Scientific American Supplement, No. 324, March 18, 1882 by Various

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Produced by Olaf Voss, Don Kretz, Juliet Sutherland,
Charles Franks and the DP Team

[Illustration]

SCIENTIFIC AMERICAN SUPPLEMENT NO. 324

NEW YORK, MARCH 18, 1882

Scientific American Supplement. Vol. XIII, No. 324.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

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TABLE OF CONTENTS.

I. ENGINEERING AND MECHANICS--Machine Tools for Boiler Makers.
2 figures.--Improved boiler plate radial drill.--Improved
boiler plate bending roller.

Modern Ordnance. By COLONEL MAITLAND.--Rifled cannon.--Built
guns.--Steel castings.--Breech loading.--Long guns.--Slow
burning of powder.--Breech closers.--Projectiles.--Destructive
power of guns.

Oscillating Cylinder Locomotive. 2 figures.--Shaw's oscillating
cylinder locomotive.

Gas Motors and Producers. By C. W. SIEMENS--2 figures.

The Bazin System of Dredging. By A. A. LANGLEY.--3 figures.

II. CHEMISTRY.--On the Mydriatic Alkaloids. By ALBERT LADENBERG.
--I. Atropine.--II. The Atropine of Datura Stramonium.
--III. Hyoscyamine from Hyoscyamus.

Detection of Small Quantities of Morphia. By A. JORISSEN.

The Estimation of Manganese by Titration. By C. G. SARNSTROM.

On the Estimation and Separation of Manganese. By NELSON
H. DARTON.

Delicate Test for Oxygen.

Determination of Small Quantities of Arsenic in Sulphur. By H.
SCHAEPPI.

III. BIOLOGY, ETC.--Researches on Animals Containing Chlorophyl.
--Abstract of a long and valuable paper "On the Nature and Functions
of the Yellow Cells of Radiolarians and Coelenterates," read
to the Royal Society of Edinburgh. By PATRICK GEDDES.

The Hibernation of Animals, An interesting review of the winter
habits of some of our familiar animals, insects, etc.

IV. HORTICULTURE, SILK CULTURE, ETC.--How to Plant Trees.
By N. ROBERTSON.

The Growth of Palms.

The Future of Silk Culture in the United States. Report of
United States Consul Peixotto, of Lyons. A valuable and encouraging
summary of the conditions and prospects of silk culture
in the United States.

V. TECHNOLOGY, ETC.--Compressed Oil Gas for Lighting Cars,
Steamboats, and Buoys. An elaborate description of the apparatus
and appliances of the Pintsch system of illumination. 14
figures. Elevation and plan of works.--Cars.--Locomotive and car
lamps.--Buoys.--Regulations, etc.

VI. ART, ARCHITECTURE, ETC.--Cast Iron in Architecture.

VII. ELECTRICITY, MAGNETISM, ETC.--On the Mechanical Production
of Electric Currents. 12 figures.

Rousse's Secondary Battery.

VIII. MISCELLANEOUS.--Dangers from Lightning in Blasting.

The Tincal Trade of Asia.

Sir W. Palliser. Obituary and summary of his inventions.

The Tides. Influence of the tides upon the history of the earth.

Drilling Glass.

* * * * *

MACHINE TOOLS FOR BOILER-MAKERS.

We give this week an engraving of a radial drilling machine designed
especially for the use of boiler-makers, this machine, together with the
plate bending rolls, forming portion of a plant constructed for Messrs.
Beesley and Sons, boiler makers, of Barrow-in-Furness.

[Illustration: IMPROVED BOILER PLATERADIAL DRILL.]

This radial drill, which is a tool of substantial proportions, is
adapted not only for ordinary drilling work, but also for turning the
ends of boiler shells, for cutting out of flue holes tube boring, etc.
As will be seen from our engraving, the pillar which supports the radial
arm is mounted on a massive baseplate, which also carries a circular
table 6 ft. in diameter, this table having a worm-wheel cast on it
as shown. This table is driven by a worm gearing into the wheel just
mentioned. On this table boiler ends up to 8 ft. in diameter can be
turned up, the turning tool being carried by a slide rest, which is
mounted on the main baseplate, as shown, and which is adjustable
vertically and radially.

For cutting out flue holes a steel boring head is employed, this head
having a round end which fits into the center of the table. When this
work is being done the radial arm is brought into the lowest position.
Flue holes 40 in. in diameter can thus be cut out.

The machine has a 4 in. steel spindle with self-acting variable feed
motion through a range of 10 in., and the radial arm is raised or
lowered by power through a range of 2 ft. 8 in. When the arm is in its
highest position there is room for a piece of work 4 ft. high between
the circular table and the lower end of the spindle. The circular
table serves as a compound table for ordinary work, and the machine is
altogether a very useful one for boiler-makers.

The plate-bending rolls, which are illustrated on first page, are 10 ft.
long, and are made of wrought iron, the top roll being 12 in. and the
two bottom rolls 10 in. in diameter. Each of the bottom rolls carries
at its end a large spur-wheel, these spur-wheels, which are on opposite
sides of the machine, each gearing into a pinion on a shaft which runs
from end to end below the rolls, and which is itself geared to the shaft
carrying the belt pulleys, as shown. This is a very simple and direct
mode of driving, and avoids the necessity for small wheels on the rolls.
There is no swing frame, but the top roll is arranged to draw through
between the arms of the spur-wheels, a very substantially framed machine
being thus obtained.

[Illustration: IMPROVED BOILER PLATE BENDING ROLLER.]

The chief novelty in the machine is the additional roll provided
under the ordinary bottom rolls. This extra roll, which is used for
straightening old plates and for bending small tubes, pipes, etc., is
made of steel, and is 7 in. in diameter by 5 ft. long. It is provided
with a swing frame at one end to allow of taking-off pipes when bent,
etc., and it is altogether a very useful addition.

The machine we illustrate weighs 11 tons, and is all self-contained, the
standards being mounted on a strong bedplate, which also carries the
bearings for the shaft with fast and loose pulleys, belt gear, etc. Thus
no foundation is required.--_Engineering_.

* * * * *

MODERN ORDNANCE.

[Footnote: A paper read Feb. 8, 1882, before the Society of Arts,
London.]

By COLONEL MAITLAND.

A great change has lately been taking place throughout Europe in the
matter of armaments. Artillery knowledge has been advancing "by leaps
and bounds;" and all the chief nations are vying with each other in the
perfection of their _matériel_ of war. As a readiness to fight is the
best insurance for peace, it behooves us to see from time to time how we
stand, and the present moment is a peculiarly suitable one for taking
stock of our powers and capabilities. I propose, therefore, to give you,
this evening, a brief sketch of the principles of manufacture of
modern guns, at home and abroad, concluding with a few words on their
employment and power.

The introduction of rifled cannon into practical use, about twenty years
ago, caused a complete revolution in the art of gun-making. Cast iron
and bronze were found no longer suitable for the purpose. Cast iron was
too brittle to sustain the pressure of the powder gas, when its duration
was increased by the use of elongated projectiles; while the softness of
bronze was ill adapted to retain the nicety of form required by accurate
rifling.

From among a cloud of proposals, experiments, and inventions, two
great systems at length disentangled themselves. They were the
English construction of built-up wrought iron coils, and the Prussian
construction of solid steel castings.

Wrought-iron, as you are all aware, is nearly pure iron, containing but
a trace of carbon. Steel, as used for guns, contains from 0.3 to 0.5 per
cent of carbon; the larger the quantity of carbon, the harder the steel.
Since the early days of which I am now speaking, great improvement has
taken place in the qualities of both materials, but more especially in
that of steel. Still the same general characteristics were to be noted,
and it may be broadly stated, that England chose confessedly the weaker
material, as being more under control, cheaper, and safer to intrust
with the lives of men; while Prussia selected the stronger but less
manageable substance, in the hope of improving its uniformity, and
rendering it thoroughly trustworthy. The difference in strength, when
both are sound, is great. Roughly, gun steel is about twice as strong as
wrought iron.

I must now say a few words on the nature of the strains to which a piece
of ordnance is subjected when fired. Gunpowder is commonly termed an
explosive, but this hardly represents its qualities accurately. With a
true explosive, such as gun-cotton, nitro glycerine and its compounds,
detonation and conversion of the whole into gas are practically
instantaneous, whatever the size of the mass; while, with gunpowder,
only the exterior of the grain or lump burns and gives off gas, so that
the larger the grain the slower the combustion. The products consist of
liquids and gases. The gas, when cooled down to ordinary temperature,
occupies about 280 times the volume of the powder. At the moment of
combustion, it is enormously expanded by heat, and its volume is
probably somewhat about 6,000 times that of the powder. I have here a
few specimens of the powders used for different sizes of guns, rising
from the fine grain of the mountain gun to the large prisms and
cylinders fired in our heavy ordnance. You will readily perceive that,
with the fine-grained powders, the rapid combustion turned the whole
charge into gas before the projectile could move far away from its seat,
setting up a high pressure which acted violently on both gun and shot,
so that a short, sharp strain, approximating to a blow, had to be
guarded against.

With the large slow-bursting powders now used, long heavy shells move
quietly off under the impulse of a gradual evolution of gas, the
presence of which continues to increase till the projectile has moved a
foot or more; then ensues a contest between the increasing volume of the
gas, tending to raise the pressure, and the growing space behind the
advancing shot, tending to relieve it. As artillery science progresses,
so does the duration of this contest extend further along the bore
of the gun toward the great desideratum, a low maximum pressure long
sustained.

When quick burning powder was used for ordnance, the pressures were
short and sharp; the metal in immediate proximity to the charge was
called upon to undergo severe strains, which had scarcely time to reach
the more distant portions of the gun at all; the exterior was not nearly
so much strained as the interior. In order to obviate this defect, and
to bring the exterior of the gun into play, the system of building up
guns of successive tubes was introduced. These tubes were put one over
the other in a state of tension produced by "shrinkage." This term is
applied to the process of expanding a tube by the application of heat,
and in that condition fitting it over a tube larger than the inner
diameter of the outer tube when cold. When the outer tube cools it
contracts on the inner tube and clutches it fast. The wrought-iron guns
of England have all been put together in this manner.

Prussia at first relied on the superior strength of solid castings
of steel to withstand the explosive strain, but at length found the
necessity for re-enforcing them with hoops of the same material, shrunk
on the body of the piece.

The grand principle of shrinkage enables the gunmaker to bring into play
the strength of the exterior of the gun, even with quick powders, and to
a still greater extent as the duration of the strain increases with the
progress of powder manufacture. Thus, taking our largest muzzle-loaders
designed a few years ago, the thin steel lining tube, which forms an
excellent surface, is compressed considerably by the wrought-iron breech
coil holding it, which, in its turn, is compressed by the massive
exterior coil. When the gun is fired, the strain is transmitted at once,
or nearly at once, to the breech coil, and thence more slowly to the
outer one. Now, as the duration of the pressure increases, owing to the
use of larger charges of slower burning powder, it is evident that the
more complete and effective will be the transmission of the strain to
the exterior, and, consequently, the further into the body of the
gun, starting from the bore, and traveling outward, does it become
advantageous to employ the stronger material. Hence, in England, we
had reason to congratulate ourselves on the certainty and cheapness
of manufacture of wrought iron coils, as long as moderate charges
of comparatively quick burning powder were employed, and as long as
adherence to a muzzle-loading system permitted the projectiles to move
away at an early period of the combustion of the charge. Then the
pressures, though sharp, were of short duration, and were not thoroughly
transmitted through the body of the gun, so that the solidity, mass,
and compression of the surrounding coils proved usually sufficient to
support the interior lining. Now that breech-loading and slow powders
have been introduced, these conditions have been changed. The strains,
though less severe, and less tending to explosive rupture, last longer,
and are more fully transmitted through the body of the gun. Sheer
strength of material now tells more, and signs have not been wanting
that coils of wrought iron afford insufficient support to the lining.
It becomes, therefore, advantageous to thicken the inner tube, and to
support it with a steel breech piece. Carrying this principle further,
we shall be led to substitute the stronger for the weaker metal
throughout the piece. This has been done by the Germans in the first
instance, and recently by the French also. It is probable that we shall
follow the same course. When I say "probable," I intentionally guard
myself against uttering a prediction. It is never safe to prophesy,
unless you know, as the American humorist puts it. And in this case we
do not know, for a very dangerous rival, once defeated, but now full of
renewed vigor, has entered the lists against forged steel as a material
for ordnance. This rival's name is _wire_. Tempered steel wires can
be made of extraordinary strength. A piece of round section, only one
thirty-fifth of an inch in diameter, will just sustain a heavy man.

If, now, a steel tube, suitable for the lining of a gun, be prepared by
having wire wound round it very tightly, layer over layer, it will be
compressed as the winding proceeds, and the tension of the wire will act
as shrinkage. You will readily understand that a gun can be thus formed,
having enormous strength to resist bursting. Unfortunately, the wires
have no cohesion with one another, and the great difficulty with
construction of this kind is to obtain what gun-makers call end
strength. It is of but little use to make your walls strong enough, if
the first round blows the breech out. In the early days of wire this was
what happened, and Mr. Longridge, who invented the system, was compelled
to abandon it.

Lately, methods have been devised in France, by M. Schultz; at Elswick,
by Sir W.G. Armstrong & Co.; and at Woolwich, by ourselves, for getting
end strength with wire guns. They are all in the experimental stage;
they may prove successful; but I prefer not to prophesy at present.

The diagrams on the wall show the general construction of the modern
German, French, and English heavy breech-loading guns. The Germans have
a tube, a jacket, and hoops. The French, a thick tube or body, and
hoops. The English, a tube, a jacket, and an overcoat, as it may be
called. In each system of construction, the whole of the wall of the gun
comes into play to resist the transverse bursting strain of the charge.

The longitudinal or end strength varies: thus, in the German guns, the
tube and hoops do nothing--the jacket is considered sufficient. The
French construction relies entirely on the thick body, while the English
method aims at utilizing the whole section of the gun, both ways.
Of course, if the others are strong enough, there is no particular
advantage in this; and it is by no means improbable that eventually we
shall find it cheaper, and equally good, to substitute hoops for the
"overcoat."

I fear I have detained you a long time over construction, but it is both
instructive and interesting to note that certain well defined points
of contact now exist between all the great systems. Thus, a surface of
steel inside the bore is common to all, and the general use of steel is
spreading fast. Shrinkage, again, is now everywhere employed, and
such differences as still exist are matters rather of detail than of
principle, as far as systems of construction are concerned.

We now come to a part of the question which has long been hotly debated
in this country, and about which an immense quantity of matter has been
both spoken and written on opposite sides--I mean muzzle loading and
breech-loading. The controversy has been a remarkable one, and, perhaps,
the most remarkable part of it has been the circumstance that while
there is now little doubt that the advocates of breech-loading were on
the right side, their reasons were for the most part fallacious. Thus,
they commonly stated that a gun loaded at the breech could be more
rapidly fired than one loaded at the muzzle. Now, this was certainly not
the case, at any rate, with the comparatively short guns which were
made on both systems a few years ago. The public were acquainted with
breech-loaders only in the form of sporting guns and rifles, and argued
from them. The muzzle-loading thirty eight ton guns were fired in a
casemate at Shoeburyness repeatedly in less than twenty minutes for ten
rounds, with careful aiming. No breech-loader of corresponding size has,
I think, ever beaten that rate. With field-guns in the open, the No. 1
of the detachment can aim his muzzle loader while it is being loaded,
while he must wait to do so till loading at the breech is completed.
Again, it was freely stated that, with breech-loaders greater protection
was afforded to the gunners than with the muzzle-loaders. This entirely
depends on how the guns are mounted. If in siege works or _en
barbette_, it is much easier to load a muzzle loader under cover than a
breech-loader. But I need not traverse the old ground all over again. It
is sufficient for me to say here, that the real cause which has rendered
breech-loading an absolute necessity is the improvement which has been
made in the powder. You witnessed a few minutes ago the change which
took place in the action of fired gunpowder when the grains were
enlarged. You will readily understand that nearly the whole of a quick
burning charge was converted into gas before the shot had time to start;
suppose for the moment that the combustion was really instantaneous.
Then we have a bore, say sixteen diameters long, with the cartridge
occupying a length of, say, two diameters.

The pressure of the gas causes the shot to move. The greater the
pressure, the greater the impulse given. As the shot advances, the
pressure lessens; and it lessens in proportion to the distance the shot
proceeds. Thus, when the shot has proceeded a distance equal to the
length of the cartridge, the space occupied by the gas is doubled, and
its original pressure is halved. As the shot travels another cartridge
length, the space occupied by the gas is trebled, and its pressure will
be but one-third of the original amount. When the shot arrives at the
muzzle--that is, at eight times the length of the cartridge from the
breech--the pressure will be but one ninth of that originally set up.
Remember, this is on the supposition that the powder has been entirely
converted into gas before the shot begins to move.

Now, suppose the powder to be of a slow-burning kind, and assume that
only one-third of it has been converted into gas before the shot starts,
then the remaining two-thirds will be giving off additional gas as the
shot travels through the bore. Instead, therefore, of the pressure
falling rapidly, as the shot approaches the muzzle, the increasing
quantity of gas tends to make up for the increasing space holding it.
You will at once perceive that the slower the combustion of the powder
the less difference there will be in the pressure exerted by the gas at
the breech and at the muzzle, and the greater will be the advantage,
in point of velocity, of lengthening the bore, and so keeping the shot
under the influence of the pressure. Hence, all recent improvement has
tended toward larger charges of slower burning powder, and increased
length of bore. And it is evident that the longer the bore of the gun,
the greater is the convenience of putting the charge in behind, instead
of having to ram it home from the front. I may here remark, that the
increased length of gun necessary to produce the best effect is causing
even those who have possessed breech-loaders for many years to rearm,
just as completely as we are now beginning to do. All the old short
breech loading guns are becoming obsolete. Another great advantage of
breech-loading is the facility afforded for enlarging the powder chamber
of the gun, so that a comparatively short, thick cartridge may be I
employed, without any definite restriction due to the size of the bore.

There is yet one more point in which breech-loading has recently been
found, in the Royal Gun Factory, to possess a great advantage over
muzzle-loading as regards ballistic effect. With a shot loaded from the
front, it is clear that it must be smaller all over than the bore, or it
would not pass down to its seat. A shot thrust in from behind, on the
contrary, may be furnished with a band or sheath of comparatively soft
metal larger than the bore; the gas then acting on the base of the
projectile, forces the band through the grooves, sealing the escape,
entering the projectile, and, to a great extent, mitigating the erosion
of surface. This is, of course, universally known. It is also pretty
generally known among artillerists that the effect of the resistance
offered by the band or sheathing on the powder is to cause more complete
combustion of the charge before the shot moves, and therefore to raise
the velocity and the pressure. But I believe it escaped notice, till
observed in May, 1880, in the Royal Gun Factory, that this circumstance
affords a most steady and convenient mode of regulating the consumption
of the charge, so as to obtain the best results with the powder
employed.

Supposing the projectile to start, as in a muzzle loader, without
offering any resistance beyond that due to inertia, it is necessary to
employ a powder which shall burn quickly enough to give off most of
its gas before the shot has proceeded far down the bore; otherwise the
velocity at the muzzle will be low. To control this comparatively quick
burning powder, a large air space is given to the cartridge, which,
therefore, is placed in a chamber considerably too big for it.
Supposing, on the other hand, the projectile to be furnished with a
stout band, giving a high resistance to initial motion, a much slower
powder can be used, since the combustion proceeds as if in a closed
vessel, until sufficient pressure is developed to overcome the
resistance of the band. This enables us to put a larger quantity of
slower burning powder into the chamber, and in fact to use, instead of a
space filled with air, a space filled with powder giving off gas, which
comes into play as the projectile travels down the bore. Thus, while not
exceeding the intended pressure at the breech, the pressure toward the
muzzle is kept up, and the velocity very materially increased. Following
this principle to this conclusion, it will be found that the perfect
charge for a gun will be one which exactly fills the chamber, and which
is composed of a powder rather too slow to give the pressure for which
the gun is designed, supposing the shot to move off freely. The powder
should be so much too slow as to require for its full development the
holding power of a band which is just strong enough to give rotation to
the shot.

Having settled that the gun of the future is to be a breech-loader,
we have next to consider what system of closing the breech is to be
adopted.

The German guns are provided with a round backed wedge, which is pushed
in from the side of the breech, and forced firmly home by a screw
provided with handles; the face of the wedge is fitted with an easily
removable flat plate, which abuts against a Broad well ring, let into
a recess in the end of the bore. On firing, the gas presses the ring
firmly against the flat plate, and renders escape impossible as long as
the surfaces remain uninjured. When they become worn, the ring and
plate can be exchanged in a few minutes. Mr. Vavasseur, of Southwark,
constructs his guns on a very similar plan. In the French guns, and our
modern ones, the bore is continued to the rear extremity of the piece,
the breech end forming an intermittent screw, that is, a screw having
the threads intermittently left and slotted away. The breech block has
a similarly cut screw on it, so that when the slots in the block
correspond with the untouched threads in the gun, the block can be
pushed straight in, and the threads made to engage by part of a
revolution. In the French Marine the escape of gas is stopped very much
as in Krupp's system; a Broadwell ring is let into a recess in the end
of the bore, and a plate on the face of the breech-block abuts against
it.

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