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Title: Scientific American Supplement, No. 484, April 11, 1885
Author: Various
Language: English
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*** Start of this LibraryBlog Digital Book "Scientific American Supplement, No. 484, April 11, 1885" ***
[Illustration]
SCIENTIFIC AMERICAN SUPPLEMENT NO. 484
NEW YORK, APRIL 11, 1885
Scientific American Supplement. Vol. XIX, No. 484.
Scientific American established 1845
Scientific American Supplement, $5 a year.
Scientific American and Supplement, $7 a year.
* * * * *
TABLE OF CONTENTS.
I. ENGINEERING AND MECHANICS.--Bridge over the Blaauw
Krantz Ravine, Cape Colony.--2 engravings.
Torpedo Ships.
The Gas Engine.--By DUGALD CLERK.--Combustion engines.--First
cylinder and piston engine.--Watt's experiments.--First gas
engine.--Principles of the gas engine.
Rapid Construction of the Canadian Pacific Railway.--By E.T.
ABBOTT.
The Osgood Mammoth Excavator.--3 figures.
Capstan Navigation on the Volga.--4 figures.
Steamboat Equipment of War Vessels.--With engraving of winch
for raising and lowering torpedo boats.
Improved Steam Trap.--1 engraving.
II. TECHNOLOGY.--Critical Methods of Detecting Errors in Plane
Surfaces.--By JOHN A. BRASHEAR.--11 figures.
Photometric Standards.--9 figures.
Bleaching or Dyeing Yarns and Goods in Vacuo.--1 figure.
On the Moulding of Porcelain.--By CHAS. LAUTH.--Moulding by
pressure of the air.--Moulding by vacuum.--Drying the moulded
pieces.--2 figures.
Photo-Tricycle Apparatus.--1 figure.
A Photo Printing Light.--1 figure.
A New Actinometer.
Astronomical Photography.
Electricity as a Preventive of Scale in Boilers.
III. DECORATIVE ART.--Alphabet designed by Godfrey Sykes.--An
engraving.
Old Wrought Iron Gate.--An engraving.
IV. GEOLOGY.--The Organization and Plan of the United States
Geological Survey.--By J.W. POWELL.--A topographic map
of the United States.--Paleontology.--Chemistry.--Physical
researches.--Statistics.--Library.--Publications.--General
geology.--Economic geology.--Relation of the general survey
to the State survey.
V. BOTANY, ETC.--The Sunflowers.--Annuals, perennials, etc.--11
engravings.
Lye's Fuchsias.--1 engraving.
VI. HYGIENE, ETC.--Brief Sanitary Matters in Connection with
Isolated Country Houses.--By E.W. BOWDITCH.
Sanitary Cooking.--By V.L. OPPENHEIMER.
Time required to digest Different Foods.
* * * * *
THE BLAAUW KRANTZ VIADUCT IN CAPE COLONY.
This viaduct is built over a rocky ravine on the railway from Port Alfred
to Grahamstown, at a height of about 200 ft. from the bottom. Its length
is 480 ft. 6 in., and the width of the platform is 15 ft., the gauge of
the railway being 3 ft. 6 in. The central span of the viaduct is an arch
of 220 ft. span between abutments, and about 90 ft. height; the remainder
of the space on each side is divided into two spans by an iron pier at a
distance of 68 ft. from the retaining wall. These piers are 36 ft. 2 in.
high, and carry girders 144 ft. long, balanced each on a pivot in the
center. One end of these girders is secured to the retaining walls by
means of horizontal and vertical anchorages, while the other end rests in
a sliding bearing on the top flange of the arch.
[Illustration: BRIDGE OVER THE BLAAUW KRANTZ RAVINE, CAPE COLONY.]
[Illustration: BRIDGE OVER THE BLAAUW KRANTZ RAVINE, CAPE COLONY.]
In designing the structure the following points had to be considered: (1)
That, on account of the great height above the ground, and on account of
the high price of timber at the site, the structure could be easily
erected without the use of scaffolding supporting it as a whole. (2) That,
on account of the high freights to Port Alfred, the quantity of iron in
the structure should be as small as possible. (3) That the single parts of
the principal span should be easy to lift, and that there should be as few
of them as possible. For this latter reason most of them were made in
lengths of 20 ft. and more. The question of economy of material presented
itself as a comparison between a few standard types, viz., the girder
bridge of small independent spans; the cantilever bridge, or the
continuous girder bridge in three large spans; the single girder bridge
with one large span and several small spans; and the arch with small
girder spans on each side. The suspension bridge was left out of question
as inadmissible. A girder bridge with small independent spans on rocker
piers would probably have been the most economical, even taking into
account the great height of the piers near the middle of the ravine, but
there would have been some difficulty in holding those piers in position
until they could be secured to the girders at the top; and, moreover, such
a structure would have been strikingly out of harmony with the character
of the site. On the other hand, a cantilever or continuous girder bridge
in three spans--although such structures have been erected in similar
localities--could not enter into comparison of simple economy of material,
because such a design would entirely disregard the anomaly that the
greater part of the structure, viz., the side spans, being necessarily
constructed to carry across a large space, would be too near the ground to
justify the omission of further supports. The question was, therefore,
narrowed to a comparison between the present arch and a central
independent girder of the same span, including the piers on which it
rests. The small side spans could obviously be left out in each case. The
comparison was made with a view not only to arrive at a decision in this
particular case, but also of answering the question of the economy of the
arch more generally. The following table contains the weights of
geometrically similar structures of three different spans, of which the
second is the one here described. The so-called theoretical weight is that
which the structure would have if no part required stiffening, leaving out
also all connections and all wind bracing. The moving load is taken at one
ton per foot lineal, and the strain on the iron at an average of four tons
per square inch. The proportion of the girder is taken at 1 in 8.
--------------+-----------------------+------------------------+
| Theoretical Weight. | Total Weight. |
Span in Feet. +-----------------------+------------------------|
| Arch. | Girder. | Arch. | Girder. |
--------------+---------+-------------+------------+-----------|
100 | 0.0724 | 0.1663 | 0.1866 | 0.2443 |
220 | 0.1659 | 0.4109 | 0.4476 | 0.7462 |
300 | 0.2414 | 0.6445 | 0.6464 | 1.2588 |
--------------+---------+-------------+------------+-----------+
|<------------Tons per foot lineal.------------->|
It can be seen from these results that the economical advantage of the
arch increases with the span. In small arches this advantage would not be
large enough to counterbalance the greater cost of manufacture; but in the
arch of 220 ft. span the advantage is already very marked. If the table
were continued, it would show that the girder, even if the platform were
artificially widened, would become impossible at a point where the arch
can still be made without difficulty. The calculations leading to the
above results would occupy too much space to make it desirable on this
occasion to produce them. Our two views are from photographs.--_The
Engineer._
* * * * *
TORPEDO SHIPS.
Commander Gallwey lately delivered an interesting lecture on the use of
torpedoes in war before the royal U.S. Institution, London, discussed
H.M.S. Polyphemus, and urged as arguments in her favor: 1. That she has
very high speed, combined with fair maneuvering powers. 2. That she can
discharge her torpedoes with certainty either ahead or on the beam when
proceeding at full speed. 3. That her crew and weapons of defense are
protected by the most perfect of all armor possible, namely, 10 ft. of
water. 4. That she only presents a mark of 4 ft. above the water line.
Then, he asked, with what weapon is the ironclad going to vanquish these
torpedo rams? Guns cannot hit her when moving at speed; she is proof
against machine guns, and, being smaller, handier, and faster than most
ironclads, should have a better chance with her ram, the more especially
as it is provided with a weapon which has been scores of times discharged
with certainty at 300 yards. The ironclad, he answered, must use
torpedoes, and then he maintained that the speed and handiness of the
Polyphemus would enable her to place herself in positions where she could
use her own torpedo to advantage, and be less likely to be hit herself. He
then called attention to the necessity for well-protected conning towers
in these ships, and prophesied that if a submarine ship, armed with
torpedoes, be ever built, she will be the most formidable antagonist an
ironclad ever had; and the nearer the special torpedo ship approaches this
desideratum the better she will be.
* * * * *
A PLUMBING TEST.
A recent trial of a smoke rocket for testing drains, described by Mr.
Cosmo Jones in the _Journal of the Society of Arts_, is deserving of
interest. The one fixed upon is 10 in. long, 2½ in. in diameter, and with
the composition "charged rather hard," so as to burn for ten minutes. This
gives the engineer time to light the fuse, insert the rocket in the drain,
insert a plug behind it, and walk through the house to see if the smoke
escapes into it at any point, finishing on the roof, where he finds the
smoke issuing in volumes from the ventilating pipes. The house
experimented upon had three ventilating pipes, and the smoke issued in
dense masses from each of them, but did not escape anywhere into the
house, showing that the pipes were sound. If the engineer wishes to
increase the severity of the test, he throws a wet cloth over the top of
the ventilating pipe, and so gets a slight pressure of smoke inside it.
* * * * *
THE GAS ENGINE.[1]
[Footnote 1: Lecture by Mr. Dugald Clerk, before the Literary and
Philosophical Society, Oldham.]
By DUGALD CLERK.
In earlier days of mechanics, before the work of the great Scottish
engineer, James Watt, the crude steam engines of the time were known as
"fire engines," not in the sense in which we now apply the term to
machines for the extinguishing of fires, but as indicating the source from
which the power was derived, motive power engines deriving their vitality
and strength from fire. The modern name--steam engine--to some extent is a
misleading one, distracting the mind from the source of power to the
medium which conveys the power. Similarly the name "Gas Engine" masks the
fact of the motors so called being really fire or heat engines.
The gas engine is more emphatically a "fire engine" than ever the steam
engine has been. In it the fire is not tamed or diluted by indirect
contact with water, but it is used direct; the fire, instead of being kept
to the boiler room, is introduced direct into the motor cylinder of the
engine. This at first sight looks very absurd and impracticable;
difficulties at once become apparent of so overwhelming a nature that the
problem seems almost an impossible one; yet this is what has been
successfully accomplished in the gas engine. Engineers accustomed to the
construction of steam engines would not many years ago have considered any
one proposing such a thing as having taken leave of his senses.
The late Sir William Siemens worked for many years on combustion engines,
some of his patents on this subject dating back to 1860. In the course of
a conversation I had with him on the subject of his earlier patents, I
asked him why he had entitled one of those patents "steam engine
improvements" when it was wholly concerned with a gas engine using
hydrogen and air in the motive cylinder, the combustion of the hydrogen
taking place in the motive cylinder. He answered me that in 1860 he did
not care to entitle his patent gas or combustion engine simply because
engineers at that time would have thought him mad.
Notwithstanding this widespread incredulity among engineers, and the
apparent novelty of the gas engine idea, fire or combustion engines have
been proposed long, long ago. The first Newcomen steam engine ever set to
work was used by a Mr. Back, of Wolverhampton, in the year 1711.
Thirty-one years before this time, in Paris--year 1680--Huyghens presented
a memoir to the Academy of Sciences describing a method of utilizing the
expansive force of gunpowder. This engineer is notable as being the very
first to propose the use of a cylinder and piston, as well as the first
combustion engine of a practical kind.
The engine consists of a vertical open topped cylinder, in which works a
piston; the piston is connected by a chain passing over a pulley above it
to a heavy weight; the upstroke is accomplished by the descent of the
weight, which pulls the piston to the top of the cylinder; gunpowder
placed in a tray at the bottom of the cylinder is now ignited, and expels
the air with which the cylinder is filled through a shifting valve, and,
after the products of combustion have cooled, a partial vacuum takes place
and the atmospheric pressure forces down the piston to the bottom of its
stroke, during which work may be obtained.
On the board I have made a sketch of this engine. Some years previous to
Huyghens' proposal, the Abbe Hautefeuille (1678) proposed a gunpowder
engine without piston for pumping water. It is similar to Savery's steam
engine, but using the pressure of the explosion instead of the pressure of
steam. This engine, however, had no piston, and was only applicable as a
pump. The Savery principle still survives in the action of the well-known
pulsometer steam pump.
Denys Papin, the pupil and assistant of Huyghens, continued experimenting
upon the production of motive power, and in 1690 published a description
of his attempts at Leipzig, entitled "A New Method of Securing Cheaply
Motive Power of Considerable Magnitude."
He mentions the gunpowder engine, and states that "until now all
experiments have been unsuccessful; and after the combustion of the
exploded powder there always remains in the cylinder one-fifth of its
volume of air."
For the explosion of the gunpowder he substituted the generation and
condensation of steam, heating the bottom of his cylinder by a fire; a
small quantity of water contained in it was vaporized, and then on
removing the fire the steam condensed and the piston was forced down. This
was substantially the Newcomen steam engine, but without the separate
boiler.
Papin died about the year 1710, a disappointed man, about the same time as
Newcomen. Thomas Newcomen, ironmonger and blacksmith, of Dartmouth,
England, had first succeeded in getting his engine to work. The hard fight
to wrest from nature a manageable motive power and to harness fire for
industrial use was continued by this clever blacksmith, and he succeeded
when the more profound but less constructively skillful philosophers had
failed.
The success of the steam method and the fight necessary to perfect it to
the utmost absorbed the energy of most able engineers--Beighton, John
Smeaton--accomplishing much in applying and perfecting it before the
appearance of James Watt upon the scene.
It is interesting to note that in England alone over 2,000 horse power of
Newcomen engines were at work before Watt commenced his series of
magnificent inventions; he commenced experimenting on a Newcomen engine
model in 1759 at Glasgow University, and in 1774 came to Birmingham,
entered into partnership with Boulton, and 1781 we find his beautiful
double acting beam condensing engine in successful work.
From that time until now the steam engine has steadily advanced,
increasing in economy of fuel from 10 lb. of coal per horse power per hour
to about 1¾ lb. per horse power per hour, which is the best result of
to-day's steam engine practice. This result, according to the highest
authorities, is so near to the theoretical result possible from a steam
engine that further improvement cannot now be looked for. Simultaneously
with the development of the steam engine, inventors continued to struggle
with the direct acting combustion or gas engine, often without any
definite understanding of why they should attempt such apparent
impossibilities, but always by their experiments and repeated failures
increasing knowledge, and forming a firm road upon which those following
them traveled to success.
In 1791 John Barber obtained a patent for an engine producing inflammable
gas, mixing it with air, igniting it, and allowing the current so produced
to impinge upon a reaction wheel, producing motion similar to the well
known Aelopile, which I have at work upon the table. About this time,
Murdoch (Jas. Watt's assistant at Birmingham) was busy introducing coal
gas into use for lighting; in 1792 Boulton and Watt's works were lighted
up with coal gas. From this time many gas engines were proposed, and the
more impracticable combustion of gunpowder received less attention.
In 1794 Thomas Mead obtained a patent for an engine using the internal
combustion of gas; the description is not a clear one, his ideas seem
confused.
In the same year Robert Street obtained a patent for an engine which is
not unlike some now in use. The bottom of a cylinder, containing a piston,
is heated by a fire, a few drops of spirits of turpentine are introduced
and evaporated by the heat, the piston is drawn up, and air entering mixes
with the inflammable vapor. A light is applied at a touch hole, and the
explosion drives up the piston, which, working on a lever, forces down the
piston of a pump for pumping water. Robt. Street adds to his description a
note: "The quantity of spirits of tar or turpentine to be made use of is
always proportional to the confined space, in general about 10 drops to a
cubic foot." This engine is quite a workable one, although the
arrangements described are very crude.
The first gas engine that was actually at work for some years; and was
applied to a variety of purposes, was Samuel Buren's. His patent was
granted in 1823, and in 1826 he built a locomotive carriage with which he
made several experimental runs in London; he also propelled a vessel with
it upon the Thames, and fitted up a large engine for pumping purposes. A
company was formed to introduce his engine, but it proved too wasteful of
fuel, and the company went into voluntary liquidation. Like almost all
engines of this time, the combustion of gas and air was used to produce a
vacuum, the piston being driven by atmospheric pressure.
Buren's locomotive carriage was thus in action three years before the
great trial in 1829, from which George Stephenson emerged victorious with
his wonderful engine "The Rocket." To those curious in the matter, I may
mention that S. Buren's patents are dated 1823, No. 4,874, and 1826, No.
5,350.
From this time on, a continuous series of gas engine patents appear, 20
engines being patented between 1826 and 1860, which is the next date
worthy of particular mention.
In this year, 1860, the famous "Lenoir" engine appeared. The use of high
pressure steam engines had long been common, and Lenoir's engine was
analogous to the high pressure engine, as Buren's was to the condensing
engine. It created a very general interest, and many engines were
constructed and used in France, England, and America; it resembled very
much in external appearance an ordinary high pressure horizontal steam
engine, and it was double acting.
During the following six years, other 20 British patents were granted, and
the gas engine passed from the state of a troublesome toy to a practicable
and widely useful machine.
From 1791 to the end of 1866, in all 46 British patents were granted for
gas engines, and in these patents are to be found the principles upon
which the gas engines of to-day are constructed, many years elapsing
before experience enough was gained to turn the proposals of the older
inventors to practical account.
The most important of these patents are:
No. Year.
Robert Street 1,983 1794 Direct-acting engine.
Samuel Buren 4,874 1823 Vacuum engine.
Samuel Buren 5,350 1826 Vacuum engine.
W.L. Wright 6,525 1833 Direct-acting engine.
Wm. Barnett 7,615 1838 Compression first proposed.
Barsante & Matteucci 1,072 1854 Rack & clutch engine.
Drake 562 1855 Direct-acting engine.
Lenoir 335 1860 D.I. engine, electric ignition.
C.W. Siemens 2,074 1860 Compression, _constant
pressure_.
Hugon 2,902 1860 Platinum ignition.
Millein 1,840 1861 Compression, both constant vol. and
_pressure_.
F.H. Wenham 1,873 1864 Free piston.
Hugon 986 1865 Flame ignition.
Otto and Langen 434 1866 Rack and clutch, flame ignition.
Leaving for the present the history of the gas engine, which brings us to
a stage comparable to the state of the steam engine during the Newcomen's
time, it will be advisable to give some consideration to the principles
concerned in the economical and efficient working of gas engines, in order
to understand the more recent developments.
It has been seen that gunpowder was the explosive used to produce a vacuum
in Huyghens' engine, and that it was abandoned in favor of gas by Buren in
1823. The reason of departure is very obvious: a gunpowder explosion and a
gaseous explosion differ in very important practical points.
Gunpowder being a solid substance is capable of being packed into a very
small space; the gas evolved by its decomposition is so great in volume
that, even in the absence of any evolution of heat, a very high pressure
would result. One cubic inch of gunpowder confined in a space of one cubic
inch would cause a pressure by the gas it contains alone of 15,000 lb. per
square inch; if the heating effect be allowed for, pressures of four times
that amount, or 60,000 lb. per square inch, are easily accounted for.
These pressures are far too high for use in any engine, and the bare
possibility of getting such pressure by accident put gunpowder quite
outside the purpose of the engineer, quite apart from any question of
comparative cost. In a proper mixture of inflammable gas and air is found
an exceedingly safe explosive, perfectly manageable and quite incapable of
producing pressures in any sense dangerous to a properly constructed
engine.
The pressure produced by the explosion of any mixture of gas and air is
strictly determined and limited, whereas the pressure produced by the
explosion of gunpowder depends greatly upon the relation between the
volume of the gunpowder and the space in which it is confined.
Engines of the "Lenoir" type are the simplest in idea and construction; in
them a mixture of gas and air is made in the cylinder during the first
half of the piston stroke, air being taken from the atmosphere and drawn
into the cylinder by the forward movement of the piston. At the same time
gas entering by a number of holes, and streaming into the air to form an
explosive mixture, the movement of a valve cuts off the supply, and brings
the igniting arrangement into action. The pressure produced by the
explosion acting upon the piston makes it complete its stroke, when the
exhaust valve opens exactly as in the steam engine. The Lenoir and Hugon
engines, the earlier forms of this type, were double acting, receiving two
impulses for every revolution of the crank, the impulse differing from
that in a high pressure steam engine in commencing at half stroke.
The Lenoir igniting arrangement was complicated and troublesome. I have it
upon the table; the mixture was ignited at the proper time by the electric
spark produced from a primary battery and Ruhmkorff coil.
The Hugon engine was an advance in this respect, using a flame ignited,
and securing greater certainty of action in a comparatively simple manner.
It is really a modification of Barnett's lighting cock described in his
patent of 1838.
Other difficulties were found in using these engines; the pistons became
exceedingly hot. In the case of the Lenoir larger engines, it sometimes
became red hot, and caused complete ruin of the cylinder by scoring and
cutting up. Hugon to prevent this injected some water.
In the all important question of economy, these engines were found
grievously wanting, Lenoir consuming 95 cubic feet per I.H.P. per hour;
Hugon consuming 85 cubic feet per I.H.P. per hour.
The surviving engines of this type are only used for very small powers,
from one to four man power, or 1/8 to 1/2 horse, the most widely known of
this kind being the "Bischoff," which is very largely used; its
consumption of gas is even greater than the Lenoir, being 110 cubic feet
per horse power per hour, as tested with a half-horse engine at a late
exhibition of gas apparatus at Stockport.
So large a consumption of gas prevented these engines coming into extended
use for engines of moderate power, and led inventors to work to obtain
better results. The force generated by the explosion of a mixture of gas
and air is very short lived, and if it is to be fully utilized must be
used quickly; a high pressure is produced, but it very quickly disappears.
The quicker the piston moves after the maximum pressure is reached, the
less will be the loss of heat to the sides of the cylinder. The flame
which fills the cylinder and causes the increase of pressure rapidly loses
heat, and the pressure falls.
The idea of using a free piston was proposed as a remedy; it was thought
that a piston connected to a crank in the ordinary manner could not move
fast enough to utilize the pressure before it was lost. Many inventors
proposed to perform work upon a piston free from any direct connection
with the crank or shaft of the engine; the explosion after attaining its
maximum pressure expends its force in giving velocity to a piston; the
velocity so acquired carries it on against atmospheric pressure until the
energy is all absorbed, and a vacuum or deficit of pressure exists in the
cylinder instead of an excess of pressure. The return stroke is
accomplished by the atmospheric pressure, and the work is now done upon
the engine shaft on the return only. The method of connecting on the
return stroke while leaving the piston free on the out stroke varies, but
in many engines the principle was the same.
Barsante and Matteucci, year 1857, British patent No. 1,625, describe the
first engine of this kind, but Messrs. Otto and Langen were the first to
successfully overcome all difficulties and make a marketable engine of it.
Their patent was dated 1866, No. 434. To distinguish it from Otto's later
patents, it may be called the rack and clutch engine.
The economy obtained by this engine was a great advance upon the Lenoir.
According to a test by Prof. Tresca, at the Paris Exhibition of 1867, the
gas consumed was 44 cubic feet per indicated horse power per hour.
According to tests I have made myself in Manchester with a two horse power
engine, Otto and Langen's free piston engine consumes 40 cubic feet per
I.H.P. per hour. This is less than one-half of the gas used by the Hugon
engine for one horse power.
The igniting arrangement is a very good modification of Barnett's lighting
cock, which I have explained already, but a slide valve is used instead of
a cock.
Other engines carried out the same principle in a different manner,
including Gilles' engine, but they were not commercially so successful as
the Otto and Langen. Mr. F.H. Wenham's engine was of this type, and was
working in England, Mr. Wenham informed me, in 1866, his patent being
taken out in 1864.
The great objection to this kind of engine is the irregularity and great
noise in working; this was so great as to prevent engines from being made
larger than three horse power. The engine, however, did good work, and was
largely used from 1866 until the end of 1876, when Mr. Otto produced his
famous engine, now known as "The Otto Silent Gas Engine." In this engine
great economy is attained without the objectionable free piston by a
method proposed first by Burnett, 1838, and also by a Frenchman, Millein,
in 1861; this method is compression before ignition. Other inventors also
described very clearly the advantages to be expected from compression, but
none were able to make it commercially successful till Mr. Otto. To him
belongs the great credit of inventing a cycle of operations capable of
realizing compression in a simple manner.
Starting from the same point as inventors did to produce the free piston
engine--namely, that the more quickly the explosive force is utilized, the
less will be the loss, and the greater the power produced from a quantity
of burning gas--it is evident that if any method can be discovered to
increase the pressure upon the piston without increasing the temperature
of the flame causing this pressure, then a great gain will result, and
the engine will convert more of the heat given to it into work. This is
exactly what is done by compression before ignition. Suppose we take a
mixture of gas and air of such proportions as to cause when exploded, or
rather ignited (because explosion is too strong a term), a pressure of 45
lb. above atmosphere, or 60 lb. per square inch absolute pressure. Then
this mixture, if compressed to half volume before igniting and kept at
constant temperature, would give, when ignited, a pressure of 120 lb.
total, or 105 lb. above atmosphere, and this without any increase of the
temperature of the flame.
The effect of compression is to make a small piston do the work of a large
one, and convert more heat into work by lessening the loss of heat through
the walls of the cylinder. In addition to this advantage, greater
expansions are made possible, and therefore greatly increase economy.
The Otto engine must be so familiar in appearance to all of you, that I
need hardly trouble you with details of its external appearance. I shall
briefly describe its action. Its strong points and its weak points are
alike caused by its cycle. One cylinder and piston suffices to carry out
its whole action. Its cycle is: First outstroke, gas and air sucked into
the cylinder; first instroke, gas and air compressed into space; second
outstroke, impulse due to ignition; second instroke, discharge of
exhausted gases. When working at full power, it gets one impulse for every
two revolutions; this seems to be a retrograde movement, but,
notwithstanding, the advantages obtained are very great. The igniting
arrangement is in the main similar to that used on the rack and clutch
engine. The engine has been exceedingly successful, and is very
economical. The Otto compression engine consumes 21 cubic feet of gas per
I.H.P. per hour, and runs with great smoothness.
In 1876 I commenced my work upon gas engines, and very soon concluded that
the compression system was the true line to proceed upon. It took me two
years to produce a workable engine. My efforts have always been directed
toward producing an engine giving at least one impulse every revolution
and, if possible, to start without hand labor, just as a steam engine
does. My first gas engine was running in 1878, and patented and exhibited
in 1879. It was first exhibited at the Kilburn Royal Agricultural
Society's show.
This engine was self-starting, gave an ignition at every revolution, and
ignited without external flame. It consisted of two cylinders, a motor,
and a compressing pump, with a small intermediate reservoir. Suitable
valves introduced the mixture of gas and air into the pump, and passed it
when compressed from the reservoir to the motor cylinder. The igniting
arrangement consisted of a platinum cage firmly fixed in a valve port;
this cage was heated in the first instance by a flame of gas and air
mixed; it became white hot in a few seconds, and then the engine was
started by opening a valve.
The platinum was kept hot by the heat derived from the successive
ignitions, and, the engine once started, no further external flame was
required. I have here one of these platinum cages which has been in use.
Finding this method not well suited for small engines, I produced the
engine which is at present in the market under my name.
The cycle is different, and is designed for greater simplicity and the
avoidance of back ignitions. It also consists of two cylinders, motor
cylinder and the displace or charging cylinder. There is no intermediate
reservoir. The displace crank leads the motor by a right angle, and takes
into it the mixed charge of gas and air, in some cases taking air alone
during the latter part of its stroke.
The motor on the outstroke crosses V-shaped parts about from one-sixth to
one-seventh from the out end, the displacer charge now passing into the
motor cylinder, displacing the exhaust gases by these ports and filling
the cylinder and the space at the end of it with the explosive mixture.
The introduction of some air in advance of the charge serves the double
purpose of cooling down the exhaust gases and preventing direct contact of
the inflammable mixture with flame which may linger in the cylinder from
the previous stroke. The instroke of the motor compresses the charge into
the conical space at the end of the cylinder, and, when fully compressed,
ignition is effected by means of the slide I have upon the table.
This system of ignition has been found very reliable, and capable of
acting as often as 400 times per minute, which the Otto ignite is quite
incapable of doing. By this cycle the advantages of compression are gained
and one step nearer to the steam engine is attained, that is, an impulse
is given for every revolution of the engine.
As a consequence, I am able with my engine to give a greater amount of
power for a comparatively small weight. In addition to this, I have
introduced a method of self-starting; in this I believe I was the
first--about 100 of my engines are now using self-starting.
The largest single engine I have yet made indicates 30 H.P. The
consumption of gas in Glasgow is: Clerk engine consumes in Glasgow 18
cubic feet per I.H.P. per hour; Clerk engine consumes in Manchester 22
cubic feet per I.H.P. per hour. So far as I know, the Otto engine and my
own are the only compression engines which have as yet made any success in
the market. Other engines are being continually prepared, gas engine
patents being taken out just now at the rate of 60 per annum, but none of
them have been able as yet to get beyond the experimental stage. The
reason is simply the great experience necessary to produce these machines,
which seem so very simple; but to the inexperienced inventor the subject
fairly bristles with pitfalls.
I have here sections of some of the earlier engines, including Dr.
Siemens' and Messrs. Simon and Beechy. Although interesting and containing
many good points, these have not been practically successful.
The Simon engine is an adaptation of the well-known American petroleum
motor, the Brayton, the only difference consisting in the use of steam as
well as flame.
Dr. Siemens worked for some twenty years on gas engines, but he aimed
rather high at first to attain even moderate success. Had he lived, I
doubt not but that he would have succeeded in introducing them for large
powers. In 1882 he informed me that he had in hand a set of gas engines of
some hundreds of horse power for use on board ship, to be supplied with
gas from one of his gas producers modified to suit the altered
conditions.
Summarizing the ground over which we have passed, we find the origin of
the gas engine in the minds of the same men as were first to propose the
steam engine, Huyghens and Papin, 1680 and 1690. Greater mechanical
difficulties and ignorance of the nature of explosives caused the
abandonment of the internal combustion idea, and the mechanical
difficulties with steam being less, the steam engine became successful,
and triumphed over its rival. The knowledge and skill gained in the
construction of steam engines made it possible once again to attack the
more difficult problem, and simultaneously with the introduction and
perfecting of the steam engine, the gas engine idea became more and more
possible, the practicable stage commencing with Lenoir and continuing with
Hugon, Millein, Otto and Langen, F.H. Wenham, then Otto and Clerk. In
1860, 95 cubic feet of gas produced one horse power for an hour; in 1867,
40 cubic feet accomplished the same thing; and now (1885) we can get one
horse power for an hour for from 15 to 20 cubic feet of gas, depending on
the size of the engine used.
Considered as a heat engine, the gas engine is now twice as efficient as
the very best modern steam engine. It is true the fuel used at present
is more expensive than coal, and for large powers the steam engine is
the best because of this. But the way is clearing to change this. Gas
engines as at present, if supplied with producer gas, produced direct
from coal without leaving any coke, as is done in the Siemens, the
Wilson, and the Dawson producers, will give power at one-half the cost
of steam power. They will use 7/8 of a pound of coal per horse power per
hour, instead of 1-3/4 lb., as is done in the best steam engines. The
only producer that makes gas for gas engines at present is the Dawson,
and in it anthracite is used, because of the difficulty of getting rid
of the tar coming from the Siemens and Wilson producers, using any
ordinary slack.
When this difficulty has been overcome, and that it will be overcome there
can be no manner of doubt, gas engines will rapidly displace the steam
engine, because a gas engine with a gas producer, producing gas from any
ordinary coal with the same ease as steam is produced from a boiler, will
be much safer, and will use one-half the fuel of the very best steam
engines for equal power. The first cost also will not be greater than that
of steam. The engine itself will be more expensive than a steam engine of
equal power, but the gas producer will be less expensive than the boiler
at present. Perfect as the gas engine now is, considered as a machine for
converting heat into work, the possibility of great development is not yet
exhausted. Its economy may be increased two or even three fold; in this
lies the brilliant future before it. The steam engine is nearly as perfect
as it can be made; it approaches very nearly the possibility of its
theory. Its defect does not lie in its mechanism, but in the very
properties of water and steam itself. The loss of heat which takes place
in converting liquid water into gaseous steam is so great that by far the
greater portion of the heat given out by the fuel passes away either in
the condenser or the exhaust of a steam engine; but a small proportion of
the heat is converted into work.
The very best steam engines convert about 11 per cent. of the heat given
them into useful work, the remaining 89 per cent. being wasted,
principally in the exhaust of the engine.
Gas engines now convert 20 per cent. of the heat given to them into work,
and very probably will, in a few years more, convert 60 per cent. into
useful work. The conclusion, then, is irresistible that, when engineers
have gained greater experience with gas engines and gas producers, they
will displace steam engines entirely for every use--mills, locomotives,
and ships.
* * * * *
RAPID CONSTRUCTION OF THE CANADIAN PACIFIC RAILWAY.
By E.T. ABBOTT, Member of the Engineers' Club of Minnesota. Read December
12, 1884.
During the winter of 1881 and 1882, the contract was let to Messrs.
Langdon, Sheppard & Co., of Minneapolis, to construct during the working
season of the latter year, or prior to January 1, 1883, 500 miles of
railroad on the western extension of the above company; the contract being
for the grading, bridging, track-laying, and surfacing, also including the
laying of the necessary depot sidings and their grading. The idea that any
such amount of road could be built in that country in that time was looked
upon by the writer hereof, as well as by railroad men generally, as a huge
joke, perpetrated to gull the Canadians. At the time the contract was let,
the Canadian Pacific Railway was in operation to Brandon, the crossing of
the Assiniboine River, 132 miles west of Winnipeg. The track was laid,
however, to a point about 50 miles west of this, and the grading done
generally in an unfinished state for thirty miles further. This was the
condition of things when the contract was entered into to build 500
miles--the east end of the 500-mile contract being at Station 4,660
(Station being at Brandon) and extending west to a few miles beyond the
Saskatchewan River.
The spring of 1882 opened in the most unpromising manner for railroad
operations, being the wettest ever known in that country. Traffic over the
St. Paul, Minneapolis & Manitoba Railroad, between St. Paul and Winnipeg,
was entirely suspended from April 15 to the 28th, owing to the floods on
the Red River at St. Vincent and Emerson, a serious blow to an early
start, as on this single track depended the transportation of all
supplies, men, timber, and contractors' plant, together with all track
materials (except ties), all of these things having to come from or
through St. Paul and Minneapolis. The writer hereof was appointed a
division engineer, and reported at Winnipeg the 15th of April, getting
through on the last train before the St. Vincent flood. No sooner was the
line open from St. Paul to Winnipeg than the cotillon opened between
Winnipeg and Brandon, with a succession of washouts that defied and
defeated all efforts to get trains over, so it was not until the fifth day
of May that I left Winnipeg to take charge of the second division of 30
miles.
By extremely "dizzy" speed I was landed at the end of the track, 180 miles
from Winnipeg, on the evening of the 9th (4 days). My outfit consisted of
three assistant engineers and the necessary paraphernalia for three
complete camps, 30 days' provisions (which turned out to be about 20), 11
carts and ponies, the latter being extremely poor after a winter's diet
on buffalo grass and no grain. On the 18th day of May I had my division
organized and camps in running order. The country was literally under
water, dry ground being the exception, and I look upon the feat of getting
across the country at all as the engineering triumph of my life.
On May 20 a genuine blizzard set in, lasting 24 hours, snowed five inches,
and froze the sloughs over with half an inch of ice, a decidedly
interesting event to the writer, as he was 18 miles from the nearest wood,
therefore lay in his blankets and ate hard tack. I stabled my ponies in
the cook tent, and after they had literally eaten of the sod inside the
tent, I divided my floor with them.
On 28th day of May I saw the first contractor, who broke ground at station
7,150. On the 1st of June I was relieved from this division, and ordered
to take the next, 50 miles west. On the 13th day of June ground was broken
on this division, at station 8,070, or only about 62 miles west of the
east end of the 500-mile contract. It looked at this time as though they
might build 150 miles, but not more. But from this time on very rapid
progress was made. On July 17 the track reached station 7,000, making
however up to this time but about 50 miles of track-laying, including that
laid on the old grade; but large forces were put on to surfacing, and the
track already laid was put in excellent condition for getting material to
the front. The weather from this until the freezing-up was all that could
be desired. Work ceased about the 1st of January, 1883, for the season,
and the final estimate for the work was as follows: 6,103,986 cubic yards
earth excavation, 2,395,750 feet B.M. timber in bridges and the culverts,
85,708 lineal feet piling, 435 miles of track-laying. This work was all
done in 182 working days, including stormy ones, when little, if anything,
could be done, making a daily average of 33,548 yards excavation, 13,150
feet B.M. timber, 471 feet piling, 2-38/100 miles track-laying. We never
had an accurate force report made of the whole line, but roughly there
were employed 5,000 men and 1,700 teams.
The admirable organization of the contractors was something wonderful. The
grading work was practically all done by sub-contractors, Messrs. Langdon,
Sheppard & Co. confining themselves to putting in the supplies and doing
the bridge work, surfacing, and track-laying. The grading forces were
scattered along about 150 miles ahead of the track and supply stores,
established about 50 miles apart, and in no case were sub-contractors
expected to haul supplies over 100 miles. If I remember rightly, there
were four trains of about forty wagons each, hauling supplies from the end
of track to the stores.
As can be readily seen, the vital point of the whole work, and the problem
to solve, was food for men and horses. 1,700 bushels of oats every day and
15,000 pounds of provisions, Sundays and all, for an entire season, which
at the beginning of the work had to come about 170 miles by rail, and then
be taken from 50 to 150 miles by teams across a wilderness, is on the face
of it considerable of an undertaking, to say nothing about hauling the
pile-drivers, piles, and bridge-timber there. To keep from delaying the
track, sidings 1,500 feet long were graded, about 7 miles apart. A
side-track crew, together with an engine, four flats, and caboose, were
always in readiness; and as soon as a siding was reached, in five hours
the switches would be in, and the next day it would be surfaced and all in
working order, when the operating department would fill it with track
material and supplies. From the head of the siding to the end of the track
the ground was in hands of track-laying engine, never going back of the
last siding for supplies or material, and my recollection is that there
were but six hours' delay to the track from lack of material the whole
season, at any rate up to some time in November. The track-laying crew was
equal to 4 miles per day, and in the month of August 92 miles of track
were laid. The ties were cut on the line of the road about 100 miles east
of Winnipeg, so the shortest distance any ties were hauled was 270 miles;
the actual daily burden of the single track from Winnipeg west was 24 cars
steel, 24 cars ties, aside from the transportation of grain and
provisions, bridge material, and lumber for station houses. The station
buildings were kept right up by the company itself, and a depot built with
rooms for the agent every 15 miles, or at every second siding. The
importance of keeping the buildings up with the track was impressed on the
mind of the superintendent of this branch, and, as a satire, he
telegraphed asking permission to haul his stuff ahead of the track by
teams, he being on the track-layers' heels with his stations and tanks the
whole season. The telegraph line was also built, and kept right up to the
end of the track, three or four miles being the furthest they were at any
time behind.
It might be supposed that work done so rapidly would not be well done, but
it is the best built prairie road I know of on this continent. It is built
almost entirely free from cuts, and the work is at least 20 per cent.
heavier than would ordinarily be made across the same country in the
States, on account of snow. 2,640 ties were laid to the mile, and the
track ballasting kept well up with the laying; so well, in fact, and so
well done, that as 100 mile sections were completed schedule trains were
put on 20 miles an hour, and the operating department had nothing to do
but make a time table; the road was _built_ by the construction department
before the operating department was asked to take it. The engineering was
organized in divisions of 30 miles each, and as each was finished the
parties moved ahead again to the front, the engineers usually finding men
sitting on their shovels waiting for the work to be laid out for them. It
was as much as the locating parties could do to keep out of the way of the
construction. The roadbed was built 14 ft. wide in embankment and 20 in
the very few cuts there were, there being no cuts of any moment except
through the Coteaus and the Saskatchewan crossing, and these have since
been widened out on account of snow, so that the road can be operated the
year round and the bucking-snow account cut no figure in the operating
expenses.
The country is a virgin desert. From Winnipeg to the Pacific Ocean there
are a few places that might attain to the dignity of an _oasis_--at
Brandon, Portage la Prairie, etc.--but it is generally what I should call
worthless; 100 miles to wood and 100 feet to water was the general
experience west of the Moose jaw, and the months of June, July, and August
are the only three in the year that it is safe to bet you will not have
sleighing. I burned wood and used stakes that were hauled by carts 85
miles, and none any nearer. It is a matter of some pride that both the
engineering and the construction were done by what our Canadian neighbors
kindly termed "Yankee importations." However, there was one thing that in
the building of this road was in marked contrast to any other Pacific road
ever constructed, that is, there was no lawlessness, no whisky, and not
even a knock-down fight that I ever heard of the whole season, and even in
the midst of 12,000 Indians, all armed with Winchester rifles and plenty
of ammunition, not one of the locating or construction parties ever had a
military escort, nor were any depredations ever committed, except the
running off of a few horses, which were usually recovered; and I think
there were but two fatal accidents during the season, one man killed on
the Grand Coule Bridge, and another from being kicked by a horse.
The track was all laid from one end, and in no case were rails hauled
ahead by teams. Two iron cars were used, the empty returning one being
turned up beside the track to let the loaded one by.
The feat in rapid construction accomplished by this company will never be
duplicated, done as it was by a reckless expenditure of money, the orders
to the engineers being to _get there_ regardless of expense and
horse-flesh; if you killed a horse by hard driving, his harness would fit
another, and there was no scrutiny bestowed on vouchers when the work was
done; and I must pay the tribute to the company to say that everything
that money would buy was sent to make the engineers comfortable. It was
bad enough at best, and the Chief Engineer (J.C. James) rightly considered
that any expense bestowed on the engineering part of the work was a good
investment.
* * * * *
THE OSGOOD MAMMOTH EXCAVATOR.
In the accompanying illustration, we present to our readers a mammoth
excavator, built by the Osgood Dredge Company of Albany, N.Y., for the
Pacific Guano Company of California, for uncovering their phosphate
deposits on Chisholm Island, South Colombia.
[Illustration: THE OSGOOD MAMMOTH EXCAVATOR.]
In order to bring out more clearly the principal problem involved in the
construction of this machine, we shall state first the proposed method of
its operation. This is as follows, viz.: The excavator is to dig a trench
thirty feet wide, down to the phosphate rock, and the entire length of the
bed--about one quarter of a mile--dumping the earth of the first cut to
one side. The phosphate is taken out behind the excavator. On reaching the
end of the bed, the excavator is reversed and starts back, making a second
cut thirty feet wide, and dumping now into the cut from which the
phosphate has just been removed. In this way the entire bed is traversed,
the excavator turning over the earth in great furrows thirty feet wide,
and giving an opportunity to simultaneously get out all the phosphate.
As will be seen, the main problem presented was to turn the car around at
each end of the cut in a very limited space. To accomplish this, the car
is mounted on a fixed axle at each end and on a truck under its center of
gravity; this is somewhat forward of the geometrical center of the car.
The frame of the truck is circular, thirteen feet in diameter, made of I
beams curved to shape. The circle carries a track, on which a ring of
coned rollers revolves, which in turn supports the car. By pulling out the
track from under both ends of the car, the whole weight is balanced on
this central turntable truck, thus admitting of the car being turned, end
for end, within its own length. This method of turning the car, and the
size of the machine, are the principal features.
The car is 40' × 13', with arched truss sides. The track is seven feet
gauge, the spread between tracks 20 feet, the height of the A frame 38
feet, length of boom 40 feet, swinging in a circle of 30 feet radius, and
through two-thirds of the entire circle. It has a steel dipper of 46 cubic
feet capacity, 1 inch steel chains, 10" × 12" double cylinder hoisting
engine, and 6¼" × 8" double cylinder reversible crowding engine. The
drums are fitted with friction clutches. Owing to the great distance at
which the dipper is handled, its size is reduced, and because it swings on
the arc of so large a circle the capacity of this machine is only one-half
of that of the No. 1 excavator built by the Osgood Dredge Company.
Nevertheless it will do the work of from 75 to 100 men, since its capacity
is from 800 to 1,000 cubic yards per day, the amount of rock _uncovered_
depending, of course, upon the depth of earth overlying it. The excavator
will dump 30 feet from the center line of the car, and 26 feet above the
track, which is laid on the rock. Total weight about fifty tons. The crew
required for its operation consists of 1 engineer, 1 fireman, 1 craneman,
and 4 to 5 pit men to tend jacks, move track, etc.
In the illustration the boiler connections are omitted, also the housing
for the protection of the crew. The design is characterized by the evident
care which has been bestowed upon securing simplicity and
durability.--_American Engineer._
* * * * *
THE OSGOOD EXCAVATOR.
At a recent meeting of the Engineers' Club of Philadelphia, Mr. John C.
Trautwine, Jr., exhibited and described drawings of a large land dredge
built by the Osgood Dredge Co., of Albany, New York, for the Pacific Guano
Co., to be used in removing 8 to 15 feet of material from the phosphate
rock at Bull River, S.C.
The more prominent features of the machine are the car-body, the water
tank, boiler and engine, the A frame (so-called from its slight
resemblance to the letter A), the boom, the dipper-handle; and the dipper,
drawings of which were shown and described in detail.
Before the excavation is begun, the forward end of the car (the end
nearest the dipper) is lifted clear of the track by means of 3
screw-jacks. When the machine has excavated as far in advance of itself as
the length of the boom and that of the dipper-handle will permit, say
about 8 feet, the car is again lowered to the track, the screw-jacks
removed, and the car is moved forward about 8 feet by winding the rope
upon the drum, the other end of the rope being attached to any suitable
fixed object near the line of the track. The forward end of the car is
then again lifted by means of the 3 screw-jacks, and the digging is
resumed. The machine cuts a channel from 25 to 35 feet wide, and deposits
all the dirt upon one side. If necessary, it can dump earth about 25 feet
above the track. The miners follow in the wake of the machine, getting out
the phosphate as fast as it is uncovered. When the machine reaches the end
of the field it is lowered to the track and the screw-jacks are removed.
Shoes or skids are then placed upon the track, and the wheels of the
turntable are run up on them. This lifts the end wheels clear of the
track, so that the car and machine rest entirely upon the turntable. By
now blocking the turntable wheels and winding up only _one_ of the ropes,
the car body and the machine are swung around end for end. The digging is
then resumed in the opposite direction, the temporary track, upon which
the machine travels, being shifted to one side, so that the second channel
is made alongside of the first. The earth removed in cutting this second
channel is dumped into the first channel, the phosphate (as stated above)
having been first removed.
The dipper is of plate steel, and holds 1¾ cubic yards of earth when even
full.
The machine is manned by an engineer, a fireman, and a dipper-tender,
besides which from five to ten laborers are required. These look after the
track, etc.
* * * * *
CAPSTAN NAVIGATION ON THE VOLGA.
On several of the large rivers on the Continent, with rapid currents,
cable towage has been introduced in addition to the older methods of
transporting merchandise by sailing and steam boats or by towage with
screw or paddle tugs. A chain or wire rope is laid on the bottom of the
river bed, fixed to anchors at the ends and passed over a chain pulley
driven by the steam engine and guided by pulleys on the steam tug, the tug
lifting it out of the water at the bow and dropping it over the stern and
winding itself with the barges attached to it along the chain, the latter
being utilized as a rule only for the up journey, while down the river the
tugs are propelled by paddles or screws, and can tow a sufficient number
of barges with the assistance of the current. The system has been found
advantageous, as, although the power required for drawing the barges and
tugs against the current is of course the same in all cases, the slip and
waste of power by screws and paddles is avoided. The size of the screws or
paddles is also limited by the nature of the river and its traffic, and
with cable towage a larger number of barges can be hauled, while the
progress made is definite and there is no drifting back, as occurs with
paddle or screw tugs when they have temporarily to slow or stop their
engines on account of passing vessels. Several streams, as the Elbe,
Rhine, and Rhone, have now such cables laid for long distances in those
parts of the rivers where the traffic is sufficient to warrant the
adoption of the system. While this has been introduced only during the
last 16 or 18 years, a similar method of transporting merchandise has been
in use in Russia on the river Volga for upward of 40 years. Navigation on
this river is interrupted for about half the year by the ice, and the
traffic is of larger amount only during part of the summer, while the
length of the river itself is very great, so that laying down permanent
cables would not pay; while, on the other hand, the current is so strong
that towage of some sort must be resorted to for the transport of large
quantities. The problem has been solved by the introduction of the capstan
navigation or towage.
[Illustration: CAPSTAN NAVIGATION ON THE VOLGA.]
There are two kinds of capstans in use, one actuated by horse-power and
the other by steam engines. A horse capstan boat carries according to size
150 to 200 horses, which are stabled in the hold. On deck a number of
horse gears are arranged at which the horses work. The power of the
separate gears is transmitted to a main shaft, which is connected to the
drums that wind on the rope. The horses work under an awning to protect
them from the burning sunshine, and are changed every three hours. Eight
and sometimes ten horses work at each horse gear. The horses are changed
without interruption of the work, the gears being disengaged from the main
shaft in rotation and the horses taken out and put in while the gear is
standing. The horses are bought at the place of departure in the south of
Russia and resold at the destination, usually Nishny-Novgorod, at a fair
profit, the capstan boat carrying fodder and provender for the attendants.
The capstan is accompanied by a steam launch which carries the anchor and
hawser forward in advance of the capstan. The latter has a diameter of as
much as 5 in., and is two to three miles in length. The anchor is dropped
by the tug and the hawser carried back to the capstan, where it is
attached to one of the rope drums, and the boat with the barges attached
to it towed along by the horse gears described above winding on the
hawser. The advance continues without interruption day and night, the
launch taking a second anchor and hawser forward and dropping the anchor
in advance of the first by a hawser's length, so that when the capstan has
wound up the first hawser it finds a second one ready for attachment to
the rope drum. The launch receives the first hawser, picks up the anchor,
and passes the capstan to drop it again in advance of the anchor
previously placed, and carries the hawser back to the capstan, and so on.
A capstan tows twelve or more barges, placed in twos or threes beside and
close behind each other, with a load of a million pounds, or about 16,000
to 17,000 tons. From Astrachan and the mouth of the Kama the capstans make
during the season from the beginning of May to the end of July in the most
favorable case two journeys to the fair of Nishny-Novgorod; after this
time no more journeys are made, as the freights are wanting. At the end of
the up-stream journey the horses are sold, as mentioned before, and the
capstan towed down stream by the steam launch to Astrachan or the Kama
mouth, where meanwhile a fresh lot of barges has been loaded and got
ready, a new supply of horses is bought, and the operation repeated.
Besides these horse capstans there are steam capstans which are less
complicated and have condensing steam engines of about 100 horse power,
the power being transmitted by gearing to the rope drum. The rope drum
shaft projects on both sides beyond the boards of the boat, and for the
return journey paddle wheels, are put on to assist the launch in towing
the clumsy and big capstan boat down the river. The steam capstans tow
considerably larger masses of goods than the horse capstans and also
travel somewhat quicker, so that the launch has scarcely sufficient time
to drop and raise the anchors and also to make double the journey. We do
not doubt that this system of towage might with suitable modifications be
advantageously employed on the large rivers in America and elsewhere for
the slow transport of large quantities of raw materials and other bulky
merchandise, a low speed being, as is well known, much more economical
than a high speed, as many of the resistances increase as the square and
even higher powers of the velocity.
* * * * *
STEAMBOAT EQUIPMENT OF WAR VESSELS.
The larger ships in the navy, and some of the more recent small ones, such
as the new cruisers of the Phaeton class, are fitted with powerful steam
winches of a type made by Messrs. Belliss and Co. These are used for
lifting the pinnaces and torpedo boats.
We give an illustration of one of these winches. The cylinders are 6 in.
in diameter and 10 in. stroke. The barrel is grooved for wire rope, and is
safe to raise the second class steel torpedo boats, weighing nearly 12
tons as lifted. The worm gearing is very carefully cut, so that the work
can be done quietly and safely. With machinery of this kind a boat is soon
put into the water, and as an arrangement is fitted for filling the boat's
boilers with hot water from the ship's boilers, the small craft can be
under way in a very short time from the order being given.
Mr. White is fitting compound engines with outside condensers to boats as
small as 21 ft. long, and we give a view of a pair of compound engines of
a new design, which Messrs. Belliss are making for the boats of this
class. The cylinders are 4 in. and 7 in. in diameter by 5 in. stroke. The
general arrangement is well shown in the engraving. On a trial recently
made, a 25 ft. cutter with this type of engines reached a speed of 7.4
knots.
About three years ago the late Controller of the Navy, Admiral Sir W.
Houston Stewart, wished to ascertain the relative consumption of fuel in
various classes of small vessels. An order was accordingly sent to
Portsmouth, and a series of trials were made. From the official reports of
these we extract the information contained in tables F and G, and we think
the details cannot fail to be of interest to our readers. The run around
the island was made in company with other boats, without stopping, and
observations were taken every half hour. The power given out by the
engines was fairly constant throughout. The distance covered was 56 knots,
and the total amount of fuel consumed, including that required for raising
steam, was 1,218 lb. of coal and 84 lb. of wood. The time taken in raising
steam to 60 lb. pressure was forty-three minutes. The rate of consumption
of fuel is of course not the lowest that could be obtained, as a speed of
over 10 knots is higher than that at which the machinery could be worked
most economically.
[Illustration: STEAM WINCH FOR HOISTING AND LOWERING PINNACLES AND
TORPEDO BOATS.]
The trials afterward made to find the best results that could be obtained
in fuel consumption were rather spoiled by the roughness of the weather on
the day they were made. The same boat was run for 10 miles around the
measured mile buoys in Stokes Bay. The following are some of the results
recorded:
_Table F.--Report of Trials of Engines of H.M. 48 ft.
Twin Screw Steam Pinnace, No. 110._
Date August 4, 1881.
Where tried Round the Isle of
Wight
Draught of water / Forward 3 ft. ½ in.
\ Aft 3 ft. 6½ in.
Average boiler pressure 104.81 lb.
Average pressure in receivers / Starboard 16.27 "
\ Port 16.54 "
Mean air pressure in stokehold 1.4 in. water.
Vacuum in condenser, average 26.72 in.
Weather barometer 30.37 "
Revolutions per minute / Starboard 240.75
\ Port 251.95
lb.
Mean pressure in cylinders / Starboard / High 45.33
| \ Low 16.16
\ Port / High 43.16
\ Low 15.3
Indicated horse-power / Starboard / High 18.20
| \ Low 16.32
| Port / High 18.13
| \ Low 16.17
\ Collective Total 68.82
Speed by log 10.18 knots.
Force of wind One.
Sea Smooth.
Quantity of coal on board 1 ton.
Description Nixon's navigation.
Consumption per indicated horse-power per hour 4.17 lb.
Time under way 5 hrs. 30 min.
_Table G.--Report of Trial of Engines of H.M. 48 ft. Steam Pinnace No.
110._
When tried August 3, 1881.
Where tried Stokes Bay.
Draught / Forward 3 ft. 1 in.
\ Aft 3 ft. 3¼ in.
Average boiler pressure 55.52 lb.
Vacuum 25.12 in.
Weather barometer 30.35 "
Revolutions per minute / starboard 165.54
\ port 161.55
Indicated horse-power[2] / Starboard / High 5.05
| \ Low 5.53
| Port / High 3.75
| \ Low 4.02
\ Collective Total 18.35
Speed of vessel by log (approximate) 7.404
Wind / Force 4 to 5
\ Direction Bow and Quarter.
State of sea Rough.
[Footnote 2: In consequence of the seas breaking over the boat, a large
number of diagrams were destroyed, and, on account of the roughness of the
weather, cards were only taken with the greatest difficulty. The records
of power developed are therefore not put forward as authoritative.]
In connection with this subject it may perhaps be of interest to give
particulars of a French and American steam launch; these we extract from
the United States official report before mentioned.
_Steam Launch of the French Steamer Mouche_.
Length on low water level 27 ft. 10-1/2 in.
Breadth 5 ft. 11 in.
Depth to rabbet of keel 3 ft. 3-1/3 in.
Draught of water aft 2 ft. 1-1/2 in.
Weight of hull and fittings 2,646 lb.
Weight of machinery with water in boiler 3,473 lb.
The boat is built of wood, and coppered. The engine consists of one
non-condensing cylinder, 7-1/2 in. in diameter and 5.9 in. stroke. The
boiler has 4.3 square feet of grate surface. The screw is 21-2/3 in. in
diameter by 43.3 in, pitch. The speed is 7 knots per hour obtained with
245 revolutions per minute, the slip being 19.7 per cent. of the speed.
The United States navy steam cutters built at the Philadelphia navy yard
are of the following dimensions:
Length 27 ft. 7½ in.
Breadth 7 ft. 10 in.
Depth to rabbet of keel 3 ft. 11¾ in.
Displacement (to two feet above rabbet of keel) 5.96 tons.
Weight of hull and fittings 4,675 lb.
" engine 1,240 "
" boiler 3,112 "
" water in boiler and tanks 2,696 "
The engine has a single cylinder 8 in. in diameter and 8 in. stroke of
piston. The screw is four bladed, 4 in. long and 31 in. in diameter by 45
in. pitch. The following is the performance at draught of water 2 feet
above rabbet of keel:
Boiler pressure 90 lb.
Revolutions 353
Speed 7.8 knots.
Indicated horse power. 53
These boats are of 1870 type, but may be taken as typical of a large
number of steam cutters in the United States navy. The naval authorities
have, however, been lately engaged in extensive experiments with compound
condensing engines in small boats, and the results have proved so
conclusively the advantages of the latter system that it will doubtless be
largely adopted in future.--_Engineer._
* * * * *
IMPROVED STEAM TRAP.
The illustrations we give represent an expansion trap by Mr. Hyde, and
made by Mr. S. Farron, Ashton-under-Lyne. The general appearance of this
arrangement is as in Fig. 1 or Fig. 3, the center view, Fig. 2, showing
what is the cardinal feature of the trap, viz., that it contains a
collector for silt, sand, or sediment which is not, as in most other
traps, carried out through the valve with the efflux of water. The escape
valve also is made very large, so that while the trap may be made short,
or, in other words, the expansion pipe may not be long, a tolerably large
area of outlet is obtained with the short lift due to the small movement
of the expansion pipe.
[Illustration: IMPROVED STEAM TRAP.]
The object of a steam trap is for the removal of water of condensation
without allowing the escape of steam from drying apparatus and steam pipes
used for heating, power, or other purposes. One of the plans employed is
by an expansion pipe having a valve fixed to its end, so that when the
pipe shortens from being cooler, due to the presence of the water, the
valve opens and allows the escape of the water until the steam comes to
the trap, which, being hotter, lengthens the pipe and closes the valve.
Now with this kind of trap, and, in fact, with any variety of trap, we
understand that it has been frequently the experience of the user to find
his contrivance inoperative because the silt or sand that may be present
in the pipes has been carried to the valve and lodged there by the water,
causing it to stick, and with expansion traps not to close properly or to
work abnormally some way or other. The putting of these contrivances to
rights involves a certain amount of trouble, which is completely obviated
by the arrangement shown in the annexed engravings, which is certainly a
simple, strong, and substantial article. The foot of the trap is made of
cast iron, the seat of the valve being of gun metal, let into the
diaphragm, cast inside the hollow cylinder. The valve, D, is also of gun
metal, and passing to outside through a stuffing box is connected to the
central expansion pipe by a nut at E. The valve is set by two brass nuts
at the top, so as to be just tight when steam hot; if, then, from the
presence of water the trap is cooled, the pipe contracts and the water
escapes. A mud door is provided, by which the mud can be removed as
required. The silt or dirt that may be in the pipes is carried to the trap
by the water, and is deposited in the cavity, as shown, the water rises,
and when the valve, D, opens escapes at the pipe, F, and may be allowed to
run to waste. A pipe is not shown attached to F, but needless to say one
may be connected and led anywhere, provided the steam pressure is
sufficient. For this purpose the stuffing-box is provided; it is really
not required if the water runs to waste, as is represented in the
engraving. To give our readers some idea of the dimensions of the valve,
we may say that the smallest size of trap has 1 in. expansion pipe and a
valve 3 in. diameter, the next size 1¼ in. expansion pipe and a valve 4½
in. diameter, and the largest size has a pipe 1½ in. and a valve 6 in.
diameter. Altogether, the contrivance has some important practical
advantages to recommend it.--_Mech. World._
* * * * *
CRITICAL METHODS OF DETECTING ERRORS IN PLANE SURFACES.[3]
[Footnote 3: A paper read before the Engineers' Society of Western
Pennsylvania, Dec. 10, 1884.]
By JOHN A. BRASHEAR.
In our study of the exact methods of measurement in use to-day, in the
various branches of scientific investigation, we should not forget that it
has been a plant of very slow growth, and it is interesting indeed to
glance along the pathway of the past to see how step by step our micron of
to-day has been evolved from the cubit, the hand's breadth, the span, and,
if you please, the barleycorn of our schoolboy days. It would also be a
pleasant task to investigate the properties of the gnomon of the Chinese,
Egyptians, and Peruvians, the scarphie of Eratosthenes, the astrolabe of
Hipparchus, the parallactic rules of Ptolemy, Regimontanus Purbach, and
Walther, the sextants and quadrants of Tycho Brahe, and the modifications
of these various instruments, the invention and use of which, from century
to century, bringing us at last to the telescopic age, or the days of
Lippershay, Jannsen, and Galileo.
[Illustration: FIG. 1.]
It would also be a most pleasant task to follow the evolution of our
subject in the new era of investigation ushered in by the invention of
that marvelous instrument, the telescope, followed closely by the work of
Kepler, Scheiner, Cassini, Huyghens, Newton, Digges, Nonius, Vernier,
Hall, Dollond, Herschel, Short, Bird, Ramsden, Troughton, Smeaton,
Fraunhofer, and a host of others, each of whom has contributed a noble
share in the elimination of sources of error, until to-day we are
satisfied only with units of measurement of the most exact and refined
nature. Although it would be pleasant to review the work of these past
masters, it is beyond the scope of the present paper, and even now I can
only hope to call your attention to one phase of this important subject.
For a number of years I have been practically interested in the subject of
the production of plane and curved surfaces particularly for optical
purposes, _i.e._, in the production of such surfaces free if possible from
all traces of error, and it will be pleasant to me if I shall be able to
add to the interest of this association by giving you some of my own
practical experience; and may I trust that it will be an incentive to all
engaged in kindred work _to do that work well?_
[Illustration: FIG. 2.]
In the production of a perfectly plane surface, there are many
difficulties to contend with, and it will not be possible in the limits of
this paper to discuss the methods of eliminating errors when found; but I
must content myself with giving a description of various methods of
detecting existing errors in the surfaces that are being worked, whether,
for instance, it be an error of concavity, convexity, periodic or local
error.
[Illustration: FIG. 3]
A very excellent method was devised by the celebrated Rosse, which is
frequently used at the present time; and those eminent workers, the Clarks
of Cambridge, use a modification of the Rosse method which in their hands
is productive of the very highest results. The device is very simple,
consisting of a telescope (_a_, Fig. 1) in which aberrations have been
well corrected, so that the focal plane of the objective is as sharp as
possible. This telescope is first directed to a distant object, preferably
a celestial one, and focused for parallel rays. The surface, _b_, to be
tested is now placed so that the reflected image of the same object,
whatever it may be, can be observed by the same telescope. It is evident
that if the surface be a true plane, its action upon the beam of light
that comes from the object will be simply to change its direction, but not
disturb or change it any other way, hence the reflected image of the
object should be seen by the telescope, _a_, without in any way changing
the original focus. If, however, the supposed plane surface proves to be
_convex_, the image will not be sharply defined in the telescope until the
eyepiece is moved _away_ from the object glass; while if the converse is
the case, and the supposed plane is concave, the eyepiece must now be
moved _toward_ the objective in order to obtain a sharp image, and the
amount of convexity or concavity may be known by the change in the focal
plane. If the surface has periodic or irregular errors, no sharp image can
be obtained, no matter how much the eyepiece may be moved in or out.
[Illustration: FIG. 4]
This test may be made still more delicate by using the observing
telescope, _a_, at as low an angle as possible, thereby bringing out with
still greater effect any error that may exist in the surface under
examination, and is the plan generally used by Alvan Clark & Sons. Another
and very excellent method is that illustrated in Fig. 2, in which a second
telescope, _b_, is introduced. In place of the eyepiece of this second
telescope, a diaphragm is introduced in which a number of small holes are
drilled, as in Fig. 2, _x_, or a slit is cut similar to the slit used in a
spectroscope as shown at _y_, same figure. The telescope, _a_, is now
focused very accurately on a celestial or other very distant object, and
the focus marked. The object glass of the telescope, _b_, is now placed
against and "square" with the object glass of telescope _a_, and on
looking through telescope a an image of the diaphragm with its holes or
the slit is seen. This diaphragm must now be moved until a sharp image is
seen in telescope _a_. The two telescopes are now mounted as in Fig. 2,
and the plate to be tested placed in front of the two telescopes as at
_c_. It is evident, as in the former case, that if the surface is a true
plane, the reflected image of the holes or slit thrown upon it by the
telescope, _b_, will be seen sharply defined in the telescope, _a_.
[Illustration: FIG. 5.]
If any error of convexity exists in the plate, the focal plane is
disturbed, and the eyepiece must be moved _out_. If the plate is concave,
it must be moved _in_ to obtain a sharp image. Irregular errors in the
plate or surface will produce a blurred or indistinct image, and, as in
the first instance, no amount of focusing will help matters. These methods
are both good, but are not satisfactory in the highest degree, and two or
three important factors bar the way to the very best results. One is that
the aberrations of the telescopes must be perfectly corrected, a very
difficult matter of itself, and requiring the highest skill of the
optician. Another, the fact that the human eye will accommodate itself to
small distances when setting the focus of the observing telescope. I have
frequently made experiments to find out how much this accommodation was in
my own case, and found it to amount to as much as 1/40 of an inch. This is
no doubt partly the fault of the telescopes themselves, but unless the eye
is rigorously educated in this work, it is apt to accommodate itself to a
small amount, and will invariably do so if there is a preconceived notion
or bias _in the direction of the accommodation_.
[Illustration: FIG. 6.]
Talking with Prof. C.A. Young a few months since on this subject, he
remarked that he noticed that the eye grew more exact in its demands as it
grew older, in regard to the focal point. A third and very serious
objection to the second method is caused by diffraction from the edges of
the holes or the slit. Let me explain this briefly. When light falls upon
a slit, such as we have here, it is turned out of its course; as the slit
has two edges, and the light that falls on either side is deflected both
right and left, the rays that cross from the right side of the slit toward
the left, and from the left side of the slit toward the right, produce
interference of the wave lengths, and when perfect interference occurs,
dark lines are seen. You can have a very pretty illustration of this by
cutting a fine slit in a card and holding it several inches from the eye,
when the dark lines caused by a total extinction of the light by
interference may be seen.
[Illustration: FIG. 7.]
If now you look toward the edge of a gas or lamp flame; you will see a
series of colored bands, that bring out the phenomenon of partial
interference. This experiment shows the difficulty in obtaining a perfect
focus of the holes or the slit in the diaphragm, as the interference
fringes are always more or less annoying. Notwithstanding these defects of
the two systems I have mentioned, in the hands of the practical workman
they are productive of very good results, and very many excellent surfaces
have been made by their use, and we are not justified in ignoring them,
because they are the stepping stones to lead us on to better ones. In my
early work Dr. Draper suggested a very excellent plan for testing a flat
surface, which I briefly describe. It is a well known truth that, if an
artificial star is placed in the exact center of curvature of a truly
spherical mirror, and an eyepiece be used to examine the image close
beside the source of light, the star will be sharply defined, and will
bear very high magnification. If the eyepiece is now drawn toward the
observer, the star disk begins to expand; and if the mirror be a truly
spherical one, the expanded disk will be equally illuminated, except the
outer edge, which usually shows two or more light and dark rings, due to
diffraction, as already explained.
[Illustration: FIG. 8.]
Now if we push the eyepiece toward the mirror the same distance on the
opposite side of the true focal plane, precisely the same appearance will
be noted in the expanded star disk. If we now place our plane surface any
where in the path of the rays from the great mirror, we should have
identically the same phenomena repeated. Of course it is presumed, and is
necessary, that the plane mirror shall be much less in area than the
spherical mirror, else the beam of light from the artificial star will be
shut off, yet I may here say that any one part of a truly spherical mirror
will act just as well as the whole surface, there being of course a loss
of light according to the area of the mirror shut off.
This principle is illustrated in Fig. 3, where _a_ is the spherical
mirror, _b_ the source of light, _c_ the eyepiece as used when the plane
is not interposed, _d_ the plane introduced into the path at an angle of
45° to the central beam, and _e_ the position of eyepiece when used the
with the plane. When the plane is not in the way, the converging beam goes
back to the eyepiece, _c_. When the plane, _d_, is introduced, the beam is
turned at a right angle, and if it is a perfect surface, not only does the
focal plane remain exactly of the same length, but the expanded star
disks, are similar on either side of the focal plane.
[Illustration: FIG. 9.]
I might go on to elaborate this method, to show how it may be made still
more exact, but as it will come under the discussion of spherical
surfaces, I will leave it for the present. Unfortunately for this process,
it demands a large truly spherical surface, which is just as difficult of
attainment as any form of regular surface. We come now to an instrument
that does not depend upon optical means for detecting errors of surface,
namely, the spherometer, which as the name would indicate means sphere
measure, but it is about as well adapted for plane as it is for spherical
work, and Prof. Harkness has been, using one for some time past in
determining the errors of the plane mirrors used in the transit of Venus
photographic instruments. At the meeting of the American Association of
Science in Philadelphia, there was quite a discussion as to the relative
merits of the spherometer test and another form which I shall
presently mention, Prof. Harkness claiming that he could, by the
use of the spherometer, detect errors bordering closely on one
five-hundred-thousandth of an inch. Some physicists express doubt on this,
but Prof. Harkness has no doubt worked with very sensitive instruments,
and over very small areas at one time.
I have not had occasion to use this instrument in my own work, as a more
simple, delicate, and efficient method was at my command, but for one
measurement of convex surfaces I know of nothing that can take its place.
I will briefly describe the method of using it.
[Illustration: FIG. 10.]
The usual form of the instrument is shown in Fig. 4; _a_ is a steel screw
working in the nut of the stout tripod frame, _b_; _c c c_ are three legs
with carefully prepared points; _d_ is a divided standard to read the
whole number of revolutions of the screw, _a_, the edge of which also
serves the purpose of a pointer to read off the division on the top of the
milled head, _e_. Still further refinement may be had by placing a vernier
here. To measure a plane or curved surface with this instrument, a perfect
plane or perfect spherical surface of known radius must be used to
determine the zero point of the division. Taking for granted that we have
this standard plate, the spherometer is placed upon it, and the readings
of the divided head and indicator, _d_, noted when the point of the screw,
_a_, just touches the surface, _f_. Herein, however, lies the great
difficulty in using this instrument, _i.e._, to know the exact instant of
contact of the point of screw, _a_, on the surface, _f_. Many devices have
been added to the spherometer to make it as sensitive as possible, such as
the contact level, the electric contact, and the compound lever contact.
The latter is probably the best, and is made essentially as in Fig. 5.
[Illustration: FIG. 11.]
I am indebted for this plan to Dr. Alfred Mayer. As in the previous
figure, _a_ is the screw; this screw is bored out, and a central steel pin
turned to fit resting on a shoulder at _c_. The end of _d_ projects below
the screw, _a_, and the end, _e_, projects above the milled head, and the
knife edge or pivot point rests against the lever, _f_, which in turn
rests against the long lever, _g_, the point, _h_, of which moves along
the division at _j_. It is evident that if the point of the pin just
touches the plate, no movement of the index lever, _g_, will be seen; but
if any pressure be applied, the lever will move through a multiplied arc,
owing to the short fulcri of the two levers. Notwithstanding all these
precautions, we must also take into account the flexure of the material,
the elasticity of the points of contact, and other idiosyncrasies, and you
can readily see that practice alone in an instrument so delicate will
bring about the very best results. Dr. Alfred Mayer's method of getting
over the great difficulty of knowing when all four points are in contact
is quite simple. The standard plate is set on the box, _g_, Fig. 4, which
acts as a resonater. The screw, _a_, is brought down until it touches the
plate. When the pressure of the screw is enough to lift off either or all
of the legs, and the plate is gently tapped with the finger, a _rattle_ is
heard, which is the tell-tale of imperfect contact of all the points. The
screw is now reversed gently and slowly until the _moment_ the rattle
ceases, and then the reading is taken. Here the sense of hearing is
brought into play. This is also the case when the electric contact is
used. This is so arranged that the instant of touching of the point of
screw, _a_, completes the electric circuit, in which an electromagnet of
short thick wire is placed. At the moment of contact, or perhaps a little
before contact, the bell rings, and the turning of the screw must be
instantly stopped. Here are several elements that must be remembered.
First, it takes time to set the bell ringing, time for the sound to pass
to the ear, time for the sensation to be carried to the brain, time for
the brain to send word to the hand to cease turning the screw, and, if you
please, it takes time for the hand to stop. You may say, of what use are
such refinements? I may reply, what use is there in trying to do anything
the very best it can be done? If our investigation of nature's profound
mysteries can be partially solved with good instrumental means, what is
the result if we have better ones placed in our hands, and what, we ask,
if the _best_ are given to the physicist? We have only to compare the
telescope of Galileo, the prism of Newton, the pile of Volta, and what was
done with them, to the marvelous work of the telescope, spectroscope, and
dynamo of to-day. But I must proceed. It will be recognized that in
working with the spherometer, only the points in actual contact can be
measured at one time, for you may see by Fig. 6 that the four points, _a a
a a_, may all be normal to a true plane, and yet errors of depression, as
at _e_, or elevation, as at _b_, exist between them, so that the
instrument must be used over every available part of the surface if it is
to be tested rigorously. As to how exact this method is I cannot say from
actual experience, as in my work I have had recourse to other methods that
I shall describe. I have already quoted you the words of Prof. Harkness.
Dr. Hastings, whose practical as well as theoretical knowledge is of the
most critical character, tells me that he considers it quite easy to
measure to 1/80000 of an inch with the ordinary form of instrument. Here
is a very fine spherometer that Dr. Hastings works with from time to time,
and which he calls his standard spherometer. It is delicately made, its
screw being 50 to the inch, or more exactly 0.01998 inch, or within
2/100000 of being 1/50 of an inch pitch. The principal screw has a point
which is itself an independent screw, that was put in to investigate the
errors of the main screw, but it was found that the error of this screw
was not as much as the 0.00001 of an inch. The head is divided into two
hundred parts, and by estimation can be read to 1/100000 of an inch. Its
constants are known, and it may be understood that it would not do to
handle it very roughly. I could dwell here longer on this fascinating
subject, but must haste. I may add that if this spherometer is placed on a
plate of glass and exact contact obtained, and then removed, and the hand
held over the plate without touching it, the difference in the temperature
of the glass and that of the hand would be sufficient to distort the
surface enough to be readily recognized by the spherometer when replaced.
Any one desiring to investigate this subject further will find it fully
discussed in that splendid series of papers by Dr. Alfred Mayer on the
minute measurements of modern science published in SCIENTIFIC AMERICAN
SUPPLEMENTS, to which I was indebted years ago for most valuable
information, as well as to most encouraging words from Prof. Thurston,
whom you all so well and favorably know. I now invite your attention to
the method for testing the flat surfaces on which Prof. Rowland rules the
beautiful diffraction gratings now so well known over the scientific
world, as also other plane surfaces for heliostats, etc., etc. I am now
approaching the border land of what may be called the abstruse in science,
in which I humbly acknowledge it would take a vast volume to contain all I
don't know; yet I hope to make plain to you this most beautiful and
accurate method, and for fear I may forget to give due credit, I will say
that I am indebted to Dr. Hastings for it, with whom it was an original
discovery, though he told me he afterward found it had been in use by
Steinheil, the celebrated optician of Munich. The principle was discovered
by the immortal Newton, and it shows how much can be made of the ordinary
phenomena seen in our every-day life when placed in the hands of the
investigator. We have all seen the beautiful play of colors on the soap
bubble, or when the drop of oil spreads over the surface of the water.
Place a lens of long curvature on a piece of plane polished glass, and,
looking at it obliquely, a black central spot is seen with rings of
various width and color surrounding it. If the lens is a true curve, and
the glass beneath it a true plane, these rings of color will be perfectly
concentric and arranged in regular decreasing intervals. This apparatus is
known as Newton's color glass, because he not only measured the phenomena,
but established the laws of the appearances presented. I will now endeavor
to explain the general principle by which this phenomenon is utilized in
the testing of plane surfaces. Suppose that we place on the lower plate,
lenses of constantly increasing curvature until that curvature becomes
nil, or in other words a true plane. The rings of color will constantly
increase in width as the curvature of the lens increases, until at last
one color alone is seen over the whole surface, provided, however, the
same angle of observation be maintained, and provided further that the
film of air between the glasses is of absolutely the same relative
thickness throughout. I say the film of air, for I presume that it would
be utterly impossible to exclude particles of dust so that absolute
contact could take place. Early physicists maintained that absolute
molecular contact was impossible, and that the central separation of the
glasses in Newton's experiment was 1/250,000 of an inch, but Sir Wm.
Thomson has shown that the separation is caused by shreds or particles of
dust. However, if this separation is equal throughout, we have the
phenomena as described; but if the dust particles are thicker under one
side than the other, our phenomena will change to broad parallel bands as
in Fig. 8, the broader the bands the nearer the absolute parallelism of
the plates. In Fig. 7 let _a_ and _b_ represent the two plates we are
testing. Rays of white light, _c_, falling upon the upper surface of plate
_a_, are partially reflected off in the direction of rays _d_, but as
these rays do not concern us now, I have not sketched them. Part of the
light passes on through the upper plate, where it is bent out of its
course somewhat, and, falling upon the _lower_ surface of the upper plate,
some of this light is again reflected toward the eye at _d_. As some of
the light passes through the upper plate, and, passing through the film of
air between the plates, falling on the upper surface of the _lower_ one,
this in turn is reflected; but as the light that falls on this surface has
had to traverse the film of air _twice_, it is retarded by a certain
number of half or whole wave-lengths, and the beautiful phenomena of
interference take place, some of the colors of white light being
obliterated, while others come to the eye. When the position of the eye
changes, the color is seen to change. I have not time to dwell further on
this part of my subject, which is discussed in most advanced works on
physics, and especially well described in Dr. Eugene Lommel's work on "The
Nature of Light." I remarked that if the two surfaces were perfectly
_plane_, there would be one color seen, or else colors of the first or
second order would arrange themselves in broad parallel bands, but this
would also take place in plates of slight curvature, for the requirement
is, as I said, a film of air of equal thickness throughout. You can see at
once that this condition could be obtained in a perfect convex surface
fitting a perfect concave of the same radius. Fortunately we have a check
to guard against this error. To produce a perfect plane, _three surfaces
must_ be worked together, unless we have a true plane to commence with;
but to make this true plane by this method we _must_ work three together,
and if each one comes up to the demands of this most rigorous test, we may
rest assured that we have attained a degree of accuracy almost beyond
human conception. Let me illustrate. Suppose we have plates 1, 2, and 3,
Fig. 11. Suppose 1 and 2 to be accurately convex and 3 accurately concave,
of the same radius. Now it is evident that 3 will exactly fit 1 and 2, and
that 1 and 2 will separately fit No. 3, _but_ when 1 and 2 are placed
together, they will only touch in the center, and there is no possible
way to make three plates coincide when they are alternately tested upon
one another than to make _perfect planes_ out of them. As it is difficult
to see the colors well on metal surfaces, a one-colored light is used,
such as the sodium flame, which gives to the eye in our test, dark and
bright bands instead of colored ones. When these plates are worked and
tested upon one another until they all present the same appearance, one
may be reserved for a test plate for future use. Here is a small test
plate made by the celebrated Steinheil, and here two made by myself, and I
may be pardoned in saying that I was much gratified to find the
coincidence so nearly perfect that the limiting error is much less than
0.00001 of an inch. My assistant, with but a few months' experience, has
made quite as accurate plates. It is necessary of course to have a glass
plate to test the metal plates, as the upper plate _must_ be transparent.
So far we have been dealing with perfect surfaces. Let us now see what
shall occur in surfaces that are not plane. Suppose we now have our
perfect test plate, and it is laid on a plate that has a compound error,
say depressed at center and edge and high between these points. If this
error is regular, the central bands arrange themselves as in Fig. 9. You
may now ask, how are we to know what sort of surface we have? A ready
solution is at hand. The bands _always travel in the direction of the
thickest film of air_, hence on lowering the eye, if the convex edge of
the bands travel in the direction of the arrow, we are absolutely certain
that that part of the surface being tested is convex, while if, as in the
central part of the bands, the concave edges advance, we know that part is
hollow or too low. Furthermore, any small error will be rigorously
detected, with astonishing clearness, and one of the grandest qualities of
this test is the absence of "personal equation;" for, given a perfect test
plate, _it won't lie_, neither will it exaggerate. I say, won't lie, but I
must guard this by saying that the plates must coincide absolutely in
temperature, and the touch of the finger, the heat of the hand, or any
disturbance whatever will vitiate the results of this lovely process; but
more of that at a future time. If our surface is plane to within a short
distance of the edge, and is there overcorrected, or convex, the test
shows it, as in Fig. 10. If the whole surface is regularly convex, then
concentric rings of a breadth determined by the approach to a perfect
plane are seen. If concave, a similar phenomenon is exhibited, except in
the case of the convex, the broader rings are near the center, while in
the concave they are nearer the edge. In lowering the eye while observing
the plates, the rings of the convex plate will advance outward, those of
the concave inward. It may be asked by the mechanician, Can this method be
used for testing our surface plates? I answer that I have found the
scraped surface of iron bright enough to test by sodium light. My
assistant in the machine work scraped three 8 inch plates that were tested
by this method and found to be very excellent, though it must be evident
that a single cut of the scraper would change the spot over which it
passed so much as to entirely change the appearance there, but I found I
could use the test to get the general outline of the surface under process
of correction. These iron plates, I would say, are simply used for
preliminary formation of polishers. I may have something to say on the
question of surface plates in the future, as I have made some interesting
studies on the subject. I must now bring this paper to a close, although I
had intended including some interesting studies of curved surfaces. There
is, however, matter enough in that subject of itself, especially when we
connect it with the idiosyncrasies of the material we have to deal with, a
vital part of the subject that I have not touched upon in the present
paper. You may now inquire, How critical is this "color test"? To answer
this I fear I shall trench upon forbidden grounds, but I call to my help
the words of one of our best American physicists, and I quote from a
letter in which he says by combined calculation and experiment I have
found the limiting error for white light to be 1/50000000 of an inch, and
for Na or sodium light about fifty times greater, or less than 1/800000 of
an inch. Dr. Alfred Mayer estimated and demonstrated by actual experiment
that the smallest black spot on a white ground visible to the naked eye is
about 1/800 of an inch at the distance of normal vision, namely, 10
inches, and that a line, which of course has the element of extension,
1/5000 of an inch in thickness could be seen. In our delicate "color test"
we may decrease the diameter of our black spot a thousand times and still
its perception is possible by the aid of our monochromatic light, and we
may diminish our line ten thousand times, yet find it just perceivable on
the border land of our test by white light. Do not presume I am so foolish
as to even think that the human hand, directed by the human brain, can
ever work the material at his command to such a high standard of
exactness. No; from the very nature of the material we have to work with,
we are forbidden even to hope for such an achievement; and could it be
possible that, through some stroke of good fortune, we could attain this
high ideal, it would be but for a moment, as from the very nature of our
environment it would be but an ignis fatuus. There is, however, to the
earnest mind a delight in having a high model of excellence, for as our
model is so will our work approximate; and although we may go on
approximating _our_ ideal forever, we can never hope to reach that which
has been set for us by the great Master Workman.
* * * * *
[JOURNAL OF GAS LIGHTING.]
PHOTOMETRICAL STANDARDS.
In carrying out a series of photometrical experiments lately, I found that
it was a matter of considerable difficulty to keep the flames of the
standard candles always at their proper distance from the light to be
measured, because the wick was continually changing its position (of
course carrying the flame with it), and thus practically lengthening or
shortening the scale of the photometer, according as the flame was carried
nearer to or farther from the light at the other end of the scale. In
order, therefore, to obtain a correct idea of the extent to which this
variation of the position of the wick might influence the readings of the
photometer scale, I took a continuous number of photographs of the flame
of a candle while it was burning in a room quite free from draught; no
other person being in it during the experiment except a photographer, who
placed sensitive dry plates in a firmly fixed camera, and changed them
after an exposure of 30 seconds. In doing this he was careful to keep
close to the camera, and disturb the air of the room as little as
possible. In front of the candle a plumb-line was suspended, and remained
immovable over its center during the whole operation. The candle was
allowed to get itself into a normal state of burning, and then the wick
was aligned, as shown in the photographs Nos. 1 and 2, after which it was
left to itself.
[Illustration: VARIATION IN PHOTOMETRICAL STANDARDS.]
With these photographs (represented in the cuts) I beg to hand you
full-sized drawings of the scales of a 100 inch Evans and a 60 inch
Letheby photometer, in order to give your readers an opportunity of
estimating for themselves the effect which such variations from the true
distance between the standard light and that to be measured, as shown in
this series of photographs, must exercise on photometrical observations
made by the aid of either of the instruments named.
W. SUGG.
* * * * *
BLEACHING OR DYEING-YARNS AND GOODS IN VACUO.
[Illustration]
Many attempts have been made to facilitate the penetration of textile
fabrics by the dyeing and bleaching solutions, with which they require to
be treated, by carrying out the treatment in vacuo, _i.e._, in such
apparatus as shall allow of the air being withdrawn. The apparatus shown
in the annexed engraving--Austrian Pat. Jan. 15, 1884--although not
essentially different from those already in use, embodies, the _Journal of
the Society of Chemical Industry_ says, some important improvements in
detail. It consists of a drum A, the sides of which are constructed of
stout netting, carried on a vertical axis working through a stuffing-box,
which is fitted in the bottom of the outer or containing vessel or keir B.
The air can be exhausted from B by means of an air pump. A contains a
central division P, also constructed of netting, into which is inserted
the extremity of the tube R, after being twice bent at a right angle. P is
also in direct connection with the efflux tube E, E and R serving to
convey the dye or bleach solutions to and from the reservoir C. The
combination of the rotary motion communicated to A, which contains the
goods to be dyed or bleached, with the very thorough penetration and
circulation of the liquids effected by means of the vacuum established in
B, is found to be eminently favorable to the rapidity and evenness of the
dye or bleach.
* * * * *
ON THE MOULDING OF PORCELAIN.
By CHAS. LAUTH.
The operation of moulding presents numerous advantages over other methods
of shaping porcelain, for by this process we avoid irregularities of form,
twisting, and visible seams, and can manufacture thin pieces, as well as
pieces of large dimensions, of a purity of form that it is impossible to
obtain otherwise.
The method of moulding small objects has been described with sufficient
detail in technical works, but such is not the case with regard to large
ones, and for this reason it will be of interest to quote some practical
observations from a note that has been sent me by Mr. Constantine Renard,
who, for several years, has had the superintendence of the moulding rooms
of the Sevres works.
The process of moulding consists in pouring porcelain paste, thinned with
water, into very dry plaster moulds. This mixture gradually hardens
against the porous sides with which it is in contact, and, when the
thickness of the hardened layer is judged sufficient, the mould is emptied
by inverting it. The excess of the liquid paste is thus eliminated, while
the thicker parts remain adherent to the plaster. Shortly afterward, the
absorption of the water continuing, the paste so shrinks in drying as to
allow the object to detach itself from the mould. As may be seen, nothing
is simpler when it concerns pieces of small dimensions; but the same is
not the case when we have to mould a large one. In this case we cannot get
rid of the liquid paste by turning the mould upside down, because of the
latter's size, and, on another hand, it is necessary to take special
precautions against the subsidence of the paste. Recourse is therefore had
to another method. In the first place, an aperture is formed in the lower
part of the mould through which the liquid may flow at the desired moment.
Afterward, in order to prevent the solidified but still slightly soft
paste from settling under its own weight at this moment, it is supported
by directing a current of compressed air into the mould, or, through
atmospheric pressure, by forming a vacuum in the metallic jacket in which
the mould is inclosed.
The history and description of these processes have been several times
given, and I shall therefore not dwell upon them, but shall at once
proceed to make known the new points that Mr. Renard has communicated to
me.
The first point to which it is well to direct the manufacturer's attention
is the preparation of the plaster moulds. When it concerns an object of
large dimensions, of a vase a yard in height, for example, the moulder is
obliged to cut the form or core horizontally into three parts, each of
which is moulded separately. To this effect, it is placed upon a core
frame and surrounded with a cylinder of sheet zinc. The workman pours the
plaster into the space between the latter and the core, and, while doing
so, must stir the mass very rapidly with a stick, so that at the moment
the plaster sets, it shall be as homogeneous as possible. In spite of such
precautions, it is impossible to prevent the densest parts of the plaster
from depositing first, through the action of gravity. These will naturally
precipitate upon the table or upon the slanting sides of the core, and the
mould will therefore present great inequalities as regards porosity. Since
this defect exists in each of the pieces that have been prepared in
succession, it will be seen that when they come to be superposed for the
moulding of the piece, the mould as a whole will be formed of zones of
different porosities, which will absorb water from the paste unequally.
Farther along we shall see the inconveniences that result from this, and
the manner of avoiding them.
[Illustration: FIG. 1]
The mould, when finished, is dried in a stove. Under such circumstances it
often happens that there forms upon the surface of the plaster a hard
crust which, although it is of no importance as regards the outside of the
mould, is prejudicial to the interior because it considerably diminishes
its absorbing power. This trouble may be avoided by coating the surfaces
that it is necessary to preserve with clear liquid paste; but Mr. Renard
advises that the mould be closed hermetically, so that the interior shall
be kept from contact with warm air. In this way it is possible to prevent
the plaster from hardening, as a result of too quick a desiccation. I now
come to the operation of moulding. In the very first place, it is
necessary to examine whether it is well to adopt the arrangement by
pressure of air or by vacuum. The form of the objects will determine the
choice. A very open piece, like a bowl, must be moulded by vacuum, on
account of the difficulty of holding the closing disk in place if it be of
very large dimensions. The same is the case with large vases of wood form.
On the contrary, an elongated piece tapering from above is more easily
moulded by pressure of the air, as are also ovoid vessels 16 to 20 inches
in height. In any case it must not be forgotten that the operation by
vacuum should be preferred every time the form of the objects is adapted
to it, because this process permits of following and directing the drying,
while with pressure it is impossible to see anything when once the
apparatus is closed.
[Illustration: FIG. 2.]
_Moulding by Pressure of the Air._--The plaster mould having been put in
place upon the mould board, and the liquid paste having been long and
thoroughly stirred in order to make it homogeneous, and get rid of the air
bubbles, we open the cock that puts the paste reservoir in communication
with the lower part of the mould, care having been taken beforehand to
pour a few pints of water into the bottom of the mould. The paste in
ascending pushes this water ahead of it, and this slightly wets the
plaster and makes the paste rise regularly. When the mould is entirely
filled, the paste is still allowed to flow until it slightly exceeds the
upper level, and, spreading out over the entire thickness of the plaster,
forms a sort of thick flange. The absorption of the liquid begins almost
immediately, and, consequently, the level lowers. A new quantity of paste
is introduced, and we continue thus, in regulating its flow so as to keep
the mould always full. This operation is prolonged until the layer is
judged to be sufficiently thick, this depending upon the dimensions, form,
or construction of the vessel. The operation may take from one to five
hours.
The desired thickness having been obtained, it becomes a question of
allowing the paste to descend and at the same time to support the piece by
air pressure. The flange spoken of above is quickly cut, and the paste is
made to rise again for the last time, in order to form a new flange, but
one that this time will be extremely thin; then a perforated disk designed
for forming the top joint, and acting as a conduit for the air, is placed
upon the mould. This disk is fastened down with a screw press, and when
the apparatus is thus arranged the eduction cock is opened, and the air
pump maneuvered.
If the flange did not exist, the air would enter between the mould and the
piece at the first strokes of the piston, and the piece would be
inevitably broken. Its object, then, is to form a hermetical joint,
although it must at the same time present but a slight resistance, since,
as soon as the liquid paste has flowed out, the piece begins to shrink,
and it is necessary that at the first movement downward it shall be able
to disengage itself, since it would otherwise crack.
As soon as the piece begins to detach itself from the mould the air enters
the apparatus, and the pressure gauge connected with the air pump begins
to lower. It is then necessary, without a moment's loss of time, to remove
the screw press, the disk, and the upper part of the mould itself, in
order to facilitate as much as possible the contraction of the piece.
Finally, an hour or an hour and a half later, it is necessary to remove
the lower part of the mould, this being done in supporting the entire
affair by the middle. The piece and what remains of the mould are, in
reality, suspended in the air. All these preparations are designed to
prevent cracking.
_Moulding by Vacuum._--The operation by vacuum follows the same phases as
those just described. It is well, in order to have a very even surface,
not to form a vacuum until about three hours after the paste has been made
to ascend. Without such a precaution the imperfections in the mould will
be shown on the surface of the object by undulations that are
irremediable.
The first flange or vein must be preserved, and it is cut off at the
moment the piece is detached.
Moulding by vacuum, aside from the advantages noted above, permits of
giving the pieces a greater thickness than is obtained in the pressure
process. According to Mr. Renard, when it is desired to exceed one inch at
the base of the piece (the maximum thickness usually obtained), the
operation is as follows: The piece is moulded normally, and it is
supported by a vacuum; but, at the moment at which, under ordinary
circumstances, it would be detached, the paste is made to ascend a second
time, when the first layer (already thick and dry) acts as a sort of
supplementary mould, and permits of increasing the thickness by about 2/5
of an inch. The piece is held, as at first, by vacuum, and the paste is
introduced again until the desired thickness is obtained.
Whatever be the care taken, accidents are frequent in both processes. They
are due, in general, to the irregular contraction of the pieces, caused by
a want of homogeneousness in the plaster of the moulds. In fact, as the
absorption of the water does not proceed regularly over the entire surface
of the piece, zones of dry paste are found in contact with others that are
still soft, and hence the formation of folds, and finally the cracking and
breaking of the piece. The joints of the moulds are also a cause of
frequent loss, on account of the marks that they leave, and that injure
the beauty of the form as well as the purity of the profile.
Mr. Renard has devised a remedy for all such inconveniences. He takes
unglazed muslin, cuts it into strips, and, before beginning operations,
fixes it with a little liquid paste to the interior of the mould. This
light fabric in no wise prevents the absorption of the water, and so the
operation goes on as usual; but, at the moment of contraction, the piece
of porcelain being, so to speak, supported by the muslin, comes put of the
mould more easily and with extreme regularity. Under such circumstances
all trace of the joint disappears, the imperfections in the mould are
unattended with danger, and the largest pieces are moulded with entire
safety. In a word, we have here a very important improvement in the
process of moulding. The use of muslin is to be recommended, not only in
the manufacture of vases, but also in the difficult preparation of large
porcelain plates. It is likewise advantageous in the moulding of certain
pieces of sculpture that are not very delicate, and, finally, it is very
useful when we have to do with a damaged mould, which, instead of being
repaired with plaster, can be fixed with well ground wet sand covered with
a strip of muslin.
_Drying of the Moulded Pieces._--When the moulded pieces become of a
proper consistency in the mould, they are exposed to the air and then
taken to the drying room. But, as with plaster, the surface of the paste
dries very quickly, and this inconvenience (which amounts to nothing in
pieces that are to be polished) is very great in pieces that carry
ornaments in relief, since the finishing of these is much more difficult,
the hardened paste works badly, and frequently flakes off. In order to
remedy this inconvenience, it suffices to dust the places to be preserved
with powdered dry paste.--_Revue Industrielle._
* * * * *
PHOTO-TRICYCLE APPARATUS.
[Illustration: A PHOTO-TRICYCLE APPARATUS.]
This consists of a portable folding camera, with screw focusing
arrangement, swing back, and an adapter frame placed in the position of
the focus screen, allowing the dark slide to be inserted so as to give the
horizontal or vertical position to the dry plate when in the camera. To
the front and base-board a brass swiveled side bar, made collapsible by
means of a center slot, is attached by hinges, and this renders the camera
rigid when open or secure when closed. The base-board is supported on a
brass plate within which is inserted a ball-and-socket (or universal joint
in a new form), permitting the camera to be tilted to any necessary angle,
and fixed in such position at will. The whole apparatus is mounted upon a
brass telescopic draw-stand, which, by means of clamps, is attached to the
steering handle or other convenient part of the tricycle, preferably the
form made by Messrs. Rudge & Co., of Coventry, represented in the
cut.--_Photo. News._
* * * * *
A PHOTO PRINTING LIGHT.
[Illustration]
A printing frame is placed in the carrier, and exposed to the light of a
gas burner kept at a fixed distance, behind which is a spherical
reflector. The same frame may be used for other purposes.-_Photographic
News._
* * * * *
A NEW ACTINOMETER.
A selenium actinometer has been described in the _Comptes Rendus_ in a
communication from M. Morize, of Rio de Janeiro. The instrument is used to
measure the actinic power of sunlight when the sun is at various
altitudes; but the same principle is applicable to other light sources.
The sensitive part of the apparatus consists of a cylinder formed of 38
disks of copper, isolated from each other by as many disks of mica. The
latter being of smaller diameter than the copper disks, the annular spaces
between the two are filled with selenium, by the simple process of rubbing
a stick of this substance over the edges, and afterward gently warming.
The selenium then presents a grayish appearance, and is ready for use.
Connection is made by conductors, on opposite sides, with the odd and even
numbers of the disks, which diminishes the resistance of the selenium. The
cylinder thus formed is insulated by glass supports in the inside of a
vacuum tube, for the purpose of preserving it from the disturbing
influence of dark rays. The whole is placed upon a stand, and shielded
from reflected light, but fully exposed to that which is to be measured
for actinic intensity. If now a constant current of electricity is passed
through the apparatus, as indicated by a galvanometer, the variations of
the latter will show the effect produced upon the selenium. A scale must
be prepared, with the zero point at the greatest possible resistance of
the selenium, which corresponds with absolute darkness. The greatest
effect of the light would be to annul the resistance of the selenium.
Consequently, the cylinder must be withdrawn from the circuit to represent
this effect; and the maximum deviation of the galvanometer is then to be
observed, and marked 100. By dividing the range of the galvanometer thus
obtained into 100 equal parts, the requisite actinometric scale will be
established. In practice, the Clamond battery is used to supply the
constant current required.
* * * * *
ASTRONOMICAL PHOTOGRAPHY.
During the last few years, or rather decades of years, it has become
rather a trite saying that to advance far in any branch of physical
research a fair proficiency in no inconsiderable number of the sister
sciences is an absolute necessity. But if this is true in general, none, I
think, will question the assertion that a proficient in any of the
physical sciences must be fairly conversant with photography as a science,
or at least as an art. If we take for example a science which has of late
years made rapid strides both in Europe and America, the science of
astronomy, we shall not have far to go to find convincing proof that a
great portion of the best work that is being done by its votaries is
effected by the aid of photography. One eminent astronomer has quite
lately gone so far as to declare that we no longer require observers of
the heavens, but that their place can be better supplied by the gelatine
plate of the photographer; and his words have been echoed by others not
less able than himself. "Abolish the observer, and substitute the
sensitive plate," is a sensational form of expressing the revolution in
observational astronomy that is taking place under our eyes; but, although
it suggests a vast amount of truth, it might leave upon the mind an
exaggerated impression inimical to the best interests of science.
The award of the highest distinction in astronomy, the gold medal of the
Royal Astronomical Society, two years in succession, to those who have
been most successful in celestial photography is no doubtful sign of the
great value attached to such work. Last year it was Mr. Common who
received the highest testimony of the merit due to his splendid
photographs of the nebula of Orion; and this year Dr. Huggins, who has
drawn much attention to celestial photography, by his successful attempts
to picture the solar corona in full daylight, has received a similar
acknowledgment of his labors in photographing the spectra of stars and
comets and nebulæ.
An adequate idea of the progress astronomy is now making by aid of
photography can only be formed by a comprehensive view of all that is
being at present attempted; but a rapid glance at some of the work may
prepare the way for a more thorough investigation. A few years since, the
astronomers who had advanced their science by aid of photography were few
in number, and their results are soon enumerated. Some good pictures of
the solar corona taken during solar eclipses, a series or two of sun-spot
photographs, and a very limited number of successful attempts made upon
the moon, and planets, and star clusters, were all the fruits of their
labors. But now each month we learn of some new and efficient laborer in
this field, which gives promise of so rich a harvest.
Each day the sun is photographed at Greenwich, at South Kensington, in
India, and at the Physical Observatory of Potsdam, and thus a sure record
is obtained of all the spots upon its surface, which may serve for the
study of the periodicity of its changes, and for their probable connection
with the important phenomena of terrestrial magnetism and meteorology. In
France the splendid sun-pictures obtained by Dr. Janssen at the Physical
Observatory of Meudon have thrown into the shade all other attempts at a
photographic study of the most delicate features of the solar surface.
Dr. Huggins has shown that it is possible to obtain a daily photographic
record of the solar prominences, and only lately he has secured results
that justified a special expedition to the Alps to photograph the sun's
corona, and he has now moved the Admiralty to grant a subsidy to Dr. Gill,
the government astronomer at the Cape, by aid of which Mr. Woods can carry
on the experiments that were so encouraging last summer in Switzerland.
We may, then, reasonably hope to obtain before long a daily picture of the
sun and a photographic record of its prominences, and even of a certain
portion of the solar corona; but the precious moments of each solar
eclipse will always be invaluable for picturing those wondrous details in
the corona that are now shown us by photography, and which can be obtained
by photography alone.
Again, how very much is to be learnt in solar physics from the marvelous
photographs of the sun's spectrum exhibited last summer by Professor
Rowland; photographs that show as many as one hundred and fifty lines
between H and K, and which he is still laboring to improve! The extension,
too, of the visible solar spectrum into the ultra-violet by Corun,
Mascart, and others, adds much to our knowledge of the sun; while the
photographs of Abney in the ultrared increase our information in a
direction less expected and certainly less easy of attainment. Both these
extensions we find most ably utilized in the recent discussion of the very
interesting photographs of the spectra of the prominences and of the
corona taken during the total eclipse of May 18, 1882; and the
photographic results of this eclipse afford ample proof that we can not
only obtain pictures of the corona by photography that it would be
impossible otherwise to procure, but also that in a few seconds
information concerning the nature of the solar atmosphere may be furnished
by photography that it would otherwise take centuries to accumulate, even
under the most favorable circumstances.
The advantages to be gained by accurate photographs of the moon and
planets, that will permit great enlargements, are too obvious to call for
lengthened notice in such a rapid sketch as the present; for it is
principally in the observation of details that the eye cannot grasp with
the required delicacy, or with sufficient rapidity, that photography is so
essential for rapid and sure progress.
Like the sketches of a solar eclipse, the drawings that are made of
comets, and still more of nebulæ, even by the most accomplished artists,
are all, to say the least, open to doubt in their delicate details. And
the truth of this is so obvious, that it is the expressed opinion of an
able astronomer that a single photograph of the nebula of Orion, taken by
Mr. Common, would be of more value to posterity than the collective
drawings of this interesting object so carefully made by Rosse, Bond,
Secchi, and so many others.
Another most important branch of astronomy, that is receiving very great
attention at present, is the mapping of the starry heavens; and herein
photography will perhaps do its best work for the astronomer. The trial
star map by the brothers Henry, of a portion of the Milky Way, which they
felt unable to observe satisfactorily by the ordinary methods, is so near
absolute perfection that it alone proves the immense superiority of the
photographic method in the formation of star maps. Fortunately this
subject, which is as vast as it is fundamental, is being taken up
vigorously. The Henries are producing a special lens for the work; Mr.
Grubb is constructing a special Cassgrain reflector for Mr. Roberts of
Maghull; and the Admiralty have instructed Mr. Woods to make this part of
his work at the Cape Observatory, under the able direction of Dr. Gill.
Besides star maps, clusters, too, and special portions of the heavens are
being photographed by the Rev. T.E. Espin, of West Kirby; and such
pictures will be of the greatest value, not only in fixing the position at
a given date, but also aiding in the determination of magnitude, color,
variability, proper motion, and even of the orbits of double and multiple
stars, and the possible discovery of new planets and telescopic comets.
Such are some of the many branches of astronomy that are receiving the
most valuable aid at present from photography; but the very value of the
gift that is bestowed should make exaggeration an impossibility.
Photography can well afford to be generous, but it must first be just, in
its estimate of the work that has still to be done in astronomy
independently of its aid; and although the older science points with just
pride to what is being done for her by her younger sister, still she must
not forget that now, as in the future, she must depend largely for her
progress, not only on the skill of the photographer and the mathematician,
but also on the trained eye and ear and hand of her own indefatigable
observers.--_S.J. Perry, S.J., F.R.S., in Br. Jour. of Photography._
* * * * *
ELECTRICITY AS A PREVENTIVE OF SCALE IN BOILERS.
The mineral sediment that generally sticks to the sides of steam boilers,
and the presence of which is fraught with the utmost danger, resulting in
many instances in great injury to life and property, besides eating away
the substance of the iron plate, was referred to in a paper lately read by
M. Jeannolle before the Paris Academy of Sciences, in which the author
described a new method for keeping boilers clean. This method is as
follows:
The inside of a steam boiler is placed, by means of piles of a certain
power, in reciprocal communication, the current passing at one end through
positive, and at the other through negative, wires. In incrusted steam
boilers, at a temperature ranging from 212° to 300° Fahr., and a pressure
of from 30 to 90 lb. to the square inch, the current thus engendered
decomposes the accumulated salts, and precipitates them, from which they
may easily be removed, either by means of a special siphon or by means of
some other mechanical process. When boilers are free from fur, and where
it is intended to keep them free from such, a continuous current may be
set up, by means of which the sedimentary salts may be decomposed, and a
precipitate produced in a pulverized form, which can be removed with equal
facility.
From a series of minute experiments made by M. Jeannolle, it appears that
in order to render the various actions of electricity, perfect, it is
necessary to coat either with red lead or with pulverized iron, or with
any other conductor of electricity, an operation which must be repeated
whenever the boiler is emptied with a view to cleaning out. The above
system Is being advantageously applied in Calais for removing the
incrustations of boilers. The two poles of a battery of ten to twelve
Bunsen elements are applied to the ends of the boilers, and after thirty
to forty hours the deposits fall from the sides to the bottom. When a
boiler has been thus cleared, the formation of new deposits may be
prevented by applying a much less energetic current under the same
conditions.
* * * * *
ALPHABET DESIGNED BY GODFREY SYKES.
[Illustration: SUGGESTIONS IN DECORATIVE ART.--ALPHABET DESIGNED BY
GODFREY SYKES.]
Among the many designs which have been issued by the South Kensington
Museum authorities is the alphabet which we have illustrated here to-day.
The letters appear frequently among the decorations of the museum
buildings, especially in the refreshment rooms and the Ceramic gallery,
where long inscriptions in glazed terra cotta form ornamental friezes. The
alphabet has also been engraved to several sizes, and is used for the
initial letters in the various official books and art publications
relating to the museum, which are published by the Science and Art
Department.--_Building News._
* * * * *
OLD WROUGHT IRON GATE.
[Illustration: OLD WROUGHT IRON GATE]
This gate forms the entrance to Scraptoft Hall, a building of the
eighteenth century, now the seat of Captain Barclay, and which stands at
about five miles from Leicester, England.--_The Architect._
* * * * *
BRIEF SANITARY MATTERS IN CONNECTION WITH ISOLATED COUNTRY HOUSES.[4]
[Footnote 4: Read before the Boston Society of Civil Engineers, April 1884
_Journal A. of E. Societies_.]
By E.W. BOWDITCH, C.E.
I am unable to tell you what is generally considered the best practice,
for I am not sure there are any definitely established rules; therefore I
can only explain _my_ ways of doing such work, which, though I try to make
as complete and at the same time as simple as possible, I know to be far
from perfect.
Plumbing and drainage work has grown up unconsciously with my landscape
gardening, and not finding any texts or practice that seemed wholly
satisfactory, I have been forced to devise new arrangements from time to
time, according to the requirements of the case in hand.
To give all the details of house plumbing this evening, or any _one_
evening, would be impossible, for lack of time, and not worth while even
if there was time, as much of it would prove matter of little or no
interest. I will confine my remarks, therefore, to certain elements of the
work where my practice differs, I believe, essentially from that of most
engineers, and where perhaps my experience, if of no assistance to other
members of the Society, may excite their friendly criticism in such a way
as to help me.
There are two kinds of country places that I am liable to be called upon
to prescribe for:
_First._ A new place where nothing has been arranged.
_Second._ An old place where the occupants have been troubled either by
their outside arrangements or by fixtures or pipes within.
Under the first head let us suppose a small tract of perhaps two acres of
land in some inland town, where the family intends to live but six months
in the year, though they are liable to reside there the whole twelve.
There are no sewers and no public water. The soil is a stiff, retentive
clay, rather wet in spring. The desire is expressed to have plumbing and
drainage that shall be as inexpensive as possible, but that shall be
entirely safe.
In considering the arrangements inside the house, I find myself in the
same predicament as the French surgeon, a specialist upon setting the
bones of the arm, who, when a patient was brought him with his right arm
broke, expressed his sorrow at being unable to be of assistance, as his
specialty was the left arm.
I have endeavored to post myself thoroughly upon house plumbing, but
confess to only knowing partially about the wastes; the supplies I do not
feel competent to pass upon.
One class of annoyance caused by plumbing, perhaps the principal one, is
due to the soil pipe or some of its fittings.
Second quality of iron, poor hanging, insufficient calking, careless
mechanics, putty, cement, rag, or paper joints--all these and a dozen
other things are liable to be sources of trouble. Subordinate wastes are
apt to be annoying, occasionally, too, to a less extent.
The mechanical work can always be superintended, and within certain limits
may be made secure and tight; not so easy, however, with the materials.
There is seldom a valid excuse for ever making waste pipes, within a
building, of anything but metal.
Earthen tile is frequently used; also, to a limited extent, brick, stone,
and wood; twice I have found canvas--all these, however, are inferior, and
should never be accepted or specified. The writer believes that at the
present time, hereabouts, lead and iron are more used for wastes than any
other materials, and are found the most satisfactory on the whole.
One or two arrangements, relative to the wastes, I have made use of that
are not, so far as known, in general use, and that may not be the best,
though they have served me many good turns, and I have not succeeded in
devising any better.
Soil pipe, as it is usually put in, is apt to be of cast iron, four inches
in diameter, and is known in the market as "heavy" or "extra heavy." For
some years the tar-coated or black enameled pipe has been the favorite, as
being the more reliable, the writer in common with others making use of
the same freely, until one day a cracked elbow, tar coated, was detected.
Since that time plain, untarred pipe has been specified, and subjected to
the so-called kerosene test, which consists of swabbing out each pipe with
kerosene or oil and then allowing it to stand for a few hours. A moment's
thought will convince any one that when a pipe is asphalted or tar coated
it is very difficult to detect either sand holes or small cracks, and the
difficulty of proper calking is increased, as lead does not cling so well
to the tar as to plain iron.
At present, the kerosene test, so far as the writer is concerned, is a
misnomer, because raw linseed oil is used exclusively as giving more
satisfactory results, and being less troublesome to apply.
I have here a length of the ordinary "heavy 4" commercial soil pipe,
plain, and selected at random. Yesterday noon I had it oiled at my office,
in order to be ready for to-night, and you see, by the chalk marks I have
made, just where the leaks were and their area. I may say here that a
sound pipe of this caliber and standard weight is the exception rather
than the rule, and it was selected for this experiment merely to try and
show the reaction a little better than the heavier pipe might.
Experiments of this nature I have carried along for the past two years,
and I am glad to say that, since I began, the quality of the soil pipe
furnished by the dealers for my work seems appreciably better than at
first. Whether the poorer pipe is still made and sold to other customers I
have no means of knowing; probably it is, however.
A large quantity of the pipe is now being tested at my suggestion by the
Superintendent of Construction of the Johns Hopkins Hospital, at
Baltimore. I have not yet heard the results from him, but doubtless they
will be interesting. A brief summary of the results may be of some
interest.
The different makers of soil pipe generally used by plumbers hereabouts
are:
Mott & Company, Abendroth, Blakslee, Dighton, Phillips & Weeden, and
Bartlett, Hayward & Co.
On 4" extra heavy pipe my results have been as follows:
Percentage passed as good, single hub. 60 per ct. to 70 per ct.
Percentage passed as good, double. 20 per ct. to 80 per ct.
Percentage passed special castings,
including Y's and T's. 60 per ct.
5" pipe extra heavy:
Percentage passed as good, single hub. 25 per ct. to 35 per ct.
Percentage passed as good, double. No record.
Percentage special castings,
including Y's and T's. 60 per ct.
It has been stated to me by dealers that the tar coating does away with
the necessity of any such test as the oil; while I am not prepared to
acknowledge or deny the statement, it is well known that much poor pipe is
tar-coated and sold in the market as good, and when coated it is almost
impossible to detect any but _very_ defective work.
The price customers are obliged to pay for soil pipe, either "heavy" or
"extra heavy," is very high indeed, even taking off the discounts, and
amounts (as I figure it) to $70 per long ton for 4" pipe. The present rate
for the best water pipe of the same caliber is about $38 (now $29) per
long ton, and the additional charge for soil pipe should guarantee the
very best iron in the market, though it appears to be rarely furnished.
It is asserted that all soil pipe is tested to a 50-pound water pressure.
I beg leave to question the absolute truth of this, unless it be
acknowledged that pipe is sold indiscriminately, whether it bears the test
or not, for more than once I have found a single length of soil pipe (5
feet) that could not bear the pressure of a column of water of its own
height without leaking.
Having obtained a satisfactory lot of soil pipe and fittings, the next
trouble comes with the lead calking. Unfortunately, it is frequently found
that very shallow joints are made instead of deep ones, and hard lead used
instead of soft. My rule is, soft lead, two runnings and two calkings. By
soft lead I mean pig lead, and by hard lead I mean old pipe and scrap lead
that may have been melted a dozen times. Incidentally it may be remarked
that it is quite difficult to calk a tight joint on the heavy pipe; the
process will crack the hub.
The fixtures used in a house are of minor importance--there are dozens of
good patterns of every class. If they are carefully put in, and provided
with suitable traps placed just as close to the fixture as possible, the
result will usually be satisfactory.
Very few instances occur where traps are placed as close to the fixtures
they serve as they might be, and yet a very short length of untrapped
pipe, when fouled, will sometimes smell dreadfully. A set bowl with trap
two feet away may become in time a great nuisance if not properly used. A
case in point where the fixture was used both as a bowl and a urinal was
in a few months exceedingly offensive--a fact largely (though not wholly)
due to its double service.
I have never met two sanitarians who agreed upon the same water-closets,
bowls, faucets, traps, etc.
Of course, the soil pipe will be carried, of full size, through the roof,
and sufficiently high to clear all windows.
Avoid multiplicity of fixtures or pipes; cut off all fixtures not used at
least twice a week, lest their traps dry out; have all plumbing as simple
as possible, and try and get it all located so that outside air can be got
directly into all closets and bath-rooms. As far as possible, set your
fixtures in glass rather than tiles or wood. Carry the lower end of the
main drain at least five feet beyond the cellar walls of the building, of
cast iron.
Let us now look at the outside work. The main drain (carrying everything
except the kitchen and pantry sinks) goes through a ventilated running
trap. An indirect fresh air inlet is provided on the house side of the
trap (example), to prevent annoyance from puffing or pumping, or, better
still, a pipe corresponding to the soil pipe is carried up on the outside
of the house.
The running trap ventilator should be of the same diameter as the main
drain (4 inch), and serve as a main drain vent also. Carry this pipe on
the outside of the house as high as the top of the chimney.
A grease-trap should be provided for the kitchen and pantry sinks.
Formerly my custom was to put in brick receptacles; it is now to put in
Portland cement traps (Henderson pattern), though perhaps I may succeed in
devising a cast-iron one that will answer better. The brick ones were
occasionally heaved by the frost, and cracked; the Portland cement ones
answer better, and when thoroughly painted with red lead do not soak an
appreciable quantity of sewage to be offensive, but are too high priced
($28 each). I have made one or two patterns for cast-iron ones, but none
as yet that I feel satisfied with.
Beyond the running trap an Akron pipe should convey the sewage to a tank
or cesspool.
Our supposable case is the second most difficult to take care of. The
worst would be ledge. We have to contend with, however, hard, wet,
impervious clay.
The best way undoubtedly is to underdrain the land, and then to distribute
the sewage on the principle of intermittent downward filtration. This is
rather expensive, and a customer is rarely willing to pay the bills for
the same. I should always advise it as the best; but where not allowed to
do so, I have had fair success with shallow French drains connecting with
the tank or cesspool.
Siphon tanks, such as are advised by many sanitarians, that were used
first in this country, I believe, by Mr. Waring, I have not been very
successful with. Obstructions get into the siphon and stop it up, or it
gets choked with grease. I prefer a tight tank, provided with a tell-tale,
and that is to be opened either by a valve operated by hand, or that is
arranged with a standing overflow like a bath tub, and that can be raised
and secured by a hook.
* * * * *
SANITARY COOKING.[5]
[Footnote 5: Read before the Indiana State Sanitary Society, Seymour,
March 13, 1884.--_The Sanitarian._]
By VIRGINIA L. OPPENHEIMER, M.D., Seymour, Ind.
"We may live without poetry, music, and art,
We may live without conscience, and live without heart,
We may live without friends,
We may live without books,
But civilized man cannot live without cooks.
"We may live without books--
What is knowledge but grieving?
We may live without hope--
What is hope but deceiving?
We may live without love--what is passion but pining?
But where is the man that can live without dining?"
Thus saith the poet, and forthwith turns the world over into the hands of
the cook. And into what better hands could you fall? To you, my fat,
jolly, four-meals-a-day friend, Mr. Gourmand, but more especially to
_you_, my somber, lean, dyspeptic, two-meals-a-day friend, Mr. Grumbler,
the cook is indeed a valuable friend. The cook wields a scepter that is
only second in power to that of love; and even love has become soured
through the evil instrumentality of the good-looking or bad-cooking cook.
This is no jest, it is a very sad fact.
Now, the question arises, how can the cook preserve the health of her
patrons, maintain happiness in the family, and yet not throw the gourmands
into bankruptcy? Very simple, I assure you.
1. You must have _the_ cook. I mean by this, that not every one can occupy
that important office. The greatest consideration in the qualities of a
cook is, does she like the work? No one can fulfill the duties of any
noteworthy office unless he labors at them with vim and willingness.
2. You must have good articles of food originally.
3. As our honest Iago said, "You must have change."
When one arrives at adult age, he should have learned by experience what
articles of food _do_, and what articles of food do _not_, agree with him,
and to shun the latter, no matter how daintily served or how tempting the
circumstances. The man who knows that _pates de foie gras_, or the livers
of abnormally fattened geese, disagree with him, and still eats them, is
not to be pitied when all the horrors of dyspepsia overtake him.
The cooking of any article of food has evidently much, very much, to do
with its digestibility. It is not the purpose of this paper to teach
cooking, but merely to give some general hints as to the best as well as
the simplest methods of preparing staple articles of food. The same
articles of food can and should be prepared differently on each day of the
week. Changes of diet are too likely to be underestimated. By constant
change the digestive organs in the average person are prevented from
having that repulsion of food which, to a greater or less extent, is
likely to result from a sameness of diet continued for a long time.
We often hear from our scientific men that this or that article of food is
excellent for muscle, another for brain, another for bone, etc., etc. Now,
stubborn facts are like stone walls, against which theories often butt out
their beauty and their power. It is well known to almost every one
nowadays that _well-cooked_ food, whether it be potatoes, meat and bread,
fish, or anything else worthy the name of food, will well maintain,
indefinitely, either the philosopher or the hodcarrier.
Many of you know, and all of you ought to know, that the principal
ingredients of nearly all our foods are starch and albumen. Starch is the
principal nutritive ingredient of vegetables and breadstuffs. Albumen is
the principal ingredient of meats, eggs, milk, and other animal
derivatives.
Starch never enters the system as starch, but must first be converted into
sugar either in the body or out of it. The process of this transformation
of starch into sugar is beautifully exemplified in certain plants, such as
the beet, the so-called sugar cane, and other growths. The young plant is,
to a great extent, composed of starch; as the plant grows older, a
substance is produced which is called _diastase_. Through the influence of
this _diastase_ the starch is converted into a peculiar non-crystallizable
substance called _dextrine_, and as the plant matures, this dextrine is
transformed into crystallizable sugar.
"Dextrine is a substance that can be produced from starch by the action of
dilute acids, alkalies, and malt extract, and by roasting it at a
temperature between 284° and 330° F., till it is of a light brown color,
and has the odor of overbaked bread."
A simple form of dextrine may be found in the brown crust of bread--that
sweetish substance that gives the crust its agreeable flavor. Pure
dextrine is an insipid, odorless, yellowish-white, translucent substance,
which dissolves in water almost as readily as sugar. As stated above, it
is easily converted into _dextrose_, or _glucose_, as it is usually named.
This _glucose_ is often sold under the name of sugar, and is the same
against which so many of the newspapers waged such a war a year or two
ago. These critics were evidently, for the most part, persons who knew
little about the subject. Glucose, if free from sulphuric acid or other
chemicals, is as harmless as any other form of sugar. Most of our candies
contain more or less of it, and are in every way as satisfactory as when
manufactured wholly from other sugars.
It is, therefore, self-evident that, as sugar is a necessary article of
food, the process which aids the transformation of our starchy foods must
necessarily aid digestion. Do not understand me to say by this that, if
all our starchy foods were converted into sugar, their digestion would
thereby be completed. As I stated a moment ago, this sweet food, if taken
into the stomach day after day, would soon cause that particular organ to
rebel against this sameness of diet. In order the more clearly to
illustrate this point, I will briefly show you how some of the every-day
articles of food can be each day differently prepared, and thus be
rendered more palatable, and, as a consequence, more digestible; for it is
a demonstrated fact that savory foods are far more easily digested than
the same foods unsavored.
The art of serving and arranging dishes for the table is an accomplishment
in itself. It is very reasonable that all things that go to make up beauty
and harmony at the dinner table should add their full quota to the
appetite, and, I was about to say, "to the digestion;" but will qualify
the statement by saying, to the digestion if the appetite be not porcine.
Our commonest article of food is the _potato_. Let us see how
potatoes--which contain only twenty per cent. of starch, as against
eighty-eight per cent. in rice, and sixty-six per cent. in wheat
flour--can be prepared as just mentioned. We will look for a moment at the
manner in which they are usually served by the average cook:
1, boiled with their jackets on; 2, roasted in the embers; 3, roasted with
meat; 4, fried; 5, mashed; 6, salad.
1. Potatoes boiled in their jackets are excellent if properly prepared.
But there's the rub. The trouble is, they are too often allowed to boil
slowly and too long, and thus become water-soaked, soggy, and solid, and
proportionately indigestible. They should be put over a brisk fire, and
kept at a brisk boil till done; then drain off the water, sprinkle a
little salt over them, and return to the fire a moment to dry thoroughly,
when you will find them bursting with their white, mealy contents.
2. Roasted potatoes are general favorites, and very digestible. A more
agreeable flavor is imparted to them if roasted in hot embers (wood fire),
care being used to keep them covered with the hot embers.
3. Fried potatoes, as they are very generally served, are almost as
digestible as rocks, but not so tempting in all their grease-dripping
beauty as the latter. Many of you have doubtless seen the potatoes neatly
sliced and dumped into a frying pan full of hot lard, where they were
permitted to sink or float, and soak and sob for about a half hour or
more. When served, they presented the picturesque spectacle of miniature
potato islands floating at liberty in a sea of yellow grease. Now, if any
of you can relish and digest such a mess as that, I would advise you to
leave this clime, and eat tallow candles with the Esquimaux.
If you are fond of fried potatoes, cook them in this way:
Take what boiled potatoes are left from breakfast or dinner; when cold,
remove the jackets, and cut into thin slices, season with salt, pepper,
and a little Cayenne; have ready a hot frying pan, with enough meat
drippings or sweet lard to cover the bottom; put in the potatoes and fry a
rich brown, stirring constantly with a knife to prevent burning. Serve
very hot.
4. Mashed potatoes will be discussed further on.
5. Potato salads are appetizing and piquant, because they are usually made
up with strong condiments, onions, etc. They are, therefore, not very
digestible in themselves. Nevertheless, they are so palatable that we
cannot easily dispense with them; but, after eating them, if you expect to
have inward peace, either split wood, walk eight and a half miles, or take
some other light exercise.
More palatable, and proportionately digestible, are the following methods
of cooking this useful vegetable:
1, Saratoga potatoes; 2, a la maitre d'hotel; 3, potato croquettes; 4,
potatoes and cream; 5, a la Lyonnaise.
1. For _Saratogas_, pare and slice your potatoes as thin as possible,
dropping them into cold water in which is dissolved a tiny piece of alum
to make them crisp. Let them remain in the water for an hour or longer.
Drain, and wipe perfectly dry with a tea towel. Have ready a quantity of
boiling lard. Drop them in, and fry a delicate brown. Drain all grease
from them, sprinkle with salt, and serve. Here, in the crisp slices, you
will have the much desired dextrine. Or, in other words, your potato is
already half digested. Eat three or four potatoes prepared thus, and you
feel no inconvenience; but how would you feel did you devour three soggy,
water-soaked _boiled_ potatoes?
2. For _a la maitre d'hotel_, pare the potatoes, cut into pieces half an
inch wide, and the length of the potato; drop into cold water until wanted
(an hour or so); then drain, and fry in boiling lard. Just as they begin
to brown take them out with a skimmer; let them slightly cool; then put
back, and fry a rich brown. This makes them puff up, and very attractive.
3. For _croquettes_, take finely mashed potatoes, and mix with salt,
pepper, and butter, and sweet milk or cream enough to moisten thoroughly.
Mix with this one well-beaten egg, and form into small balls, taking care
to have them smooth. Have ready one plate with a beaten egg upon it, and
another with cracker crumbs. Dip each ball into the egg, and then into the
crumbs, and brown nicely. Lay the croquettes on brown paper first, to get
rid of any superfluous grease, then serve on a napkin.
4. _Potatoes and cream_ are prepared by mincing cold boiled potatoes fine,
putting them in a spider with a little melted butter in it, and letting
them fry slightly, keeping them well covered. Add a very small piece of
fresh butter, season with pepper and salt, and pour over them cream or
rich milk. Let them boil up once, and serve. This is a very nice dish, and
may be safely taken into delicate stomachs.
5. _A la Lyonnaise_ is prepared as follows: Take five cold potatoes, one
onion, butter, salt, and pepper. Slice the onion finely, and fry it in
butter until it begins to take color; add the sliced potatoes, salt and
pepper to taste, and keep shaking the saucepan until they are somewhat
browned. Serve hot.
A few random remarks about the preparation of albuminous foods. If the
albumen in food is hardened by prolonged cooking, it is rendered _less_
instead of more digestible. Therefore, the so-called _well-cooked_ meats
are really _badly-cooked_ meats. Meats should be only half done, or rare.
To do this properly, it is necessary to cook with a quick fire. Steaks
should be broiled, not fried. I am in accord with a well-known orator, who
said, recently, that "the person who fries a steak should be arrested for
cruelty to humanity." Some few meats should always be well cooked before
eating.[6]
[Footnote 6: These are the exceptions. Pork, on account of the prevalence
of disease in hogs, should be well done.]
The same law holds good with eggs as with meats. A hard-boiled egg is only
fit for the stomach of an ostrich; it was never intended by nature to
adorn the human stomach. There are very many ways of preparing eggs--by
frying, baking, poaching, shirring, etc. I will only describe briefly a
few simple methods of making omelets.
In making this elegant dish, never use more than three eggs to an
_omelet_. Plain omelet: Separate the whites and yolks; add a teaspoonful
of water to the whites, and beat to a stiff froth; add to the yolks a
teaspoonful of water, and beat until light; then season with salt, and
about two tablespoonfuls of cream or rich milk. Have your spider very hot;
turn your whites and yolks together, and stir lightly to mix them; place a
bit of butter in the spider, and immediately pour in your eggs. When set
(which takes from ten to twenty seconds, and be careful that it does not
brown too much), fold together in a half moon, remove it, sprinkle with
powdered sugar, and serve on a hot plate. It should be eaten immediately.
Fruit omelets are made by placing preserved fruits or jellies between the
folds. Baked omelets are prepared as above, with the addition of placing
in the oven and allowing to brown slightly.
French omelet is prepared in this way: Take a half cup of boiling milk
with a half teaspoonful of butter melted in it; pour this over one-half
cup of bread crumbs (light bread); add salt, pepper, and the yolks of
three eggs beaten very light; mix thoroughly; and lastly, add the whites
whipped to a stiff froth. Stir lightly, and fry in butter. When nearly
done, fold together in a half moon, and serve immediately.
And thus we might continue _ad infinitum_, but, as was stated before, it
is not my object to instruct you in special cooking, but to illustrate in
this manner how much easier it is, to both the cook and your stomachs, to
prepare healthful dishes than to do the reverse.
* * * * *
TIME REQUIRED TO DIGEST DIFFERENT FOODS.
_The Monitor de la Salud_ contains in a recent number the results of some
experiments lately made by E. Jessen on the time required for the
digestion of certain kinds of food. The stomach of the person on whom the
experiments were made was emptied by means of a pump; 100 grammes, equal
to 1,544 grains, or about 2-2/3 ounces, of meat, finely chopped and mixed
with three times the quantity of water, were introduced. The experiment
was considered ended when the matter, on removal by the pump, was found to
contain no muscular fibre.
It will be remembered that the gramme weighs nearly 15-1/2 grains, and the
cubic centigramme is equal to 1 gramme. The 2-2/3 ounces of meat were
therefore mixed with nearly eight ounces of water, before being introduced
into the stomach.
The results were as follows:
Beef, raw, and finely chopped. 2 hours.
" half cooked. 2½ "
" well cooked. 3 "
" slightly roasted. 3 "
" well roasted. 4 "
Mutton, raw. 2 "
Veal. 2½ "
Pork. 3 "
The digestibility of milk was examined in the same way. The quantity used
was regulated so that the nitrogen should be the same as in the 100
grammes of beef.
602 cubic centimeters, nearly sixteen ounces,
of cow's milk, not boiled, required. 3½ hours
602 cubic centimeters, boiled. 4 "
602 " " sour. 3½ "
675 " " skimmed. 3½ "
656 " " goat's milk, not boiled. 3½ "
* * * * *
THE ORGANIZATION AND PLAN OF THE UNITED STATES GEOLOGICAL SURVEY.[7]
[Footnote 7: Communicated to the National Academy of Sciences at the
October meeting in 1884.]
By J.W. POWELL.
A Scientific institution or bureau operating under government authority
can be controlled by statute and by superior administrative authority but
to a limited extent. These operations are practically carried on by
specialists, and they can be controlled only in their financial operations
and in the general purposes for which investigations are made. Their
methods of investigation are their own--originate with themselves, and are
carried out by themselves. But in relation to the scientific operations of
such a government institution, there is an unofficial authority which,
though not immediately felt, ultimately steps in to approve or condemn,
viz., the body of scientific men of the country; and though their
authority is not exercised antecedently and at every stage of the work,
yet it is so potent that no national scientific institution can grow and
prosper without their approval, but must sooner or later fall and perish
unless sustained by their strong influence.
As director of the Geological Survey, I deeply realize that I owe
allegiance to the scientific men of the country, and for this reason I
desire to present to the National Academy of Sciences the organization and
plan of operations of the Survey.
A TOPOGRAPHIC MAP OF THE UNITED STATUS.
Sound geologic research is based on geography. Without a good topographic
map geology cannot even be thoroughly studied, and the publication of the
results of geologic investigation is very imperfect without a good map;
but with a good map thorough investigation and simple, intelligible
publication become possible. Impelled by these considerations, the Survey
is making a topographic map of the United States. The geographic basis of
this map is a trigonometric survey by which datum points are established
throughout the country; that is, base-lines are measured and a
triangulation extended therefrom. This trigonometric work is executed on a
scale only sufficiently refined for map-making purposes, and will not be
directly useful for geodetic purposes in determining the figure of the
earth. The hypsometric work is based upon the railroad levels of the
country. Throughout the greater part of the country, there is a system of
railroad lines, constituting a net-work. The levels or profiles of these
roads have been established with reasonable accuracy, and as they cross
each other at a multiplicity of points, a system of checks is afforded, so
that the railroad surface of the country can be determined therefrom with
all the accuracy necessary for the most refined and elaborate topographic
maps. From such a hypsometric basis the reliefs for the whole country are
determined, by running lines of levels, by trigonometric construction, and
in mountainous regions by barometric observation.
The primary triangulation having been made, the topography is executed by
a variety of methods, adapted to the peculiar conditions found in various
portions of the country. To a large extent the plane-table is used. In the
hands of the topographers of the Geological Survey, the plane-table is not
simply a portable draughting table for the field; it is practically an
instrument of triangulation, and all minor positions of the details of
topography are determined through its use by trigonometric construction.
The scale on which the map is made is variable. In some portions of the
prairie region, and in the region of the great plains, the topography and
the geology alike are simple, and maps on a comparatively small scale are
sufficient for practical purposes. For these districts it is proposed to
construct the sheets of the map on a scale of 1-250,000, or about four
miles to the inch. In the mountain regions of the West the geology is more
complex, and the topography more intricate; but to a large extent these
regions are uninhabited, and to a more limited extent uninhabitable. It
would therefore not be wise to make a topographic or geologic survey of
the country on an excessively elaborate plan. Over much of this area the
sheets of the map will also be constructed on a scale of 1-250,000, but in
special districts that scale will be increased to 1-125,000, and in the
case of important mining districts charts will be constructed on a much
larger scale. In the eastern portion of the United States two scales are
adopted. In the less densely populated country a scale of 1-125,000 is
used; in the more densely populated regions a scale of 1-62,500 is
adopted, or about one mile to the inch. But throughout the country a few
special districts of great importance, because of complex geologic
structure, dense population, or other condition, will require charts on
still larger scales. The area of the United States, exclusive of Alaska,
is about three million square miles, and a map of the United States,
constructed on the plan set forth above, will require not less than 2,600
sheets. It may ultimately prove to require more than that, from the fact
that the areas to be surveyed on the larger scale have not been fully
determined. Besides the number of sheets in the general map of the United
States, there will be several hundred special maps on large scales, as
above described.
Such is a brief outline of the plan so far as it has been developed at the
present time. In this connection it should be stated that the map of the
United States can be completed, with the present organization of the
Geological Survey, in about 24 years; but it is greatly to be desired that
the time for its completion may be materially diminished by increasing the
topographic force of the Geological Survey. We ought to have a good
topographic map of the United States by the year 1900. About one-fifth of
the whole area of the United States, exclusive of Alaska, has been
completed on the above plan. This includes all geographic work done in the
United States under the auspices of the General Government and under the
auspices of State Governments. The map herewith shows those areas that
have been surveyed by various organizations on such a scale and in such a
manner that the work has been accepted as sufficient for the purposes of
the Survey.
Much other work has been done, but not with sufficient refinement and
accuracy to be of present value, though such work subserved its purpose in
its time. An examination of the map will show that the triangulation of
the various organizations is already largely in advance of the topography.
The map of the United States will be a great atlas divided into sheets as
above indicated. In all of those areas where the survey is on a scale of
1-250,000, a page of the atlas will present an area of one degree in
longitude and one degree in latitude. Where the scale is 1-125,000, a page
of the atlas-sheet will represent one-fourth of a degree. Where the scale
is 1-62,500, the atlas-sheet will represent one-sixteenth of a degree. The
degree sheet will be designated by two numbers--one representing latitude,
the other longitude. Where the sheets represent fractional degrees, they
will be labeled with the same numbers, with the addition of the
description of the proper fractional part.
The organization, as at present established, executing this work, is as
follows: First, an astronomic and computing division, the officers of
which are engaged in determining the geographic coordinates of certain
primary points. Second, a triangulation corps engaged in extending a
system of triangulation over various portions of the country from measured
base-lines. Third, a topographic corps, organized into twenty-seven
parties, scattered over various portions of the United States. Such, in
brief outline, is the plan for the map of the United States, and the
organization by which it is to be made. Mr. Henry Gannett is the Chief
Geographer.
PALEONTOLOGY.
Before giving the outline of the plan for the general geologic survey, it
will be better to explain the accessory plans and organizations. There are
in the Survey, as at present organized, the following paleontologic
laboratories:
1. A laboratory of vertebrate paleontology for formations other than the
Quaternary. In connection with this laboratory there is a corps of
paleontologists. Professor O.C. Marsh is in charge.
2. There is a laboratory of invertebrate paleontology of Quaternary age,
with a corps of paleontologists, Mr. Wm. H. Dall being in charge.
3. There is a laboratory of invertebrate paleontology of Cenozoic and
Mesozoic age, with a corps of paleontologists. Dr. C.A. White is in
charge.
4. There is a laboratory of invertebrate paleontology of Paleozoic age,
with a corps of paleontologists. Mr. C.D. Walcott is in charge.
5. There is a laboratory of fossil botany, with a corps of paleobotanists,
Mr. Lester F. Ward being in charge.
The paleontologists and paleobotanists connected with the laboratories
above described, study and discuss in reports the fossils collected by the
general geologists in the field. They also supplement the work of the
field geologists by making special collections in important districts and
at critical horizons; but the paleontologists are not held responsible for
areal and structural geology on the one hand, and the geologists are not
held responsible for paleontology on the other hand. In addition to the
large number of paleontologists on the regular work of the Geological
Survey, as above described, several paleontologists are engaged from time
to time to make special studies.
CHEMISTRY.
There is a chemic laboratory attached to the Survey, with a large corps of
chemists engaged in a great variety of researches relating to the
constitution of waters, minerals, ores, and rocks. A part of the work of
this corps is to study the methods of metamorphism and the paragenesis of
minerals, and in this connection the chemists do work in the field; but to
a large extent they are occupied with the study of the materials collected
by the field geologists. Professor F.W. Clarke is in charge of this
department.
PHYSICAL RESEARCHES.
There is a physical laboratory in the Survey, with a small corps of men
engaged in certain physical researches of prime importance to geologic
philosophy. These researches are experimental, and relate to the effect of
temperatures, pressures, etc., on rocks. This laboratory is under the
charge of the chief chemist.
LITHOLOGY.
There is a lithologic laboratory in the Survey, with a large corps of
lithologists engaged in the microscopic study of rocks. These lithologists
are field geologists, who examine the collections made by themselves.
STATISTICS.
There is in the Survey a division of mining statistics, with a large corps
of men engaged in statistic work, the results of which are published in an
annual report entitled "Mineral Resources." Mr. Albert Williams, Jr., is
the Chief Statistician of the Survey.
ILLUSTRATIONS.
There is in the Survey a division organized for the purpose of preparing
illustrations for paleontologic and geologic reports. Mr. W.H. Holmes is
in charge of this division. Illustrations will not hereafter be used for
embellishment, but will be strictly confined to the illustration of the
text and the presentation of such facts as can be best exhibited by
figures and diagrams. All illustrations will, as far as possible, be
produced by relief methods, such as wood-engraving, photo-engraving, etc.
As large numbers of the reports of the Survey are published, this plan is
demanded for economic reasons; but there is another consideration believed
to be of still greater importance; illustrations made on stone cannot be
used after the first edition, as they deteriorate somewhat by time, and it
is customary to use the same lithographic stone for various purposes from
time to time. The illustrations made for the reports of the Survey, if on
relief-plates that can be cheaply electrotyped, can be used again when
needed. This is especially desirable in paleontology, where previously
published figures can be introduced for comparative purposes. There are
two methods of studying the extinct life of the globe. Fossils are indices
of geological formations, and must be grouped by formations to subserve
the purpose of geologists. Fossils also have their biologic relations, and
should be studied and arranged in biologic groups. Under the plan adopted
by the Survey, the illustrations can be used over and over again for such
purposes when needed, as reproduction can be made at the small cost of
electrotyping. These same illustrations can be used by the public at large
in scientific periodicals, text-books, etc. All the illustrations made by
the Geological Survey are held for the public to be used in this manner.
LIBRARY.
The library of the Survey now contains more than 25,000 volumes, and is
rapidly growing by means of exchanges. It is found necessary to purchase
but few books. The librarian, Mr. C.C. Darwin, has a corps of assistants
engaged in bibliographic work. It is proposed to prepare a catalogue of
American and foreign publications upon American geology, which is to be a
general authors' catalogue. In addition to this, it is proposed to publish
bibliographies proper of special subjects constituting integral parts of
the science of geology.
PUBLICATIONS.
The publications of the Survey are in three series: Annual Reports,
Bulletins, and Monographs. The Annual Report constitutes a part of the
Report of the Secretary of the Interior for each year, but is a distinct
volume. This contains a brief summary of the purposes, plans, and
operations of the Survey, prepared by the Director, and short
administrative reports from the chiefs of divisions, the whole followed by
scientific papers. These papers are selected as being those of most
general interest, the object being to make the Annual Report a somewhat
popular account of the doings of the Survey, that it may be widely read by
the intelligent people of the country. Of this 5,650 copies are published
as a part of the Secretary's report, and are distributed by the Secretary
of the Interior, Senators, and Members of the House of Representatives;
and an extra edition is annually ordered of 15,000 copies, distributed by
the Survey and members of the Senate and House of Representatives. Four
annual reports have been published; the fifth is now in the hands of the
printer.
The Bulletins of the Survey are short papers, and through them somewhat
speedy publication is attained. Each bulletin is devoted to some specific
topic, in order that the material ultimately published in the bulletins
can be classified in any manner desired by scientific men. Nine bulletins
have been published, and seven are in press. The bulletins already
published vary in size from 5 to 325 pages each; they are sold at the cost
of press-work and paper, and vary in price from five to twenty cents each;
4,900 copies of each bulletin are published; 1,900 are distributed by
Congress, 3,000 are held for sale and exchange by the Geological Survey.
The Monographs of the Survey are quarto volumes. By this method of
publication the more important and elaborate papers are given to the
public. Six monographs, with two atlases, have been issued; five
monographs, with two atlases, are in press; 1,900 copies of each monograph
are distributed by Congress; 3,000 are held for sale and exchange by the
Survey at the cost of press-work, paper, and binding. They vary in price
from $1.05 to $11.
The chiefs of divisions supervise the publications that originate in their
several corps. The general editorial supervision is exercised by the Chief
Clerk of the Survey, Mr. James C. Pilling.
GENERAL GEOLOGY.
In organizing the general geologic work, it became necessary, first, to
consider what had already been done in various portions of the United
States; and for this purpose the compilation of a general geologic map of
the United States was begun, together with a Thesaurus of American
formations. In addition to this the bibliographic work previously
described was initiated, so that the literature relating to American
geology should be readily accessible to the workers in the Survey. At this
point it became necessary to consider the best methods of apportioning the
work; that is, the best methods of dividing the geologic work into parts
to be assigned to the different corps of observers. A strictly geographic
apportionment was not deemed wise, from the fact that an unscientific
division of labor would result, and the same classes of problems would to
a large extent be relegated to the several corps operating in field and in
the laboratory. It was thought best to divide the work, as far as
possible, by subject-matter rather than by territorial areas; yet to some
extent the two methods of division will coincide. There are in the Survey
at present:
First, a division of glacial geology, and Prof. T.C. Chamberlin, formerly
State Geologist of Wisconsin is at its head, with a strong corps of
assistants. There is an important field for which definite provision has
not yet been made, namely, the study of the loess that constitutes the
bluff formations of the Mississippi River and its tributaries. But as this
loess proves to be intimately associated with the glacial formations of
the same region, it is probable that it will eventually be relegated to
the glacial division. Perhaps the division may eventually grow to such an
extent that its field of operations will include the whole Quaternary
geology.
Second, a division of volcanic geology is organized, and Capt. Clarence E.
Dutton, of the Ordnance Corps of the Army, is placed in charge, also with
a strong corps of assistants.
Third and fourth, two divisions have been organized to prosecute work on
the archæan rocks, embracing within their field not only all rocks of
archæan age, but all metamorphic crystalline schists, of whatever age they
may be found. The first division has for its chief Prof. Raphael Pumpelly,
assisted by a corps of geologists, and the field of his work is the
crystalline schists of the Appalachian region, or eastern portion of the
United States, extending from northern New England to Georgia. He will
also include in his studies certain paleozoic formations which are
immediately connected with the crystalline schists and involved in their
orographic structure.
The second division for the study of this class of rocks is in charge of
Prof. Roland D. Irving, with a corps of geologists, and his field of
operation is in the Lake Superior region. It is not proposed at present to
undertake the study of the crystalline schists of the Rocky Mountain
region.
Fifth, another division has been organized for the study of the areal,
structural, and historical geology of the Appalachian region, extending
from the Atlantic, westward, to the zone which separates the mountain
region from the great valley of the Mississippi. Mr. G.K. Gilbert has
charge of this work, and has a large corps of assistants.
Sixth, it seemed desirable, partly for scientific reasons and partly for
administrative reasons, that a thorough topographic and geologic survey
should be made of the Yellowstone Park, and Mr. Arnold Hague is in charge
of the work, with a corps of assistants. When it is completed, his field
will be expanded so as to include a large part of the Rocky Mountain
region, but the extent of the field is not yet determined.
It will thus be seen that the general geologic work relating to those
areas where the terranes are composed of fossiliferous formations is very
imperfectly and incompletely organized. The reason for this is twofold:
First, the work cannot be performed very successfully until the maps are
made; second, the Geological Survey is necessarily diverting much of its
force to the construction of maps, and cannot with present appropriations
expand the geologic corps so as to extend systematic work in the field
over the entire country.
ECONOMIC GEOLOGY.
Under the organic law of the Geological Survey, investigations in economic
geology are restricted to those States and Territories in which there are
public lands; the extension of the work into the eastern portion of the
United States included only that part relating to general geology. Two
mining divisions are organized. One, in charge of Mr. George F. Becker,
with headquarters at San Francisco, California, is at the present time
engaged in the study of the quicksilver districts of California. The
other, under charge of Mr. S.F. Emmons, with headquarters at Denver,
Colorado, is engaged in studying various mining districts in that State,
including silver, gold, iron, and coal areas. Each division has a corps of
assistants. The lignite coals of the upper Missouri, also, are under
investigation by Mr. Bailey Willis, with a corps of assistants.
EMPLOYES.
The employes on the Geological Survey at the close of September, 1884,
were as follows:
Appointed by the President, by and with the advice and consent of the
Senate (Director), 1.
Appointed by the Secretary of the Interior, on the recommendation of the
Director of the Survey, 134.
Employed by the chiefs of parties in the field, 148.
APPOINTMENTS.
Three classes of appointments are made on the Survey. The statute provides
that "the scientific employes of the Geological Survey shall be selected
by the Director, subject to the approval of the Secretary of the Interior,
exclusively for their qualifications as professional experts." The
provisions of this statute apply to all those cases where scientific men
are employed who have established a reputation, and in asking for their
appointment the Director specifically states his reasons, setting forth
the work in which the person is to be employed, together with his
qualifications, especially enumerating and characterizing his published
works. On such recommendations appointments are invariably made. Young men
who have not established a reputation in scientific research are selected
through the agency of the Civil Service Commission on special examination,
the papers for which are prepared in the Geological Survey. About one-half
of the employes, however, are temporary, being engaged for services
lasting for a few days or a few months only, largely in the field, and
coming under two classes: Skilled laborers and common laborers. Such
persons are employed by the Director or by the heads of divisions, and are
discharged from the service when no longer needed. It will be seen that
the Director is responsible for the selection of the employes, directly
for those whom he recommends for appointment, and indirectly for those
selected by the Civil Service Commission, as he permanently retains in the
work. If, then, improper persons are employed, it is wholly the Director's
fault.
The appropriations made for the Geological Survey for the fiscal year
ending June 30, 1885, aggregate the sum of $504,040. This sum does not
include the amount appropriated for ethnologic researches--$40,000. Nor
are the expenses for engraving and printing paid for from the above
appropriations, but from appropriations made for the work under the
direction of the public printer. It is estimated that the amount needed
for engraving and printing for the same fiscal year will exceed $200,000.
THE RELATION OF THE GOVERNMENT SURVEY TO STATE SURVEYS.
The United States Geological Survey is on friendly relations with the
various State Surveys. Between the Government Survey and the State Survey
of New York, there is direct co-operation. The State Survey of
Pennsylvania has rendered valuable assistance to the Government Survey,
and negotiations have been entered into for closer relations and more
thorough co-operation. The State Surveys of North Carolina, Kentucky, and
Alabama are also co-operating with the Government Survey, and the director
of the Government Survey is doing all within his power to revive State
Surveys. The field for geologic research in the United States is of great
magnitude, and the best results can be accomplished only by the labors of
many scientific men engaged for a long term of years. For this reason it
is believed that surveys should be established in all of the States and
Territories. There is work enough for all, and the establishment of local
surveys would greatly assist the general work prosecuted under the
auspices of the government, and prevent it from falling into perfunctory
channels. Its vigor and health will doubtless be promoted by all thorough
local research.
It may be of interest to scientific men to know that the Director finds
that in presenting the general results, interests, and needs of the Survey
to Congress, and to Committees of Congress, a thorough appreciation of the
value of scientific research is shown by the statesmen of the country.
Questions relating to immediately economic values are asked, as they
should be; but questions relating to sound administration, wise methods of
investigation, and important scientific results are vigorously urged, and
the principle is recognized that all sound scientific research conduces to
the welfare of the people, not only by increasing knowledge, but
ultimately by affecting all the industries of the people.
* * * * *
[THE GARDEN.]
THE SUNFLOWERS.
[Illustration: FLOWER OF HELIANTHUS ARGOPHYLLUS.]
The genus Helianthus is almost entirely North-American, and for the
distinction and limitation of its species we are indebted to the labor of
Dr. Asa Gray, now universally recognized as the highest authority on North
American plants. In the recently published second part of his "Synoptical
Flora of North America" he has described thirty-nine species, six of which
are annual. The synonyms and cross-naming adopted by previous authors have
led to much confusion, which probably will not now be altogether cleared
up, for Dr. Gray warns us that the characters of some of the species are
variable, especially in cultivation. It may be added that some at least of
the species readily form hybrids. There is always more or less difficulty
with a variable genus in making garden plants fit wild specific types, but
in the following notes I have described no kinds which I have not myself
cultivated, selecting the best forms and giving them the names assigned
severally by Dr. Gray to the species to which our garden plants seem to
come nearest.
[Illustration: HELIANTHUS ARGOPHYLLUS, SHOWING HABIT OF GROWTH.]
_Helianthus multiflorus_, or, according to Asa Gray, speaking botanically,
H. decapetalus hort. var. multiflorus, is mentioned first, because it is
the subject of the colored illustration. The name multiflorus is
established by long usage, and perhaps was originally given in contrast to
the few-flowered habit of H. annuus, for the type of the species is more
floriferous than the variety of which Asa Gray says that it is "known only
in cultivation from early times, must have been derived from
decapetalus," a statement which gardeners would hardly have accepted on
less indisputable authority, as they will all think the habit and
appearance of the two plants widely different. The variety multiflorus has
several forms; the commonest form is double, the disk being filled with
ligules much shorter than those of the ray flowers, after the form of many
daisy-like composites. In this double form the day flowers are often
wanting. It is common also on old plants in poor soils to see double and
single flowers from the same root. In the single forms the size of the
flowers varies, the difference being due to cultivation as often as to
kind. I have obtained by far the finest flowers by the following
treatment: In early spring, when the young shoots are about an inch high,
cut some off, each with a portion of young root, and plant them singly in
deep rich soil, and a sheltered but not shaded situation. By August each
will have made a large bush, branching out from one stalk at the base,
with from thirty to forty flowers open at a time, each 5 inches across.
The same plants if well dressed produce good flowers the second season,
but after that the stalks become crowded, and the flowers degenerate. The
same treatment suits most of the perennial sunflowers. The following kinds
are mentioned in the order in which they occur in Asa Gray's book:
[Illustration: HELIANTHUS MULTIFLORUS, SHOWING HABIT OF GROWTH.]
ANNUALS.
_H. argophyllus_ (white-leaved, not argyrophyllus, silver-leaved, as
written in some catalogues).--An annual with woolly leaves, neater and
less coarse than H. annuus, with which it is said soon to degenerate in
gardens if grown together with it.
_H. annuus._--The well known sunflower in endless varieties, one of the
most elegant having pale lemon-colored flowers; these, too, liable to pass
into the common type if grown in the same garden.
[Illustration: HELIANTHUS ORGYALIS, SHOWING HABIT OF GROWTH IN
AUTUMN.]
_H. debilis var. cucumerifolius._--I have never seen the typical species,
but the variety was introduced a few years ago by Mr. W. Thompson, of
Ipswich, from whose seed I have grown it. It becomes 4 feet or 5 feet
high, with irregularly toothed deltoid leaves and spotted stalks, making a
widely branched bush and bearing well-shaped golden flowers more than 3
inches across, with black disks. It crosses with any perennial sunflower
that grows near it, simulating their flowers in an annual form. I had a
very fine cross with it and H. annuus, but the flowers of this produced no
good seed.
[Illustration: JERUSALEM ARTICHOKE (HELIANTHUS TUBEROSUS).]
PERENNIALS.
_H. orgyalis_ (the fathom-high sunflower).--The name is far within the
true measure, which is often 9 feet or 10 feet. A very distinct species,
increasing very slowly at the root and throwing all its growing efforts
upward. The long linear ribbon leaves, often exceeding a foot, spreading
in wavy masses round the tall stem, which has a palm-like tuft of them at
the summit, are a more ornamental feature than the flowers, which are
moderate in size and come late in the axils of the upper leaves.
[Illustration: HELIANTHUS ANNUUS GLOBULUS FISTULOSUS.]
_H. angustifolius._--A neat and elegant species, which I first raised from
seed sent by Mr. W. Thompson, of Ipswich. It has a very branching habit
quite from the base like a well-grown bush of the common wallflower. The
flowers are abundant, about 2½ inches across, with a black disk. The
plant, though a true herb, never comes up in my garden with more than one
stalk each year.
[Illustration: HELIANTHUS RIGIDUS (SYN. HARPALIUM RIGIDUM).]
_H. rigidus_ is well known as the best of the perennial sunflowers, and
has many synonyms, the commonest Harpalium rigidum. It need not be
described, but one or two things about it may be noted. The shoots, which
come up a yard or more from last year's stalk, may be transplanted as soon
as they appear without injury to the flowering, but if put back to the old
center, the soil, which should be deep and light, ought to be enriched.
The species is variable, and improved forms may be expected, as it
produces seed in England. The number of ray flowers is often very large. I
have one form which has several rows of them, nearly hiding the disk. A
variety is figured in _Botanical Magazine_, tab. 2,668, under the name of
H. atro-rubens. Another comes in the same series, tab. 2,020, as H.
diffusus. Other synonyms are H. missuricus and H. missouriensis. Its
native range extends across North America in longitude, and covers many
degrees of latitude. It likes a dry soil. In wet soil and wet seasons the
flower-stalk is apt to wither in the middle, and the bud falls over and
perishes prematurely.
[Illustration: COMMON SUNFLOWER (H. ANNUUS) SHOWING HABIT OF GROWTH.]
_H. Lætiflorus._--Under this name we grow in England a tall,
much-branched, late flowering kind, with smooth and very stout and stiff
stalks, sometimes black, sometimes green. It increases at the base of the
stalks; it makes close growth, and shows little disposition to run at the
root. The flowers are rather small, not more than 9 inches across, but so
durable and so well displayed by the numerous spreading branches as to
make the plant very useful for late decoration. I own that I cannot
identify this plant with the lætiflorus of Asa Gray, which he tells us
resembles tall forms of H. rigidus, with rough stalks, and bears flowers
with numerous rays 1½ inches long.
[Illustration: FLOWER OF HELIANTHUS ANNUUS.]
_H. occidentalis._--Recently introduced by Mr. W. Thompson, of Ipswich,
who gave me the plant two years ago. It is a neat species, growing about 2
feet high, well branched, and producing at the end of July abundance of
flowers about 2 inches across. The lower leaves are small and broad, with
long stalks, ovate in form.
[Illustration: HELIANTHUS MULTIFLORUS FL-PL.]
_H. mollis_, so called from the soft white down with which the leaves are
covered, grows about 4 feet high. Leaves large, ovate, and sessile; growth
of the plant upright, with hardly any branches; flowers pale yellow, about
3 inches across, not very ornamental. Cultivated at Kew, whence I had it.
_H. giganteus_ grows 10 feet high; stem much branched and disposed to
curve. Flowers about 2½ inches across, produced abundantly in August; rays
narrow and pointed, cupped, with the ends turning outward; leaves
lanceolate and sessile; rootstock creeping, forming tuberous thickenings
at the base of the stems, which Asa Gray tells us were "the Indian potato
of the Assiniboine tribe," mentioned by Douglas, who called the plant H.
tuberosus.
[Illustration: FULL SIZED FLOWER OF HELIANTHUS MULTIFLORUS.]
_H. maximiliani._--Half the height of the last, which it resembles, but
the stem is stouter, the leaves larger, as are also the flowers, which are
produced later. It is not so floriferous and ornamental as the last.
_H. lævigatus._--Smooth stalked, very distinct, does not spread at the
roots, which are composed of finer fibers than those of most of the genus;
stalks slender and black, growing closely together, branched near the
summit, 5 feet high; leaves narrowly lanceolate and acute; flowers
plentiful and about 2 inches across; rays few, and disk small.
We are warned that the following species are "difficult of extrication,"
either confluent or mixed by intercrossing.
_H. doronicoides._--I place this the third in merit among perennial
sunflowers, H. rigidus and H. multiflorus being first and second. It is 6
feet or 7 feet high, upright in growth, with many stalks. Flowers 3½
inches across, produced from the end of July to the end of September,
bright golden yellow; leaves large, ovate, tapering from the middle to
both ends; stalk leaves sessile and nearly connate, that is, clasping the
stalk by their opposite base. The plant spreads rapidly by running
rootstocks, and ripens seed in abundance. Figured as H. pubescens in
_Botanical Magazine_, tab. 2,778.
_H. divaricatus_ resembles the last, but is inferior, being a smaller
plant in all parts, especially in the flowers, which come out a month
later. The cauline leaves are stalked and diverge widely, which habit
gives its name to the plant. A casual observer would hardly notice the
difference between this species and the last, but when grown together the
superiority of doronicoides as a garden plant is at once evident.
_H. strumosus._--Fully 6 feet high; growth upright; rootstock less
spreading than the last two; leaves on very short stalks, broadest at the
base, ovate tapering by a long narrow point; flower disk narrow, but rays
large and orange-yellow; flowers showy, 3 inches across; they come out
late in August. I had this plant from Kew. The shape of the leaves would
have led me rather to refer it to H. trachelifolius, a closely allied
species.
_H. decapetalus._--Five feet high; flowers from end of July; makes a dense
forest of weak, slender stalks, much branched at the top; spreads fast;
leaves serrate, oblong-ovate, rather large; flowers abundant, pale yellow,
about 2 inches across; rays nearly always more than ten, in spite of the
name.
_H. tuberosus._--The well-known Jerusalem artichoke; not a plant grown for
ornament, being too coarse and late in flowering, but several things in
its history may be mentioned, as Dr. Asa Gray has spent labor and study
over it. It is believed to have been cultivated by the natives before the
discovery of America, and the edible tubers are thought to be a
development of cultivation. Forms of it without tuberous roots are found
wild, but whether indigenous to the place or degenerate from cultivation
was for long uncertain. Several species of Helianthus have a tendency to
produce similar fleshy tubers at the top of the roots. Dr. Gray used to
refer the origin of this species to H. doronicoides, but it is now
believed by him to be a distinct species, though one of which it is
difficult to identify with certainty the typical form.
I omitted to say that the word Helianthus is Greek for sunflower. After
several years' careful observation, I believe the notion that the flowers
keep their face to the sun is quite a delusion.
Edge Hall. C. WOLLEY DOD.
* * * * *
A QUICK FILTER.--The _Druggists Circular_ recommends chamois skin, free
from thin places; cut it of the desired size; wash it in a weak solution
of sal soda, or any alkali, to remove the grease, and rinse thoroughly in
cold water before using.
Tinctures, elixirs, sirups, and even mucilages are filtered rapidly. A
pint of the thickest sirup will run through in four or five minutes. By
washing thoroughly after each time of using, it will last a long time.
* * * * *
LYE'S FUCHSIAS.
The group of fuchsias shown in our engraving represents a collection of
nine specimens raised and exhibited by that well known cultivator, Mr.
James Lye, of Clyffe Hall Gardens, Market Lavington, at an exhibition held
in Bath in September last, and which received the first prize in the
premier class for that number of plants. For many years past Mr. Lye has
exhibited fuchsias at exhibitions held at Bath, Trowbridge, Devizes,
Calne, Chippenham, and elsewhere; on all occasions staging specimens of a
high order of merit; but the plants appearing in our illustration were
universally regarded as the best he had ever placed in an exhibition tent.
So much were the committee of the Bath show pleased with the specimens
that they engaged the services of a photographer to make a picture of them
on the spot; but after being two hours making the attempt, no satisfactory
result occurred. After the plants were taken back to Clyffe Hall, they
were photographed as seen in the illustration. Some idea of their height
and dimensions can be realized by a comparison with the stature of Mr.
Lye, who is standing by his plants, and who is of average height. It
should be mentioned that previous to being photographed they had traveled
by road from Market Lavington to Bath and back, a distance of 52 miles, in
addition to having been exhibited two days. They returned to their home
apparently little the worse for wear, which immunity from harm is no doubt
owing to the admirable system of tying adopted by Mr. Lye. It is sometimes
said that the act of trying in the flowering shoots in this manner gives
the plants a somewhat severely formal appearance, but there is an
abundance of healthy foliage and a wonderful profusion of finely developed
flowers, showing the most careful and painstaking cultivation. It is only
those who are privileged to see these unrivaled plants who can appreciate
them at their proper worth.
It has been stated already that the varieties figured are all of Mr. Lye's
own raising, which facts attests to the value of his seedlings, many of
which he has produced. Four of these are dark varieties, viz., Bountiful,
Charming, Elegance, and the Hon. Mrs. Hay--the latter one of the oldest,
but one of the freest, and scarcely without an equal for its great freedom
of bloom. The remaining five are light varieties, viz., Lye's Favorite,
Harriet Lye, Star of Wilts, Pink Perfection, and Beauty of the West.
[Illustration: MR. LYE'S FUSCHIAS.]
The specimens figured average from two to five years of age. It is really
marvelous what Mr. Lye can do with a fuchsia in two years; and lest it
might be supposed that he has plenty of glass accommodation, and can keep
his plants under glass continuously, it is due to him it should be stated
that he is very deficient in house accommodation, having but two small
houses, in one of which (an old house) he winters his plants and brings
them on until he can place them with safety in the open air in early
summer. His method of treating the specimens as set forth in his own words
may prove helpful to some of our readers: "After the plants have done
flowering, say about the third week in October, I cut them back into the
shape best fitted to form symmetrical specimens, and keep them dry for a
week or ten days, to check the bleeding of sap which follows; after that I
give a little water just to start them into growth, so as to make shoots
about three-quarters of an inch in length, in order to keep the old wood
active and living. I keep them in a cold house, and give but very little
water until the first or second week in February, when I shake the old
soil from the roots, and re-pot them into a fresh compost made up of three
parts good loam, one part well decomposed manure, and one part leaf-mould
and peat, with a good bit of silver or sea sand to keep it open. In order
to make large specimens, they are shifted as soon as the pots are filled
with roots. About the first week in June I place them out of doors on a
border somewhat sheltered, and syringe the plants freely every day during
hot weather to keep the foliage clean and healthy. I top them back till
about seven or eight weeks before I want to show them, according to the
requirements of the variety, as some of them require it to be done more
freely than others. I give them liquid manure, using what I get from the
cows, which with some soot is put into a tub, and allowed to stand a week
or ten days before using, and I give them a good dose once a week as they
show signs of flowering."
In order to preserve his plants from the effects of hail and very heavy
rains, a rough framework is erected, and over this is stretched some
floral shading, which can be readily removed when required; it also serves
the purpose of shading the plants from the sun in very hot and scorching
weather.
During his career as an exhibitor of fuchsias Mr. Lye has taken nearly one
hundred first prizes--a measure of success which fully justifies the
bestowal of the title of being the Champion Fuchsia Grower of his
day.--_R.D. in The Gardeners' Chronicle_.
* * * * *
A catalogue, containing brief notices of many important scientific papers
heretofore published in the SUPPLEMENT, may be had gratis at this office.
* * * * *
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*** End of this LibraryBlog Digital Book "Scientific American Supplement, No. 484, April 11, 1885" ***
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