Scientific American Supplement, No. 586, March 26, 1887 online

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The proof of the Elswick gun is mounted on a carriage turned out by the
Royal Carriage Department, under Colonel Close. This carriage is made on
bogies so as to run on rails passing easily round curves of 50 ft. radius.
The gun is fired on an inclined length of rails, the recoil presses of the
carriage first receiving the shock and reducing the recoil. The carriage is
made to lift into the government barge, so as to go easily to Shoeburyness
or elsewhere. It can be altered so as to provide for turning, and it allows
the piece to be fired at angles of elevation up to 24 deg. The cheeks of
the carriage are made to open and close, so as to take the 12 in. gun and
larger pieces. The steel castings for it are supplied from the Stanners
Close Steel Works.

[Illustration: FIG. 4.]

The first round was fired at about noon. The charge was only 598 lb.,
consisting of four charges of 112 lb. and one of 130 lb. of Waltham Abbey
brown prism No. 1 powder. The proof shot weighs, like the service
projectile, 1,800 lb. Thus fired, the gun recoiled nearly 4 ft. on the
press, and the carriage ran back on the rails about 50 ft. The projectile
had a velocity of 1,685 ft. per second, and entered about 52 ft. into the
butt. We cannot yet give the pressure, but unquestionably it was a low one.
The charges as the firing continues will be increased in successive rounds
up to the full 900 lb. charge.

Figs. 1 and 2 show the mounting of the 110½ ton gun in the barbette towers
of the Benbow. The gun is held down on the bed by steel bands and recoils
in its bed on the slide (vide Fig. 2). The latter is hinged or pivoted in
front and is elevated by elevating ram, shown in Fig. 2. When the slide is
fully down, the gun is in the loading position. The ammunition lift brings
up the projectile and charge, which latter is subdivided, like those
employed in the German guns, in succession to the breech, the hydraulic
rammer forcing them home.

[Illustration: FIG. 5.]

[Illustration: FIG. 6.]

The simplicity of the arrangement is apparent. The recoil always acts
parallel to the slide. This is much better than allowing its direction to
be affected by elevation, and the distributed hold of the steel bands is
preferable to the single attachment at trunnions. Theoretically, the recoil
is not so perfectly met as in some of the earlier Elswick designs, in which
the presses were brought opposite to the trunnions, so that they acted
symmetrically on each side of the center of resistance. The barbette tower
is covered by a steel plate, shown in Fig. 1, fitting close to the gun
slide, so that the only opening is that behind the breech when the gun is
in the forward position, and this is closed as it recoils.

The only man of the detachment even partly exposed is the number one, while
laying the gun, and in that position he is nearly covered by the gun and
fittings. Common shell, shrapnel shell, and steel armor-piercing
projectiles, have been approved for the 110½ ton gun. The common shell is
shown in Fig. 3. Like the common shell for all the larger natures of new
type guns, it is made of steel. It has been found necessary to support the
core used in casting these projectiles at both ends. Consequently, there is
a screw plug at the base as well as at the apex. The hole at the base is
used as a filling hole for the insertion of the bursting charge, which
consists of 179 lb. of powder, the total weight of the filled shell being
1,800 lb.

[Illustration: FIG. 3.]

[Illustration: FIG. 7.]

The apex has a screw plug of larger diameter than that of the fuse. This is
shown in Fig. 4. The fuse is a direct action one. The needle, B, is held in
the center of a copper disk, C C, and is safe against explosion until it is
actually brought into contact with an object, when it is forced down,
igniting a patch of cap composition and the magazine at A, and so firing
the bursting charge of the shell below. E E E are each priming charges of
seven grains of pistol powder, made up in shalloon bags to insure the
ignition of the bursting charge, which is in a bag of serge and shalloon

The use of this fuse involves the curious question of the physical
conditions now existing in the discharge of our projectiles by slow burning
powder. The forward movement of the shell is now so gradual that the
inertia of a pellet is only sufficient to shear a wire of one-tenth the
strength of that which might formerly have been sheared by a similar pellet
in an old type gun with quick burning powder. Consequently, in many cases,
it is found better not to depend on a suspending wire thus sheared, but to
adopt direct action. The fuse in question would, we believe, act even on
graze, at any angle over 10°. Probably at less angles than 10° it would not
explode against water, which would be an advantage in firing at ships.

Shells so gently put in motion, and having no windage, might be made, it
might naturally be supposed, singularly thin, and the adoption of steel in
place of iron calls for some explanation. The reason is that it has been
found that common shells break up against masonry, instead of penetrating
it, when fired from these large high velocity guns.

The shrapnel shell is shown at Fig. 5. Like the common shell, it is made of
steel, and is of the general form of the pattern of General Boxer, with
wooden head, central tube, and bursting charge in the base. It contains
2,300 four ounce sand shots and an 8 lb. bursting charge. It weighs 1,800
lb. The fuse is time and percussion. It is shown in Figs. 6 and 6A. It
closely resembles the original Armstrong time and percussion pattern.

[Illustration: FIG. 6A.]

The action is as follows: The ignition pellet, A, which is ordinarily held
by a safety pin, is, after the withdrawal of the latter, only held by a
fine, suspending wire, which is sheared by the inertia of the pellet on
discharge, a needle lighting a percussion patch of composition and the
composition ring, B B, which burns round at a given rate until it reaches
the communication passage, C, when it flashes through the percussion
pellet, E, and ignites the magazine, D, and so ignites the primer shown in
Fig. 6, flashes down the central tube of the shell, and explodes the
bursting charge in the base, Fig. 5. The length of time during which the
fuse burns depends on how far the composition ring is turned round, and
what length it consequently has to burn before it reaches the communication
passage, C. If the fuse should be set too long, or from any other cause
the shell strikes before the fuse fires the charge, the percussion action
fires the shell on graze by the following arrangement: The heavy metal
piece containing the magazine, D, constitutes a striker, which is held in
place by a plain ball, G, near the axis of the fuse and by a safety pellet,
H. On first movement in the gun, this latter by inertia shears a suspending
wire and leaves the ball free to escape above it, which it does by
centrifugal force, leaving the magazine striker, D, free to fire itself by
momentum on the needle shown above it, on impact. There is a second safety
arrangement, not shown in the figure, consisting of a cross pin, held by a
weak spiral spring, which is compressed by centrifugal force during flight,
leaving the magazine pellet free to act, as above described, on impact.

The armor-piercing projectile is shown in Fig. 7. It is to be made of
forged steel, and supplied by Elswick. In appearance it very closely
resembles those fired from the 100 ton gun at Spezia, but if it is made on
the Firmini system, it will differ from it in the composition of its metal,
inasmuch as it will contain a large proportion of chromium, probably from 1
to 2 per cent., whereas an analysis of Krupp's shell gives none. In fact,
as Krupp's agent at Spezia predicted, the analysis is less instructive than
we could wish. - _The Engineer_.

* * * * *


The industrial world has reason to feel considerable interest in any
economical method of traction on railways, owing to the influence which
cost of transportation has upon the price of produce. We give a description
of the gas engine invented by Mr. Emmanuel Stevens. Many experiments have
been made both at Berlin and Liege during the past few years. They all
failed, owing to the impossibility the builders encountered in securing
sufficient speed.

The Stevens engine does not present this defect, as will be seen. It has
the appearance of an ordinary street car entirely inclosed, showing none of
the machinery from without. On the interior is a Koerting gas motor of six
horse power, which is a sufficiently well known type not to require a
description. In the experiment which we saw, the motor was supplied with a
mixture of gas and air, obtained by the evaporation of naphtha. On the
shaft of the motor are fixed two pulleys of different sizes, which give the
engine two rates of speed, one of three miles and the other of 8½ miles an
hour. Between these two pulleys is a friction socket, by which either rate
of speed may be secured.

The power is transmitted from one of the pulleys by a rubber belt to an
intermediate shaft, which carries a toothed wheel that transmits the power
to the axle by means of an endless chain. On this axle are three conical
gear wheels, two of which are furnished with hooked teeth, and the third
with wooden projections and fixed permanently in place. This arrangement
enables the engine to be moved forward or backward according as it is
thrown in right or left gear. When the conical pinions are thrown out of
gear, the motive force is no longer applied to the axle, and by the aid of
the brakes the engine may be instantly stopped. The movement of the pinions
is effected by two sets of wheels on each of the platforms of the engine,
and near the door for the conductor. By turning one of the wheels to the
right or left on either platform, the conductor imparts either the less or
the greater speed to the engine. In case he has caused the engine to move
forward by turning the second wheel, he will not have to touch it again
until the end of the trip. The brake, which is also operated from the two
platforms, is applied to all four wheels at the same time. From this
arrangement it is seen that the movement is continuous. Nevertheless, the
conductor has access to the regulator by a small chain connected with the
outside by a wheel near at hand, but the action is sufficiently regular not
to require much attention to this feature.


The gas is produced by the Wilford apparatus, which regularly furnishes the
requisite quantity necessary for an explosion, which is produced by a
particular kind of light placed near the piston. The vapor is produced by
passing hot water from the envelope of the cylinder of the motor through
the Wilford apparatus. The water is cooled again in a reservoir (system
Koerting) placed in direct communication with the cylinder. Any permanent
heating is therefore impossible.

The noise of the explosions is prevented by a device invented by Mr.
Stevens himself. It consists of a drum covered with asbestos or any other
material which absorbs noise.

According to the inventor, the saving over the use of horses for traction
is considerable. This system is soon to be tried practically at Antwerp in
Belgium, and then it will be possible to arrive at the actual cost of
traction. - _Industrie Moderne, Brussels_.

* * * * *



The interesting piece of railroad location illustrated in this issue is on
the mountain section of the Western North Carolina Railroad. This section
crosses the Blue Ridge Mountains 18 miles east of Asheville, at a point
known as Swannanoa Gap, 2,660 feet above tide water. The part of the road
shown on the accompanying cut is 10 miles in length and has an elevation of
1,190 feet; to overcome the actual distance by the old State pike was
somewhat over 3 miles. The maximum curvature as first located was 10°, but
for economy of time as well as money this was exceeded in a few instances
as the work progressed, but is now being by degrees reduced. The maximum
grades on tangents are 116 feet per mile; on curves the grade is equated
one-tenth to a degree. The masonry is of the most substantial kind, granite
viaducts and arch culverts. The numbers and lengths of tunnels as indicated
by letters on cut are as follows:

Ft. in all of these.

A. Point Tunnel. 216 ft. long.[1]
B. Jarrett's " 125 " "
C. Lick Log " 562 " "
D. McElroy " 89 " "
E. High Ridge " 415 " "
F. Burgin " 202 " "
G. Swannanoa " 1,800 " "

[Footnote 1: For the sake of economy of space, our cut omits the Point and
Swannanoa tunnels (the latter is the summit tunnel), but covers all of the
location which is of interest to engineers, the remainder at the Swannanoa
end being almost "on tangent" to and through the summit.]

The work was done by the State of North Carolina with convict labor, under
the direction of Mr. Jas. A. Wilson, as president and chief engineer, but
was sold by the State to the Richmond & Danville system. - _Railroad

* * * * *


The new gasholder which has been erected by Messrs. C. and W. Walker for
the Imperial Continental Gas Company at Erdberg, near Vienna, has been
graphically described by Herr E.R. Leonhardt in a paper which he read
before the Austrian Society of Engineers. The enormous dimensions and
elegant construction of the holder - being the largest out of England - as
well as the work of putting up the new gasholder, are of special interest
to English engineers, as Erdberg contains the largest and best appointed
works in Austria. The dimensions of the holder are - inner lift, 195 feet
diameter, 40 feet deep; middle lift, 197½ feet diameter, 40 feet deep;
outer lift, 200 feet diameter, 40 feet deep. The diameter over all is about
230 feet. The impression produced upon the members of the Austrian Society
by their visit to Erdberg was altogether most favorable; and not only did
the inspection of the large gasholder justify every expectation, but the
visitors were convinced that all the buildings were in excellent condition
and well adapted for their purpose, that the machinery was of the latest
and most approved type, and that the management was in experienced hands.


is contained in a building consisting of a circular wall covered with a
wrought iron roof. The holder itself is telescopic, and is capable of
holding 3½ million cubic feet of gas. The accompanying illustrations (Figs.
1 and 3) are a sectional elevation of the holder and its house and a
sectional plan of the roof and holder crown. Having a capacity of close
upon 3,200,000 Austrian cubic feet, this gasholder is the largest of its
kind on the Continent, and is surpassed in size by only a few in England
and America. By way of comparison, Hamburg possesses a holder of 50,000
cubic meters (1,765,000 cubic feet) capacity; and there is one in Berlin
which is expected to hold 75,000 cubic meters (2,647,500 cubic feet) of


The gasholder house at Erdberg is perfectly circular, and has an internal
diameter of 63.410 meters. It is constructed, in three stories, with forty
piers projecting on the outside, and with four rows of windows between the
piers - one in each of the top and bottom stories, and two rows in the
middle. These windows have a height of 1.40 meters in the lowest circle,
where the wall is 1.40 meters thick, and of 2.90 meters in the two top
stories, where it is respectively 1.11 meters and 0.90 meter thick. The top
edge of the wall is 35.35 meters above the base of the building, and 44.39
meters from the bottom of the tank; the piers rising 1.60 meters beyond the
top of the wall. The highest point of the lantern on the roof will thus be
48.95 meters above the ground.


The tank in which the gasholder floats has an internal diameter of 61.57
meters, and therefore a superficial area of 3,000 square meters; and since
the coping is 12.31 meters above the floor, it follows that the tank is
capable of holding 35,500 cubic meters (7,800,000 gallons) of water. The
bottom consists of brickwork 1.10 meters thick, rendered with Portland
cement, and resting on a layer of concrete 1 meter thick. The walls are
likewise of brick and cement, of a thickness of 3.30 meters up to the
ground level, and 2.40 meters thick to the height of 3.44 meters above the
surface. Altogether, 2,988,680 kilos. of cement and 5,570,000 bricks were
used in its construction. In fact, from the bottom of tank to top of roof,
it reaches as high as the monument at London Bridge.


The construction of the tank offered many and serious difficulties. The
bottom of the tank is fully 3 meters below the level of the Danube Canal,
which passes close by, and it was not until twelve large pulsometer pumps
were set up, and worked continually night and day, that it was possible to
reach the necessary depth to allow of the commencement of the foundations
of the boundary wall.


The wrought iron cupola-shaped roof of the gasholder house was designed by
Herr W. Brenner, and consists of 40 radiating rafters, each weighing about
25 cwt., and joined together by 8 polygonal circles of angle iron (90×90×10
mm.). The highest middle circle is uncovered, and carries a round lantern
(Fig. 1). These radiating rafters consist of flat iron bars 7 mm. thick,
and of a height which diminishes gradually, from one interval to another on
the inside, from 252 to 188 mm. At the outside ends (varying from 80×80×9
mm. in the lowest to 60×60×7 mm. in the last polygon but one) these rafters
are strengthened, at least as far as the five lowest ones are concerned, by
flat irons tightly riveted on. At their respective places of support, the
ends of all the spars are screwed on by means of a washer 250 mm. high and
31 mm. thick, and surmounted by a gutter supported by angle irons. From
every junction between the radial rafters and the polygonal circle,
diagonal bars are made to run to the center of the corresponding interval,
where they meet, and are there firmly held together by means of a tongue
ring. The roof is 64.520 meters wide and 14.628 meters high; and its total
weight is 103.300 kilos. for the ironwork - representing a weight of 31.6
kilos. per square meter of surface. It is proposed to employ for its
covering wooden purlins and tin plates. The whole construction has a light,
pleasing, and yet thoroughly solid appearance.


Herr Brenner, the engineer of the Erdberg Works, gives a description of how
the roof of a house, 54.6 meters wide, for a gasholder in Berlin, was
raised to a height of 22 meters. In that instance the iron structure was
put together at the bottom of the tank, leaving the rafter ends and the
mural ring. The hoisting itself was effected by means of levers - one to
each rafter - connected with the ironwork below by means of iron chains. At
the top there were apertures at distances of about 26 mm. from each other,
and through these the hoisting was proceeded with. With every lift, the
iron structure was raised a distance of 26 mm.

[Illustration: FIG. 2.]

Herr Brenner had considerable hesitation in raising in the same way the
structure at Erdberg, which was much larger and heavier than that in
Berlin. The simultaneous elevation to 48 meters above the level, proposed
to be effected at forty different points, did not appear to him to offer
sufficient security. He therefore proposed to put the roof together on the
ground, and to raise it simultaneously with the building of the wall;
stating that this mode would be perfectly safe, and would not involve any
additional cost. The suggestion was adopted, and it was found to possess,
in addition, the important advantage that the structure could be made to
rest on the masonry at any moment; whereas this had been impossible in the
case at the Berlin Gasworks.

[Illustration: FIG. 3.]


At a given signal from the foreman, two operatives, stationed at each of
the forty lifting points, with crowbars inserted in the holes provided for
the purpose, give the screws a simultaneous turn in the same direction. The
bars are then inserted in another hole higher up. The hoisting screws are
connected with the structure of the roof, and rise therewith. All that is
requisite for the hoisting from the next cross beam is to give a forward
turn to the screws. When the workmen had become accustomed to their task,
the hoisting to a distance of 1 meter occupied only about half to
three-quarters of an hour. At the outset, and merely by way of a trial, the
roof was lifted to a height of fully 2 meters, and left for some time
suspended in the air. The eighty men engaged in the operation carry on the
work with great regularity and steadiness, obeying the signal of the
foreman as soon as it was given.


The holder, which was supplied by the well-known firm of Messrs. C. and W.
Walker, of Finsbury Circus, London, and Donnington, Salop, was in an outer
courtyard. It is a three-lift telescopic one; the lowest lift being 200
feet, the middle lift 197 ft. 6 in., and the top lift 195 ft. in diameter.
The height of each lift is 40 feet. The several lifts are raised in the
usual way; and they all work in a circle of 24 vertical U-shaped channel
irons, fixed in the wall of the house by means of 13 supports placed at
equal distances from the base to the summit (as shown in Fig. 2). When the
gasholder is perfectly empty, the three lifts are inclosed, one in the
other, and rest with their lower edges upon the bottom of the tank. In this
case the roof of the top lift rests upon a wooden framework. Fixed in the
floor of the tank are 144 posts, 9 inches thick at the bottom and 6 inches
thick at the top, to support the crown of the holder in such a way that the
tops are fixed in a kind of socket, each of them being provided with four
horizontal bars, which decrease in thickness from 305 by 100 mm. to 150 by
50 mm., and represent 16 parallel polygons, which in their turn are
fastened diagonally by means of iron rails 63 by 100 mm. thick, arranged
crosswise. The top of this framework is perfectly contiguous with the
inside of the crown of the gasholder. The crown itself is made up of iron
plates, the outer rows having a thickness of 11 mm., decreasing to 5 mm.
toward the middle, and to 3 mm. at the top. The plates used for the side
sheets of the holder are: For the top and bottom rows, 6.4 mm.; and for the
other plates, 2.6 mm.

* * * * *

A new bleaching compound has been discovered, consisting of three parts by
measure of mustard-seed oil, four of melted paraffin, three of caustic soda
20° Baume, well mixed to form a soapy compound. Of this one part of weight
and two of pure tallow soap are mixed, and of this mixture one ounce for
each gallon of water is used for the bleaching bath, and one ounce caustic
soda 20° Baume for each gallon is added, when the bath is heated in a close
vessel, the goods entered, and boiled till sufficiently bleached.

* * * * *


[Footnote: A paper by Prof. G.L. Vose, Member of the Boston Society of
Civil Engineers. Read September 15, 1886.]

By Prof. G.L. VOSE.

Few persons, even among those best acquainted with our modern railroad
system, are aware of the early struggles of the men to whose foresight,
energy, and skill the new mode of transportation owes its introduction into
this country. The railroad problem in the United States was quite a
different one from that in Europe. Had we simply copied the railways of
England, we should have ruined the system at the outset, for this country.
In England, where the railroad had its origin, money was plenty, the land
was densely populated, and the demand for rapid and cheap transportation
already existed. A great many short lines connecting the great centers of
industry were required, and for the construction of such in the most
substantial manner the money was easily obtained. In America, on the
contrary, a land of enormous extent, almost entirely undeveloped, but of

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Online LibraryVariousScientific American Supplement, No. 586, March 26, 1887 → online text (page 2 of 10)