of Bristol were
Bishop Lake, afterward of Chichester, and Bishop Trelawny (Sir
Jonathan Trelawny, Bart., of Cornwall), two of the "seven bishops";
imprisoned for disobeying an illegal order of James II. "And shall
Trelawny die? Then twenty thousand Cornishmen will know the reason
why." But the most eminent was Bishop Joseph Butler, the author of
"The Analogy of Natural and Revealed Religion" and of the "Sermons on
Human Nature." He was born at Wantage, in Berkshire, and was educated
as a Nonconformist. He was Bishop of Bristol from 1738 to 1750, when
he was translated to Durham. In 1836, the see of Bristol was joined
with that of Gloucester; and the Right Rev. Drs. J.H. Monk, O. Baring,
W. Thomson (now Archbishop of York), and C.J. Ellicott have been
Bishops of Gloucester and Bristol.--_Illustrated London News._

       *       *       *       *       *


In the first days of August, two startling announcements reached us
from the United States. They were as follows:

(1.) "The commander of the Cunarder Umbria reports that at 3 o'clock
on July 27, about 1,500 miles from Sandy Hook, the vessel was struck
by a tidal wave 50 ft. high, which swept the decks, carried away a
portion of the bridge and the forward hatch, and flooded the cabins
and steerage."

(2.) "The captain of the Wilson line steamer Martello reports that at
half-past 8 on the evening of July 25, when in lat. 49° 3' N., long.
31° W., an enormous wave struck the vessel, completely submerging the

In view of these reports, and inasmuch as questions were asked on the
subject in Parliament, though it is quite possible that, as regards
the "tidal" character of the waves, there may be something of
newspaper _gobemoucherie_ in the announcements, we offer a few remarks
on _waves_ in general, which may be useful to some of our readers.

_Tidal phenomena_ present themselves under two aspects: as alternate
elevations and depressions of the sea and as recurrent inflows and
outflows of streams. Careful writers, however, use the word _tide_ in
strict reference to the _changes of elevation_ in the water, while
they distinguish the recurrent streams as _tidal currents_. Hence,
also, _rise_ and _fall_ appertain to the tide, while _flood_ and _ebb_
refer to the tidal current.

The _cause of the tides_ is the combined action of the sun and moon.
The relative effects of these two bodies on the oceanic waters are
directly as their mass and inversely as the square of their distance;
but the moon, though small in comparison with the sun, is so much
nearer to the earth that she exerts the greater influence in the
production of the great _tide wave_. Thus the mean force of the moon,
as compared with that of the sun, is as 2¼ to 1.

The attractive force of the moon is most strongly felt by those parts
of the ocean over which she is vertical, and they are, consequently,
drawn toward her. In the same manner, the influence of the luminary
being less powerfully exerted on the waters furthest from her than on
the earth itself, they must remain behind. By these means, at the two
opposite sides of the earth, in the direction of the straight line
between the centers of the earth and moon, the waters are
simultaneously raised above their mean level; and the moon, in her
progressive westerly motion, as she comes to each meridian in
succession, causes two uprisings of the water--two high tides--the one
when she passes the meridian above, the other when she crosses it
below; and this is done, not by drawing after her the water first
raised, but by raising continually that under her at the time; this is
the _tide wave_. In a similar manner (from causes already referred to)
the sun produces two tides of much smaller dimensions, and the joint
effect of the action of the two luminaries is this, that instead of
four separate tides resulting from their separate influence, the _sun
merely alters the form of the wave raised by the moon_; or, in other
words, the greater of the two waves (which is due to the moon) is
modified in its height by the smaller (sun's) wave. When the summit of
the two happens to coincide, the summit of the combined wave will be
at the highest. When the hollow of the smaller wave coincides with the
summit of the larger, the summit of the combined wave will be at the

It is necessary to have a clear and distinct conception of the
difference between the _motion_ of a _wave_ and that of a _current_.
In the current there is a transfer of water; in the wave the transfer
is no more than would be brought about by a particle of water
impinging on another where that particle has a motion perpendicular to
the surface, and a rising and falling results. The onward movement of
the wave itself is always perceptible enough. That the water is not
moving with the same velocity is also evident from watching the
progress of any light body floating on its surface. This fact may be
practically illustrated in the case of a ship at sea, sailing before
the wind in the same direction as the waves are moving. When the crest
of a wave is near the stern, drop a piece of wood on it. Almost
instantly the wave will be seen shooting ahead of the vessel, while
the wood is scarcely removed from the position where it fell on the
water. The wave has moved onward, preserving its identity as a wave,
the water of which it is formed being constantly changed; and thus the
motion of the wave is one thing, that of the water in which the waves
are formed is quite another thing.

Again, waves are formed by a force acting horizontally; but in the
case of the tide wave, that force acts uniformly from the surface to
the lowest depths of the ocean, and the breadth of the wave is that
curved surface which, commencing at low water, passes over the summit
of the tide down to the next low water--this is a wave of the first
order. In waves of the second order, the force raising them acts only
on the surface, and there the effect is greatest (as in the wind
waves)--where one assists in giving to the water oscillating motion
which maintains the next, and gradually puts the whole surface in
commotion; but at a short distance down that effect entirely

If the earth presented a uniform globe, with a belt of sea of great
and uniform depth encircling it round the equator, the tide wave would
be perfectly regular and uniform. Its velocity, where the water was
deep and free to follow the two luminaries, would be 1,000 miles an
hour, and the height of tide inconsiderable. But even the Atlantic is
not broad enough for the formation of a powerful tide wave. The
continents, the variation in the direction of the coast line, the
different depths of the ocean, the narrowness of channels, all
interfere to modify it. At first it is affected with only a slight
current motion toward the west--a motion which only acquires strength
when the wave is heaped up, as it were, by obstacles to its progress,
as happens to it over the shallow parts of the sea, on the coasts, in
gulfs, and in the mouths of rivers. Thus the first wave advancing
meets in its course with resistance on the two sides of a narrow
channel, it is forced to rise by the pressure of the following waves,
whose motion is not at all retarded, or certainly less so than that of
the first wave. Thus an actual current of water is produced in straits
and narrow channels; and it is always important to distinguish between
the tide wave, as bringing high water, and the tidal stream--between
the rise and fall of the tide and the flow and ebb.

In the open ocean, and at a distance from the land, the tide wave is
imperceptible, and the rise and fall of the water is small. Among the
islands of the Pacific four to six feet is the usual spring rise. But
the range is considerably affected by local causes, as by the shoaling
of the water and the narrowing of the channel, or by the channel
opening to the free entrance of the tide wave. In such cases the range
of tide is 40 to 50 feet or more, and the tidal stream is one of great
velocity. It may under such circumstances even present the peculiar
phenomenon called the _bore_--a wave that comes rolling in with the
first of flood, and, with a foaming crest, rushes onward, threatening
destruction to shipping, and sweeping away all impediments lying in
its course.

It is certain that in the open ocean the _great tide wave_ could not
be recognized as a wave, since it is merely a temporary alteration of
the sea level.

_Waves_ which have their origin in the action of the wind striking the
surface of the water commence as a series of small and slow
undulations or wavelets--a mere ripple. As the strength, and
consequently the pressure, of the wind increases, waves are formed;
and a numerical relation exists between the length of a wave, its
velocity of progress, and the depth of the water in which it travels.

The _height_ of a wave is measured from trough to crest; and though
waves as seen from the deck of a small vessel appear to be "enormous"
and "overwhelming," their height, in an ordinary gale, in deep water,
does not exceed 15 to 20 feet. In a very heavy gale of some days'
continuance they will, of course, be much higher.

Scoresby has observed them 30 ft. high in the North Atlantic; and Ross
measured waves of 22 ft. in the South Atlantic. Wilkes records 32 ft.
in the Pacific. But the highest waves have been reported off the Cape
of Good Hope and Cape Horn, where they have been observed, on rare
occasions, from 30 to 40 ft high; and 36 ft. has been given as the
admeasurement in the Bay of Biscay, under very exceptional
circumstances. In the voyage round the world the Venus and Bonite
record a maximum of 27 ft., while the Novara found the maximum to be
35 ft. But waves of 12 to 14 ft. in shallow seas are often more trying
than those of larger dimensions in deeper water. It is generally
assumed that a distance from crest to crest of 150 to 350 ft. in the
storm wave gives a velocity (in the change of form) of from 17 to 28
miles per hour. But what is required in the computation of the
velocity is the period of passage between two crests. Thus a distance
of 500 to 600 ft. between two crests, and a period of 10 to 11
seconds, indicates a velocity of 34 miles per hour.

The following table, by Sir G.B. Airy (late Astronomer Royal), shows
the velocities with which waves of given lengths travel in water of
certain depth:

  Depth of |            Length of the Wave in Feet.[1]
  the Water|     |      |       |        |         |          |
  in Feet. |  10 |  100 | 1,000 | 10,000 | 100,000 |1,000,000 |10,000,000
           | Corresponding Velocity of Wave per Hour in Nautical Miles.
         1 | 3.2 |  3.4 |   3.4 |    3.4 |     3.4 |      3.4 |       3.4
        10 | 4.3 | 10.1 |  10.7 |   10.8 |    10.8 |     10.8 |      10.8
       100 | 4.3 | 13.5 |  32.0 |   34.0 |    34.0 |     34.0 |      34.0
     1,000 | 4.3 | 13.5 |  42.9 |  101.8 |   107.5 |    107.5 |     107.5
    10,000 | 4.3 | 13.5 |  42.9 |  135.7 |   320.3 |    340.0 |     340.3
   100,000 | 4.3 | 13.5 |  42.9 |  135.7 |   429.3 |   1013.0 |    1075.3

  [Footnote 1: As an example, this table shows that waves 1,000 feet
  in length travel 43 nautical miles per hour in water 1,000 feet
  deep. The length is measured from crest to crest.]

From these numbers it appears that--

1. When the length of the wave is not greater than the depth of the
water, the velocity of the wave depends (sensibly) only on its length,
and is proportional to the square root of its length.

2. When the length of the wave is not less than a thousand times the
depth of the water, the velocity of the wave depends (sensibly) only
on the depth, and is proportional to the square root of the depth.

It is, in fact, the same as the velocity which a free body would
acquire by falling from rest under the action of gravity through a
height equal to half the depth of the water.

_Rollers_ are of the nature of a violent _ground swell_, and possibly
the worst of them may be due to the propagation of an earthquake wave.
They come with little notice, and rarely last long. All the small
islands in the Mid-Atlantic experience them, and they are frequent on
the African coast in the calm season. They are also not unknown in the
other oceans. In discussing the meteorology of the equatorial district
of the Atlantic, extending from lat. 20° to 10° S, Captain Toynbee
observes that "swells of the sea are not always caused by the
prevailing wind of the neighborhood. For instance, during the northern
winter and spring months, northwesterly swells abound. They are
sometimes long and heavy, and extend to the most southern limit of the
district. Again, during the southern winter and spring months,
southerly and southwesterly swells abound, extending at times to the
most northern limit of the district. They are frequently very heavy
and long."

The great _forced sea waves_, due to earthquakes, and generally to
subterranean and volcanic action, have been known to attain the
enormous height of 60 feet or more, and sweep to destruction whole
towns situated on the shores where they have broken--as for example
Lisbon and places on the west coast of America and in the island of
Java. Though so destructive when they come in toward the land, and
begin to feel the shelving sea bottom, it is not probable that, in the
open ocean, this wave would do more than appear as a long rolling
swell. It has, however, been observed that "a wave with a gentle front
has probably been produced by gentle rise or fall of a part of the sea
bottom, while a wave with a steep front has probably been due to a
somewhat sudden elevation or depression. Waves of complicated surface
form again would indicate violent oscillations of the bottom."

The altitude and volume of the great sea wave resulting from an
earthquake depend upon the suddenness and extent of the originating
disturbance and upon the depth of water at its origin. Its velocity of
translation at the surface of the sea varies with the depth of the sea
at any given point, and its form and dimensions depend upon this also,
as well as upon the sort of sea room it has to move in. In deep ocean
water, one of these waves may be so long and low as to pass under a
ship without being observed, but, as it approaches a sloping shore,
its advancing slope becomes steeper, and when the depth of water
becomes less than the altitude of the wave, it topples over, and comes
ashore as an enormous and overwhelming breaker.

Lastly, there is the _storm wave_--the result of the cyclone or
hurricane--and, perhaps, the greatest terror to seamen, for it almost
always appears in the character of a _heavy cross sea_, the period of
which is irregular and uncertain. The disturbance within the area of
the cyclone is not confined to the air, but extends also to the ocean,
producing first a rolling swell, which eventually culminates in a
tremendous pyramidal sea and a series of storm waves, the undulations
of which are propagated to an extraordinary distance, behind, before,
and on each side of the storm field.

Enough has now been said to show that whatever the character of the
waves encountered by the Umbria and Martello in July last, they were
in no sense "tidal," but, if approximating to the dimensions stated,
they were either due to storm or earthquake, or, possibly, to a
combination of both the last agents.

For those of our readers who may be interested in wave observations,
we conclude by introducing Prof. Stokes' summary of the method of
observing the phenomenon:

          "_For a Ship at Sea._

    "(1.) The apparent periodic time,[2] observed as if the ship
    were at rest.

    "(2.) The _true_ direction from which the waves come, also the
    ship's _true_ course and speed per hour.

    "(3.) A measure or estimate of the height of the waves.

    "(4.) The depth of the sea if it is known, but, at any rate,
    the position of the ship as near as possible, either by cross
    bearings of land or any other method, so that the depth may be
    got from charts or other sources.

          "_For a Ship at Anchor._

    "(1.) The periodic time.

    "(2.) The true direction from which the waves come.

    "(3.) A measure or estimate of the height of the waves.

    "(4.) The depth of water where she is anchored."

  [Footnote 2: The period of a wave is the interval of time which
  elapses between the transits of two successive wave crests past a
  stationary floating body, the wave crest being the highest line
  along the ridge.]

It is the opinion of scientists that when the period of oscillation of
the ship and the period of the wave are nearly the same, the turning
over of the ship is an approximate consequence, and thus the wave to
such a ship would appear more formidable than to another ship with a
different period of oscillation.--_Nautical Magazine._

       *       *       *       *       *


It is now recognized that one of the elements in which the public
school systems of the United States are most lacking is in the
practical branches in teaching trades and industry. There is too much
book learning, too little practical education. Throughout the
continent of Europe there are trade and industrial schools which have
accomplished much in turning out skilled workmen for the various
branches of industry. Here we have one. Our deficiency in this matter
was recognized by the late commissioner of education, and attention
called to it in several of his reports, and a number of the State
superintendents of education have also urged the establishment of
manual or training schools as a part of the State systems. We have
such an institution here in the Tulane Manual School. In Philadelphia,
Cleveland, and Chicago, the system has been adopted on a large scale,
and made part of the high school course. Another city which has
inaugurated the manual training school as a part of its public schools
is Toledo, O. A rich citizen of that town, who recently died, left a
large sum for the establishment of a university of arts and trades.
Instead of founding a separate university, however, the money was
applied to the establishment of manual schools in connection with the
public schools, for both boys and girls.

The course of girls' work given will afford some idea of what it is
proposed to do. This begins with the senior grammar school grade and
continues three years in high school. It includes free hand,
mechanical, and architectural drawing, light carpentry, wood carving,
designing for wood carving, wood turning, clay moulding, decorative
designing, etc. But more practical than these things are the lessons
in cooking, sewing, and household management. The course in domestic
economy "is arranged with special reference to giving young women such
a liberal and practical education as will inspire them with a belief
in the dignity and nobleness of an earnest womanhood, and incite them
to a faithful performance of the every day duties of life. It is based
upon the assumption that a pleasant home is an essential element of
broad culture, and one of the surest safeguards of morality and
virtue." The report of the school also remarks that "the design of
this course is to furnish thorough instruction in applied
housekeeping, and the sciences related thereto, and students will
receive practical drill in all branches of housework; in the purchase
and care of family supplies, and in general household management; but
will not be expected to perform more labor than is actually necessary
for the desired instruction."

A special branch which will be well received is that which proposes to
teach the girls how to cook. The curriculum is one that every
housekeeper ought to go through.

Boiling--Practical illustrations of boiling and steaming, and
treatment of vegetables, meats, fish, and cereals, soup making, etc.

Broiling--Lessons and practice in meat, chicken, fish, oysters, etc.

Bread Making--Chemical and mechanical action of materials used.
Manipulations in bread making in its various departments. Yeasts and
their substitutes.

Baking--Heat in its action on different materials in the process of
baking. Practical experiments in baking bread, pastry, puddings,
cakes, meat, fish, etc.

Frying--Chemical and mechanical principles involved and illustrated in
the frying of vegetables, meats, fish, oysters, etc.

Mixing--The art of making combinations, as in soups, salads, puddings,
pies, cakes, sauces, dressings, flavorings, condiments, etc.

In "marketing, economy," etc., the course comprises general teaching
on the following subjects:

    "The selection and purchase of household supplies. General
    instructions in systematizing and economizing the household
    work and expenses. The anatomy of animals used as food, and
    how to choose the several parts. Lessons on the qualities of
    water and steam; the construction of stoves and ranges; the
    properties of different fuels."

Again, there is a dressmaking and millinery department, where the
girls are taught how to cut and make dresses and other garments, and
the economical and tasteful use of materials.

So much for the girls. The courses in the boys' schools are somewhat
similar, turning, however, on the more practical instruction in trades
and industries, in carpentering, wood and iron work, etc.

The Toledo experiment has been tried there but one year, and has given
general satisfaction. The board of school directors has interested the
public in its efforts, and advisory committees of ladies and gentlemen
have been appointed to assist in managing these schools.

It is to be hoped that other and larger cities will imitate Toledo in
the matter. Those philanthropists who are giving money so liberally
for the establishment of institutions of higher learning might do much
good in providing for manual training schools of this kind that will
assure the country good housewives and skilled mechanics in the
future.--_Trustees' T. Jour._

       *       *       *       *       *


When it was announced in the _Lumberman_ that the barge Wahnapitæ had
carried a cargo of 2,181,000 feet of lumber, letters were received
asking if it was not a typographical error. It was thought by many
that no boat could carry such a load. For the purpose of showing the
barge on paper, a photograph was obtained of her when loaded at
Duluth, which is herewith reproduced. The freight rate obtained to
Tonawanda was $3.75 a thousand, which footed up to a total of
$8,178.75 The owners of the boat, however, were not satisfied with
such a record, and proceeded to break it by loading at Duluth
2,409,800 feet of lumber, which also went to Tonawanda, and which is
put down as the biggest cargo of lumber on record. At the latter place
the cargo was unloaded on Saturday afternoon and Monday forenoon--one
working day. It will be readily understood that the money-making
capacity of the barge is of the Jumbo order also.


The barge is owned by the Saginaw Lumber and Salt Company and the
Emery Lumber Company, and cost $30,000. She is 275 feet long and 51
feet beam. The lumber on her was piled 22 feet high and she drew 11
feet of water. Had she been 10 inches wider, she could not have passed
through the Soo canal. The boat was built on the Saginaw river a year
ago last winter, and was designed for carrying logs from the Georgian
bay to the Saginaw river and Tawas mills. The Canadian government,
however, increased the export duty on logs, and the barge was put into
the lumber-carrying trade--_N.W. Lumberman._

       *       *       *       *       *


The process of extracting gold from ores by absorption of the precious
metal in chlorine gas, from which it is reduced to a metallic state,
is not a very new discovery. It was first introduced by Plattner many
years ago, and at that time promised to revolutionize the processes
for gold extraction. By degrees it was found that only a very clever
chemist could work this process with practically perfect results, for
many reasons. Lime and magnesia might be contained in the quartz, and
would be attacked by the chlorine. These consume the reagents without
producing any results, earthy particles would settle and surround the
small gold and prevent chlorination, then lead and zinc or other
metals in combination with the gold would also be absorbed by the
chlorine; or, again, from some locally chemical peculiarity in the
water or the ore, gold held in solution by the water might be again
precipitated in the tailings before filtration was complete, and thus
be lost. Henderson, Clark, De Lacy, Mears, and Deacon, all introduced
improvements, or what were claimed to be improvements, on Plattner,
but these chiefly failed because they did not cover every particular
variety of case which gold extraction presented. Therefore, where
delicate chemical operations were necessary for success, practice
generally failed from want of knowledge on the part of the operator,
and many times extensive plants have been pronounced useless from this
cause alone. Hence it is not to be wondered that processes requiring
such care and uncommon knowledge are not greatly in favor.

Mr. Claude Vautin, a gentleman possessed of much practical experience
of gold mining and extraction in Queensland, together with Mr. J.
Cosmo Newbery, analytical chemist to the government of Victoria, have
developed a process which they claim to combine all the advantages of
the foregoing methods, and by the addition of certain improvements in
the machinery and mode of treatment to overcome the difficulties which
have hitherto prevented the general adoption of the chlorination

By reference to the illustrations of the plant below, the system by
which the ore is treated can be readily understood. The materials for
treatment--crushed and roasted ore, or tailings, as the case may
be--are put into the hopper above the revolving barrel, or
chlorinator. This latter is made of iron, lined with wood and lead,
and sufficiently strong to bear a pressure of 100 lb. to the square
inch, its capacity being about 30 cwt of ore. The charge falls from
the hopper into the chlorinator. Water and chlorine-producing
chemicals are added--generally sulphuric acid and chloride of
lime--the manhole cover is replaced and screwed down so as to be gas
tight. On the opposite side of the barrel there is a valve connected
with an air pump, through which air to about the pressure of four
atmospheres is pumped in, to liquefy the chlorine gas that is
generated, after which the valve is screwed down. The barrel is then
set revolving at about ten revolutions a minute, the power being
transmitted by a friction wheel. According to the nature of the ore,
or the size of the grains of gold, this movement is continued from one
to four hours, during which time the gold, from combination with the
chlorine gas, has formed a soluble gold chloride, which has all been
taken up by the water in the barrel. The chlorinator is then stopped,
and the gas and compressed air allowed to escape from the valve
through a rubber hose into a vat of lime water. This is to prevent the
inhalation of any chlorine gas by the workmen. The manhole cover is
now removed and the barrel again set revolving, by which means the
contents are thrown automatically into the filter below. This filter
is an iron vat lined with lead. It has a false bottom, to which is
connected a pipe from a vacuum pump working intermittently. As soon as
all the ore has fallen from the chlorinator into the filter, the pump
is set going, a partial vacuum is produced in the chamber below the
false bottom in the filter, and very rapid filtration results. By this
means all the gold chlorides contained in the wet ore may be washed
out, a continual stream being passed through it while filtration is
going on. The solution running from the filter is continually tested,
and when found free from gold, the stream of water is stopped, as is
also the vacuum pump. The filter is then tipped up into a truck below,
and the tailings run out to the waste heap. The process of washing and
filtration occupies about an hour, during which time another charge
may be in process of treatment in the chlorinator above. The discharge
from the filter and the washings are run into a vat, and from this
they are allowed to pass slowly through a tap into a charcoal filter.
During the passage of the liquid through the charcoal filter, the
chloride of gold is decomposed and the gold is deposited on the
charcoal, which, when fully charged, is burnt, the ashes are fused
with borax in a crucible, and the gold is obtained.


We have specified above the objections to the old processes of
chlorination, so it may be fairly asked in what way the Newbery-Vautin
process avoids the various chemical actions which have hitherto proved
so difficult to contend with.

For any system of chlorination yet introduced it is necessary to free
the ore from sulphides. This is done by roasting according to any of
the well-known systems in vogue. It is a matter which requires great
care and considerable skill. The heat must be applied and increased
slowly and steadily. If, through any neglect on the part of the
roaster, the ore is allowed to fuse, in most cases it is best to throw
the charge away, as waste. This roasting applies equally to the Vautin
process as to any others. So on this head there is no alteration. One
of the most important advantages is not a chemical one, but is the
rapidity with which the charge can be treated. In the older styles of
treatment the time varied from thirty six to ninety hours. Now this is
accomplished in from three to six hours with a practically perfect
result. The older processes required a careful damping of the ore,
which, to get good results, must leave the ore neither too wet nor too
dry. Now "damping" is entirely done away with, and in its place water
is poured into the barrel. Pressure to the extent of four atmospheres
causes chlorine gas to leave its vaporous form. Thus the pressure
applied not only enables a strong solution of chlorine to be formed
with the water in the barrel, but forces this into contact with the
gold through every crevice in the ore. Chlorine gas also takes up any
silver which may exist in association with the gold. In the older
processes this is deposited as a film of chloride of silver around the
fine gold grains, and from its insolubility in water prevents the
absorption of the gold. The rotary motion of the barrel in the
Newbery-Vautin method counteracts this by continually rubbing the
particles together; this frees the particles from any accumulations,
so that they always present fresh surfaces for the action of the
solvent. Again, the short time the ore is in contact with the chlorine
does not allow of the formation of hydrochloric acid, which has a
tendency to precipitate the gold from its soluble form in the water
before being withdrawn from the chlorinator.

Hitherto, when the ore was very fine or contained slimes, the
difficulty of filtration was increased, sometimes in extreme cases to
such an extent that chlorination became impracticable. By the
introduction of the vacuum pump this is greatly facilitated; then by
making the action intermittent a jigging motion is given to the
material in the filter which prevents any clogging except in cases of
extreme fineness.

The advantage of using charcoal as a decomposing agent for chloride of
gold was pointed out by Mr. Newbery some twenty years ago; four or
five years since the idea was patented in the United States, but as
this was given gratis to the world years before, the patent did not
hold good. The form of precipitation generally adopted was to add
sulphate of iron to the liquid drawn from the filter. This not only
threw down the gold it contained, but also the lime and magnesia. Then
very great care was necessary, and a tedious process had to be gone
through to divide the gold from these. Now, by filtration through
charcoal everything that is soluble in hydrochloric acid passes away
with the water; for instance, lime and magnesia, which before gave
such great trouble. In passing through the charcoal, the chloride of
gold is decomposed and all fine gold particles are taken up by the
charcoal, so that it is coated by what appears to be a purple film.

Should copper be associated with the gold, the water, after running
through the charcoal filter, is passed over scrap iron, upon which the
copper is precipitated by a natural chemical action. If silver is
contained in the ore, it is found among the tailings in the filter, in
a chloride which is insoluble in water. Should the quantity prove
sufficiently large, it may be leached out in the usual way by

One of the great advantages common to all systems of chlorination is
that ores may be crushed dry and treated, so that the loss from float
gold may be avoided. Of this loss, which is most serious, we shall
have something to say on another occasion. An advantage in
amalgamation with chlorine gas instead of amalgamation with
quicksilver in the wet way, is that the ore need not be crushed so
finely. Roasting takes the place of fine crushing, as the ore from the
roasting furnace is either found somewhat spongy in texture or the
grains of silica in which fine gold may be incased are split or flawed
by the fire. For quicksilver amalgamation very fine crushing is
necessary to bring all gold particles in contact with it. Quicksilver
being so thick in substance, it will not find its way readily in and
out of a microscopically fine spongy body or through very fine flaws
in grains of silica, whereas chlorine gas or a solution of liquefied
chlorine does this, and absorbs the gold far more readily.

There are cases when gold is contained in ores in what is known as a
perfectly "free" form--that is, there is an absence of all sulphides,
arsenides, etc.--when it is not practicable to extract it either with
the ordinary forms of quicksilver amalgamation of or any process of
chlorination, without first roasting. This is because the finer gold
is locked up inside fine grains of silica and hydrated oxide of iron.
No ordinary crushing will bring this fine enough, but when roasting is
resorted to by drawing it rapidly through a furnace heated to a cherry
red, these grains are split up so that chlorine gas is enabled to
penetrate to the gold.

It may be said that an equally clever chemist will be required to work
this improved process as compared with those that have, one by one,
fallen into disuse, mainly from want of knowledge among the operators.
To a certain extent this is so. The natural chemical actions are not
so delicate, but an ignorant operator would spoil this process, as he
does nearly every other. When a reef is discovered, practice shows
that its strongest characteristics are consistently carried throughout
it wherever it bears gold. Before Messrs. Newbery and Vautin leave a
purchaser to deal himself with their process, they get large samples
of his ore to their works and there experiment continually until a
practically perfect result is obtained; then any one with a moderate
amount of knowledge can work with the formula supplied. It has been
their experience that the ore from any two mines rarely presents the
same characteristics. Experiments are begun by treating very coarse
crushings. These, if not satisfactory, are gradually reduced until the
desired result is obtained.

To treat the whole body of ore from a mine, dry crushing is strongly
recommended. To accomplish this in the most efficient manner, a stone
breaker which will reduce to about ¼ in. cubes is necessary. For
subsequent crushing Kroms rolls have, up to the present time, proved
most satisfactory. They will crush with considerable evenness to a
thirty mesh, which is generally sufficient. The crushings are then
roasted in the ordinary way in a reverberatory furnace and the whole
of the roastings are passed through the machine we have just
described. By this it is claimed that over 90 per cent. of the gold
can be extracted at very much the same cost as the processes now in
general use in gold producing countries, which on the average barely
return 50 per cent. If so, the gentlemen who have brought forward
these improvements deserve all the success their process

       *       *       *       *       *


The apparatus herewith illustrated consists of a wooden base, which
may be bolted to the floor, and which supports two wooden uprights, to
which is affixed the apparatus designed to exercise the legs. The
apparatus for exercising the arms is mounted upon a second frame that
slides up and down the wooden supports. It is fixed in position at any
height by means of two screws.


The apparatus for exercising the legs, as well as the one for the
arms, consists essentially of a fly wheel mounted upon an axle
extending to the second upright and bent into the form of a crank in
the center. The fly wheel is provided with a winch whose arm is
capable of elongation in order to accommodate it to the reach of the
sound limb.

The apparatus for the legs is arranged in a contrary direction, that
is to say, the wheel is on the opposite side of the frame, and upon
the fixed uprights. It is really a velocipede, one of the pedals of
which is movable upon the winch, and is capable of running from the
axle to the extremity, as in the upper apparatus. This pedal has the
form of a shoe, and is provided with two straps to keep the foot in
place and cause it to follow the pedal in its rotary motion. A movable
seat, capable of rising and descending and moving backward and
forward, according to the leg that needs treatment, is fixed back of
the apparatus.

The operation is as follows: Suppose that the atrophied arm is the
left one. The invalid, facing the apparatus, grasps the movable handle
on the crank with his left hand, and revolves the winch with his
right. The left hand being thus carried along, the arm is submitted to
a motion that obliges it to elongate and contract alternately, and the
result is an extension of the muscles which strengthens them.

The apparatus, which is as simple as it is ingenious, can, it is true,
be applied only when one of the two limbs, arm or leg, is diseased,
the other being always necessary to set the apparatus in motion; but,
even reduced to such conditions, it is destined to render numerous
services in cases of paralysis, atrophy, contusions, etc.--_Moniteur
des Inventions Industrielles._

       *       *       *       *       *


Dr. Javal has just presented to the Academy of Medicine a very
ingenious and practical optometer devised by George J. Bull, a young
American doctor, after a number of researches made at the laboratory
of ophthalmology at the Sorbonne. Among other applications that can be
made of it, there is one that is quite original and that will insure
it some success in the world. It permits, in fact, of approximately
deducing the age of a person from certain data that it furnishes as to
his or her sight. As well known, the organs become weak with age,
their functions are accomplished with less regularity and precision,
and, according to the expression of the poet,

  "_En marchant a la mort, on meurt a chaque pas,_"

the senses become blunted, the hearing becomes dull, the eyes lose
their luster, vivacity, and strength, and vision becomes in general
shorter, less piercing, and less powerful.

The various parts of the eye, but more particularly the crystalline
lens, undergo modifications in form and structure. Accommodation is
effected with more and more difficulty, and, toward the age of sixty,
it can hardly be effected at all.

These changes occur in emmetropics as well as in hypermetropics and

As will be seen, then, there is a relation between the age of a
person and the amplitude of the accommodation of his eyes. If we
cannot express a law, we can at least, through statistics, find out,
approximately, the age of a person if we know the extent of the
accommodation of his eyes.

A Dutch oculist, Donders, has got up a table in which, opposite the
amplitudes, the corresponding ages are found. Now, the Javal-Bull
optometer permits of a quick determination of the value of the
amplitude of accommodation in _dioptries_. (A dioptrie is the power of
a lens whose focal distance is one meter.)

The first idea of this apparatus is due to the illustrious physicist
Thomas Young, who flourished about a century ago. The Young apparatus
is now a scarcely known scientific curiosity that Messrs. Javal and
Bull have resuscitated and transformed and completed.

It consists of a light wooden rule about 24 inches long by 1¼ inch
wide that can easily be held in the hand by means of a handle fixed at
right angles with the flat part (Fig. 1). At one extremity there is a
square thin piece of metal of the width of the rule, and at right
angles with the latter, but on the side opposite the handle. This
piece of metal contains a circular aperture a few hundredths of an
inch in diameter (Fig. 3). Toward this aperture there may be moved
either a converging lens of five dioptries or a diverging lens of the
same diameter, but of six dioptries.


On holding the apparatus by the handle and putting the eye to the
aperture, provided or not with a lens, we see a series of dominoes
extending along the rule, from the double ace, which occupies the
extremity most distant from the eye, to the double six, which is very
near the eye (Fig. 2). The numbers from two to twelve, simply, are
indicated, but this original means of representing them has been
chosen in order to call attention to them better.

[Illustration: FIG 2.--THE RULE, WITH THE DOMINOES (¼ Actual
Size.) ]

Figures are characters without physiognomy, if we may so express
ourselves, while the spots on the dominoes take particular
arrangements according to the number represented, and differentiate
themselves more clearly from each other than figures do. They are at
the same time more easily read than figures or regularly spaced dots.
Now, it is very important to fix the attention upon the numbers, since
they are arranged at distances expressed in dioptries and indicated by
the number of the spots. On looking through the aperture, we see in
the first place one of the dominoes more distinctly than the rest.
Then, on endeavoring to see those that are nearer or farther off, we
succeed in accommodating the eye and in seeing the numbers that
express the extreme terms of the accommodation, and consequently the

[Illustration: FIG. 3.--DETAILS OF EYE PIECE.]

Let us now take some examples: If we wish to express in dioptries the
myopia of a person, we put the apparatus in his hand, and ask him to
place his eye very near the aperture and note the number of spots on
the most distant domino that he sees distinctly. This is the number
sought. If the observation be made through the upper lens, it will be
necessary to subtract five from the number obtained; if, on the
contrary, the other lens is used, it will be necessary to add six.

If it is a question of a presbyope, let him look with his spectacles,
and note the nearest domino seen distinctly. This will be the number
of dioptries expressing the nearest point at which he can read. This
number permits us to know whether it is necessary to add or subtract
dioptries in order to allow him to read nearer by or farther off. If,
for example, he sees the deuce and the ace distinctly, say 3 dioptries
or 0.33 meter, and we want to allow him to read at 0.25 meter,
corresponding to four dioptries, it will be necessary to increase the
power of his spectacles by one dioptrie.

Upon the whole, Dr. Bull's optometer permits of measuring the
amplitude of accommodation, and, consequently, of obtaining the
approximate age of people, of knowing the extreme distances of the
accommodation, and of quickly finding the number of the glass
necessary for each one. It reveals the defects in the accommodation,
and serves for the quick determination of refraction. So, in saying
that this little instrument is very ingenious and very practical, Dr.
Javal has used no exaggeration.--_La Nature._

       *       *       *       *       *


  [Footnote 1: Abstract from the presidential address delivered
  before the Association of Municipal and Sanitary Engineers and
  Surveyors, at the annual meeting in Leicester, July 18, 1887.]

By Mr. J. GORDON, C.E.

The average mortality for England and Wales was 22.4 in 1838, and in
1886 19.3, which shows a saving on last year's population of England
and Wales of 86,400 lives annually, and a saving in suffering from an
estimated number of about 1,728,000 cases of sickness. To accomplish
all this, vast sums of money have been expended, probably not always
wisely, inasmuch as there have been mistakes made in this direction,
as in all new developments of science when applied in practice, and
evils have arisen which, if foreseen at all at the outset, were

The great object of the public health act, 1848, was to enable local
authorities by its adoption to properly sewer, drain, and cleanse
their towns, and to provide efficient supplies of water, free from
contamination and impurities dangerous to health. The raising of money
by loans repayable in a series of years, which the act empowered,
enabled all these objects to be accomplished, and, while the first
duty of local authorities was undoubtedly the provision of a good
supply of water and proper sewerage for the removal of liquid filth
from the immediate vicinity of inhabited dwellings, the carrying out
of proper works for the latter object has been of much slower growth
than the former. Private companies led the way, in fact, in providing
supplies of water, inasmuch as there was a prospect of the works
becoming remunerative to shareholders investing their money in them;
and in nearly every instance where local authorities have eventually
found it to be in the interests of the inhabitants of their districts
to purchase the work, they have had to pay high prices for the
undertaking. This has generally led to a great deal of dissatisfaction
with companies holding such works, but it must not be forgotten that
the companies would, in most instances, never have had any existence
if the local authorities had taken the initiative, and that but for
the companies this great boon of a pure supply of water would most
probably have been long delayed to many large as well as small

The evils which have arisen from the sewering and draining of towns
have been of a twofold character. First, in the increased pollution of
rivers and streams into which the sewage, in the earlier stages of
these works, was poured without any previous treatment; and secondly,
in the production of sewer gas, which up to the present moment seems
so difficult to deal with. These concomitant evils and difficulties
attending the execution of sanitary works are in no way to be
underrated, but it still remains the first duty of town authorities to
remove, as quickly as possible, all liquid and other refuse from the
midst and immediate vicinity of large populations, before putrefaction
has had time to take place.

There are some minds whose course of reasoning seems to lead them to
the conclusion that the evils attending the introduction of modern
systems of sewerage are greater than those of the old methods of
dealing with town sewage and refuse, but the facts are against them to
such an extent that it would be difficult to point to a responsible
medical officer in the kingdom who would be courageous enough to
advocate a return to the old regime of cesspools, privy ashpits, open
ditches, and flat bottomed culverts. The introduction of earth closets
as one of the safeguards against sewer gas has made no headway for
large populations, and is beset with practical difficulties.

In the Midland and Lancashire towns the system known as the pail or
tub system has been much more largely introduced as a substitute for
the water closet, and it has, from a landlord's point of view, many
attractions. In the first place, the first cost, as compared with that
of a water closet, is very small, and the landlord is relieved for
ever afterward I believe, in most towns, of all future costs and
maintenance; whereas, in the case of water closets, there is
undoubtedly great difficulty in cottage property in keeping them in
good working order, especially during the frosts of winter. There are,
however, many objections to the pail system, which it is not proposed
to touch upon in this address, beyond this, that it appears to be a
costly appendage to the water carriage system, without the expected
corresponding advantage of relieving the municipal authorities of any
of the difficulties of river pollution, inasmuch as the remaining
liquid refuse of the town has still to be dealt with by the modern
systems of precipitation or irrigation, at practically the same cost
as would have been the case if the water carriage system had been
adopted in its entirety.

The rivers pollution act gave an impetus to works for the treatment of
sewage, although much had been done prior to that, and Leicester was
one of those towns which led the way so early as 1854 in precipitating
the solids of the sewage before allowing it to enter the river. The
innumerable methods which have since then been tried, and after large
expenditures of money have proved to be failures, show the
difficulties of the question.

On the whole, however, sewage farms, or a combination of the chemical
system with irrigation or intermittent filtration, have been the most
successful, so that the first evil to which the cleansing of towns by
the increased pollution of rivers gave rise may now be said to be
capable of satisfactory solution, notwithstanding that the old battle
of the systems of precipitation versus application of sewage to land
still wages whenever opportunity occurs.

The second evil to which I have made reference, viz., that of sewer
ventilation, seems still unsolved, and I would earnestly entreat
members, all of whom have more or less opportunities of experimenting
and making observations of the behavior of sewer gas under certain
conditions, to direct their attention to this subject. It is admitted
on all hands that the sewers must be ventilated--that is, that there
must be a means of escape for the polluted air of the sewers; for it
is well known that the conditions prevailing within the sewers during
the twenty-four hours of the day are very varying, and on this subject
the early observations of the late medical officer for the City of
London (Dr. Letheby), and the present engineer for the City of London
(Lieutenant-Colonel Heywood), and the still more recent investigations
of Professor Pettenkofer, of Munich, Professor Soyka, of Prague, and
our own members, Mr. McKie, of Carlisle, Mr. Read, of Gloucester, and
others, are worthy of attention. It does not, however, seem to be so
readily or universally conceded that a plentiful supply of fresh air
is of equal importance, and that the great aim and object of sewer
ventilation should be the introduction of atmospheric air for the
purpose of diluting and oxidizing the air of the sewers, and the
creation of a current to some exit, which shall, if possible, either
be above the roofs of the houses, or, still better, to some point
where the sewer gas can be cremated. The most recent contribution to
this subject, in direct opposition to these views, is to be found in
the address of Professor Attfield to the Hertfordshire Natural History
Society and Field Club, in which it is laid down that all that is
necessary is a vent at an elevation above the ground, and that,
therefore, the surface ventilators, or other openings for the
introduction of fresh air, are not only not necessary, but are, on the
contrary, injurious, even when acting as downcast shafts.

These aims and objects are beset with difficulties, and the most
scientific minds of the country have failed so far to devise a method
of ventilation which shall at the same time be within the range of
practical application as regards cost and universally satisfactory.

The report of last year of a committee of the metropolitan board of
works is worth attention, as showing the opinion of metropolitan
surveyors. Out of forty districts, the opinions of whose surveyors
were taken, thirty-five were in favor of open ventilation, two were
doubtful, two against, and one had no experience in this matter. The
average distances of the ventilators were from 30 to 200 yards, and
the committee came to the conclusion that "pipe ventilators of large
section can be used with great advantage in addition to, and not in
substitution for, surface ventilators." To supplement the street
openings as much as possible with vertical cast iron or other shafts
up the house sides would seem to be the first thing to do, for there
can be no doubt that the more this is done, the more perfect will be
the ventilation of the sewers. It must also not be forgotten that the
anxiety, of late years, of English sanitarians to protect each house
from the possible dangers of sewer gas from the street sewer has led
to a system of so-called disconnection of the house drains by a water
seal or siphon trap, and that, consequently, the soil pipes of the
houses, which, when carried through the roofs, acted as ventilators to
the public sewers, have been lost for this purpose, and thus the
difficulty of sewer ventilation has been greatly increased.

In Leicester we have been fortunate enough to secure the co-operation
of factory owners, who have allowed us to connect no fewer than
fifty-two chimneys; while we have already carried out, at a cost of
about £1,250, 146 special shafts up the house sides, with a locked
opening upon a large number of them, by means of which we can test the
velocity of the current as well as the temperature of the outflowing
air. The connections with the high factory chimneys are all of too
small a caliber to be of great use, being generally only six inches,
with a few exceptionally of nine inches in diameter.

The radius of effect of specially erected chimneys, as shown by the
experiments of Sir Joseph Bazalgette, and as experienced with the
special ventilating towers erected at Frankfurt, is disappointing and
discouraging when the cost is taken into consideration. It can not be
expected, however, that manufacturers will admit larger connections to
be made with their chimney; otherwise, of course, much more
satisfactory results would be obtained. To fall back upon special
shafts up the house sides means, in my opinion, that there should be
probably as many in number as are represented by the soil pipes of the
houses, for in this we have a tested example at Frankfurt, which, so
far as I know, has up to the present moment proved eminently

The distance apart of such shafts would largely depend on the size of
them, but as a rule it will be found that house owners object to large
pipes, in which case the number must be increased, and if we take a
distance of about 30 yards, we should require about 5,000 such shafts
in Leicester. Whether some artificial means of inducing currents in
sewers by drawing down fresh air from shafts above the eaves of the
houses, and sending forth the diluted sewer gas to still higher
levels, or burning it in an outcast shaft, will take the place of
natural ventilation, and prove to be less costly and more certain in
its action, remains to be seen. But it is quite certain that
notwithstanding the patents which have already been taken out and
failed, and those now before the public, there is still a wide field
of research before this question is satisfactorily solved, so that no
cause whatever shall remain of complaint on the part of the most

One other important question common to all towns is that of the
collection and disposal of the ashes and refuse of the households. It
is one which is becoming daily more difficult to deal with, especially
in those large communities where the old privy and ashpit system has
not been entirely abolished. The removal of such ashes is at all times
a source of nuisance, and if they cannot be disposed of to the
agriculturists of the district, they become a source of difficulty. In
purely water-closeted towns the so-called dry ashpits cannot be kept
in such a condition as to be entirely free from nuisance, especially
in the summer months, inasmuch as the refuse of vegetable and animal
matter finds its way into them, and they are, in close and inhabited
districts, necessarily too close to the living apartments of the
dwellings. The tendency therefore now is rather to discourage the
establishment of ashpits by the substitution of ashbins, to be
collected daily or weekly as the case may be, and I think there can be
no doubt that from a sanitary point of view this is by far the best
system, harmonizing as it does with the general principle applicable
to town sanitation of removing all refuse, likely by decomposition to
become dangerous to health, as quickly as possible from the precincts
of human habitations.

The difficulty of disposing of the ashes, mixed as they must
necessarily be with animal and vegetable matter, is one that is
forcing itself upon the attention of all town authorities, and the
days of the rich dust contractors of the metropolis are practically
numbered. Destruction by fire seems to be the ultimate end to be aimed
at, and in this respect several towns have led the way. But as this is
a subject which will be fully dealt with by a paper to be read during
the meeting, I will not anticipate the information which will be
brought before you, further than to say that the great end to be aimed
at in this method of disposing of the ashes and refuse of towns is
greater economy in cost of construction of destructors, as well as in
cost of working them.

The progress in sanitation on the Continent, America, and the colonies
has not been coincident with the progress in England, but these
countries have largely benefited by the experience of the United
Kingdom, and in some respects their specialists take more extreme
views than those of this country in matters of detail. This is,
perhaps, more particularly the case with the Americans, who have
devised all sorts of exceptional details in connection with private
drainage, in order to protect the interior of the houses from sewer
gas, and to perfect its ventilation. In plumbing matters they seem
also to be very advanced, and to have established examinations for
plumbers and far-reaching regulations for house drainage.

Time will not permit me to examine into the works of a sanitary
character which have been undertaken in the several countries after
the example of England, but they have been attended with similar
beneficial results and saving in life and sickness as in this country,
although the Continental towns which have led the way with such works
cannot as yet point to the low rates of mortality for large towns
which have been attained in England, with the exception of the German
towns of Carlsruhe, Frankfurt, Wiesbaden, and Stuttgart, which show
death rates of 20.55, 20.64, 22, and 21.4 respectively. The greatest
reduction of the mortality by the execution of proper sewerage and
water works took place in Danzig, on the Baltic, and Linz, on the
Danube, where after the execution of the works the mortality was
reduced by 7.85 and 10.17 per 1,000 respectively, and in the case of
Danzig this reduction is almost exclusively in zymotic diseases.
Berlin is also a remarkable example of the enterprise of German
sanitarians, for there they are demonstrating to the world the
practicability of dealing with the sewage from a population of over 1¼
million upon 16,000 acres of land, of which about 10,000 acres are
already under irrigation.

In taking this chair, it has been usual, when meetings have been held
out of London, for your president to give some account of the works of
his own town. In the present instance I feel that I can dispense with
this course, in so far as that I need not do more than generally
indicate what has been the course of events since I read to a largely
attended district meeting in May, 1884, a paper on "The Public Works
of Leicester." At that time large flood prevention works were in
course of construction, under an act obtained in 1881, for continuing
the river improvement works executed under previous acts. The works
then under contract extended from the North Mill Lock and the North
Bridge on the north to the West Bridge and Bramstone Gate Bridge on
the south, along the river and canal, and included bridges, weirs,
retaining walls, and some heavy underpinning works in connection with
the widening and deepening of the river and canal. These works were
duly completed, as well as a further length of works on the River Soar
up to what is known as the old grass weir, including the Braunstone
Gate Bridge, added to one of the then running contracts, at a total
cost, excluding land and compensation, of £77,000. At this point a
halt was made in consequence of the incompleteness of the negotiations
with the land owners on the upper reach of the river, and this,
together with various other circumstances, has contributed to greater
delay in again resuming the works. In the interval, a question of
whether there should be only one channel for both river and canal
instead of two, as authorized by the act, has necessarily added
considerably to the delay. But as that has now been settled in favor
of the original parliamentary scheme, the authority of the council has
been given to proceed with the whole of the works.

One contract, now in progress, which members will have an opportunity
of inspecting, was let to Mr. Evans, of Birmingham, in March last, for
about £18,000. It consists of a stone and concrete weir, 500 feet in
length, with a lock of 7 feet 6 inches lift and large flood basins,
retaining and towing path walls, including a sunk weir parallel with
the Midland Railway viaduct. This contract is to be completed by March
next. The remainder of the works about to be entered upon include a
new canal and flood channel about 1,447 yards long, and the deepening
and widening of the River Soar for a length of about 920 yards, with
two or three bridges.

       *       *       *       *       *



Every chemist knows that cotton is chiefly composed of cellulose,
C_{6}H_{10}O_{5}, with some other substances in smaller quantities.
This, although the usual opinion, is only true in a partial sense, as
the author found on investigating samples of cotton from various
sources. Thus, while mere cellulose contains carbon 44.44 per cent.
and hydrogen 6.173, he found in Surat cotton 7.6 per cent. of
hydrogen, in American cotton 6.3 per cent., and in Egyptian cotton 7.2
per cent. The fact is that along with cellulose in ordinary cotton
there are a number of celluloid bodies derived from the inspissated
juices of the cotton plant.

In order to gain information on this subject, the author has grown
cotton under glass, and analyzed it at various stages of its life
history. In the early stage of unripeness he has found an astringent
substance in the fiber. This substance disappears as the plant ripens,
and seems to closely resemble some forms of tannin. Doubtless the
presence of this body in cotton put upon the market in an unripe
condition may account for certain dark stains sometimes appearing in
the finished calicoes. The tannin matter forms dark stains with any
compound or salt of iron, and is a great bugbear to the manufacturer.
Some years ago there was quite a panic because of the prevalence of
these stains, and people in Yorkshire began to think the spinners were
using some new or inferior kind of oil. Dr. Bowman made inquiries, and
found that in Egypt during that year the season had been very foggy
and unfavorable to the ripening of the cotton, and it seemed probable
that these tannin-like matters were present in the fiber, and led to
the disastrous results.

Although the hydrogen and oxygen present in pure cellulose are in the
same relative proportions as in water, they do not exist as water in
the compound. There is, however, in cotton a certain amount of water
present in a state of loose combination with the cellulose, and the
celluloid bodies previously referred to appear to contain water
similarly combined, but in greater proportion. Oxycellulose is another
body present in the cotton fiber. It is a triple cellulose, in which
four atoms of hydrogen are replaced by one atom of oxygen, and like
cellulose forms nitro compounds analogous to nitro glycerine. It is
probable that the presence of this oxycellulose has a marked influence
upon the behavior of cotton, especially with dye matters. The earthy
substances in cotton are also of importance. These are potassium
carbonate, chloride, and sulphate, with similar sodium salts, and
these vary in different samples of cotton, and possibly influence its
properties to some extent. Then there are oily matters in the young
fiber which, upon its ripening, become the waxy matter which Dr.
Schunk has investigated. Resin also is present, and having a high
melting point is not removed by the manipulative processes that cotton
is subjected to. When this is in excessive amount, it comes to the
surface of the goods after dyeing.

       *       *       *       *       *


MM. Vabet and Vienne, in a recent number of _Comptes Rendus_, state
that by passing a current of acetylene through 200 grammes of benzene
containing 50 grammes of aluminum chloride for 30 hours the oily
liquid remaining after removal of the unaltered aluminum chloride by
washing was found to yield, on fractional distillation, three distinct
products. The first, which came over between 143° and 145°, and which
amounted to 80 per cent. of the whole, consisted of pure cinnamene or
styrolene (C_{6}H_{5}.CH.CH_{2}), which is one of the principal
constituents of liquid storax, and was synthetized by M. Berthelot by
passing acetylene and benzene vapor through a tube heated to redness.
The second fraction, coming over at 265°-270°, consisted of diphenyl
ethane ((C_{6}H_{5})_{2} CH.CH_{3}); and the third fraction, boiling
at 280°-286°, was found to consist entirely of dibenzyl
(C_{6}H_{5}.CH_{2}.CH_{2}.C_{6}H_{5}), a solid substance isomeric with
diphenyl ethane. These syntheses afford another instance of the
singular action of aluminum chloride in attacking the benzene nucleus.

       *       *       *       *       *



Now that a supply of this reputed substitute for sugar has been placed
upon the London market, it will doubtless have attracted the attention
of many pharmacists, and as information having reference to its
characters and properties is as yet somewhat scarce, the following
notes may be of interest.

The sample to which these notes refer represents, I believe, a portion
of the first supply that has been offered to us as a commercial
article, and may therefore be taken to represent the same as it at
present occurs in commerce. I think it desirable to call attention to
this fact, because of the wide difference I have seen in other samples
obtained, I think, by special request some weeks ago, and which do not
favorably correspond with the sample under consideration, being much
more highly colored, and in comparison having a very strong odor.
Saccharin now occurs as a very pale yellow, nearly white, amorphous
powder, free from grittiness, but giving a distinct sensation of
roughness when rubbed between the fingers. It is not entirely free
from odor, but this is very slight, and not at all objectionable,
reminding one of a very slight flavor of essential oils of almonds.
Its taste is intensely sweet and persistent, which in the raw state is
followed by a slight harshness upon the tongue and palate. The
sweetness is very distinct when diluted to 1 in 10,000. Under the
microscope it presents no definite form of crystallization.

A temperature of 100° C, even if continued for some time, has no
perceptible effect upon saccharin; it loses no weight, and undergoes
no physical change. It fuses at a temperature of from 118° to 120° C.,
and at 150° C. forms a clear light yellow liquid, which boils a few
degrees higher. At the latter temperature dense white fumes appear,
and a condensation of tufts of acicular crystals (some well defined)
is found upon the cool surface of the apparatus. These crystals,
except for a slight sweetness of taste, correspond in characters and
tests to benzoic acid. The sweet flavor, I think, may be due to the
presence of a very small quantity of undecomposed saccharin, carried
mechanically with the fumes. The escaping vapors, which are very
irritable, and give a more decided odor of hydride of benzole than the
powder itself, also communicate a very distinct sensation of sweetness
to the back part of the palate. Heated over the flame, with free
access of air, saccharin carbonizes and burns with a dull yellow smoky
flame, leaving a residue amounting to 0.65 per cent. of sodium salts.
It does not reduce an alkaline copper solution, but, like glycerine,
liberates boracic acid from borax, the latter salt dissolving
saccharin readily in aqueous solution, due no doubt to a displacement
of the boracic acid.

The strong acids, either hot or cold, show no characteristic color
reaction; the compound enters solution at the boiling point of the
acid, and in the case of hydrochloric shows a white granular
separation on cooling. Sulphuric acid develops an uncharacteristic
light brown color.

The compound, like most of the organic acids, shows a characteristic
reaction with ferro and ferrid cyanide of potassium. In the former
case no change is perceptible until boiled when a greenish white
turbidity appears, with the liberation of small quantities of
hydrocyanic acid. In the latter case a trace also of this acid is set
free, with the formation of a very distinct green solution, the latter
reaction being very perceptible with a few drops of a 1 in 1,000
solution of saccharin in water. Heated with lime, very distinct odors
of benzoic aldehyde are developed.

Saccharin possesses very decided acid properties, and combines readily
with alkalies or alkaline carbonates, forming anhydro-ortho
sulphamine-benzoates of the same, in the latter case at the expense of
the carbonic anhydride, causing strong effervescence. These
combinations are very soluble in water, the alkaline carbonate thus
forming a ready medium for the solution of this acid, which alone is
so sparingly soluble. Another advantage of some importance is that,
while the harshness of flavor perceptible in a simple solution of the
acid is destroyed, the great sweetness appears to be distinctly
intensified and refined.

The following shows the solubility of saccharin in the various liquids
quoted, all, with the exception of the boiling water, being taken at
60° F.:

    Boiling water            0.60 parts per 100 by volume.
    Cold water               0.20   "        "       "
    Alcohol 0.800            4.25   "        "       "
    Rectified spirit 0.838   3.20   "        "       "
    Ether 0.717              1.00   "        "       "
    Chloroform 1.49          0.20   "        "       "
    Benzene                  0.40   "        "       "
    Petroleum ether insoluble.

It is also sparingly soluble in glycerin and fixed oils, and to a
greater or less extent in volatile oils. Benzoic aldehyde dissolves
saccharin in large quantities.

I was somewhat disappointed at the slight solubility of saccharin in
ether, as it has been repeatedly stated to be very soluble in that

The quantity of saccharin required to communicate an agreeable degree
of sweetness, like sugar, differs with the material to be sweetened;
but from half to one and half grains, according to taste, will be
found sufficient for an ordinary breakfast cup full of tea or coffee
infusion.--_Pharm. Jour._

       *       *       *       *       *


In a paper entitled "The Oxidation of Ethyl Alcohol in the Presence of
Turpentine," communicated to the Chemical Society by Mr. C.E.
Steedman, Williamstown, Victoria, the author states that dilute ethyl
alcohol in the presence of air and turpentine becomes oxidized to
acetic acid. He placed in a clear glass 16 oz. bottle a mixture of 2
drachms of alcohol, 1 drachm of turpentine, and 1 oz. of water. The
bottle was securely corked and left exposed to a varying temperature
averaging about 80° F. for three months. At the end of that time the
liquid was strongly acid from the presence of acetic acid. One curious
fact appears to have light thrown upon it by this observation.

Mr. McAlpine, Professor of Biology at Ormond College, Melbourne
University, has a method of preserving biological specimens by
abstracting their moisture with alcohol after hardening in chromic
acid, and then placing the specimen in turpentine for some time; great
discrepancies arise, however, according as the alcohol is allowed or
not to evaporate from the specimen before dipping it into turpentine.

       *       *       *       *       *



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