the Montigny, Fig. 105_d_. This gun, like the Gatling, is made of
several different sizes, the smallest containing nineteen barrels and
the largest thirty-seven. The barrels are all fitted into a wrought iron
tube, which thus constitutes the compound barrel of the weapon. At the
breech end of this barrel is the movable portion and the mechanism by
which it is worked. The movable portion consists mainly of a short
metallic cylinder of about the same diameter as the compound barrel, and
this is pierced with a number of holes which correspond exactly with the
position of the gun-barrels, of which they would form so many
prolongations. In each of the holes or tubes a steel piston works
freely; and when its front end is made even with the front surface of
the short cylinder, a spiral spring, which is also contained in each of
the tubes, is compressed. The short cylinder moves as a whole backwards
and forwards in the direction of the axis of the piece, the movement
being given by a lever to the shorter arm of which the movable piece is
attached. When the gun is to be loaded this piece is drawn backwards by
raising the lever, when the spiral springs are relieved from
compression, and the heads of the pistons press lightly against a flat
steel plate in front of them. The withdrawal of the breech-block gives
space for a steel plate, bored with holes corresponding to the barrels,
to be slid down vertically; and this plate holds in each hole a
cartridge, the head of each cartridge being, when the plate has dropped
into its position, exactly opposite to the barrel, into which it is
thrust, when the movable breech-block is made to advance. The anterior
face of this breech-block is formed of a plate containing a number of
holes again corresponding to the barrels, and in each hole is a little
short rod of metal, which has in front a projecting point that can be
made to protrude through a _small_ aperture in the front of the plate,
the said small apertures exactly agreeing in position with the centres
of the barrels, and being the only perforations in the front of the
plate. The back of the plate has also openings through which the heads
of the pistons can pass, and by hitting the little pieces, or strikers,
cause their points to pass out through the apertures in front of the
plate, and enter the base of the cartridges, where _fulminate_ is
placed. The plate filled with cartridges has a bevelled edge, and the
points of the strikers are pushed back by it as it descends. The heads
of the pistons are separated until the moment of discharge from the
recesses containing the strikers by the flat steel plate or shutter
already mentioned. The effect, therefore, of pushing the breech-block
forward is to ram the cartridges into the barrels, and at the same time
the spiral springs are compressed, and the heads of the pistons press
against the steel shutter which separates them from the strikers, so
that the whole of the breech mechanism is thus closed up. When the piece
is to be fired a handle is turned, which draws down the steel shutter
and permits the pistons to leap forward one by one, and hit the
strikers, so that the points of the latter enter the cartridges and
inflame the fulminate. The shutter is cut at its upper edge into steps,
so that no two adjoining barrels are fired at once. The whole of the
thirty-seven barrels can be fired by one and a quarter turns of the
handle, which may, of course, be given almost instantly, or, by a slower
movement, the barrels can be discharged at any required rate.
The barrels of the machine guns we have described do not, as is
generally supposed, radiate; on the contrary, they are arranged in a
perfectly parallel direction. In consequence of this, the bullets are at
short ranges directed nearly to one spot. The Gatling gun was adopted as
a service weapon by the British navy, and in several minor actions it
had proved effective, but in its original form it was superseded by the
Gardner gun, in which the barrels are fixed horizontally side by side,
and are in number five or fewer; each barrel is able to fire 120 rounds
per minute. A new system of feed was afterwards applied to the Gatling
gun by Mr. Accles, by means of which this gun was greatly improved and
its rate of firing was increased to more than 1,000 rounds per minute;
indeed, 80 rounds have been fired from it within 2 seconds. The Gatlings
in this improved form have ten barrels, and are provided with feed
drums, each containing 104 cartridges, and capable, when empty, of being
almost instantly replaced by a full one. The contents of one drum can,
if necessary, be discharged in about 2¼ seconds, so that in this time
104 rifle bullets would be fired; or considerably more than the rate of
1,000 rounds per minute could easily be maintained. The weapon is so
mounted, that without moving its carriage it can be pointed at any angle
of elevation or depression, and through a considerable lateral range.
Mr. Nordenfelt has brought out a machine gun, which, on account of the
simplicity and strength of its firing mechanism, has proved the most
reliable weapon of its class, and it also has been adopted into the
British service, and indeed into that of nearly every nation in the
world. In this gun there are five barrels arranged as in the Gardner,
but the firing is operated by a lever working backwards and forwards at
the rate of 600 rounds per minute.
[Illustration:
FIG. 105_e_.—_A Hotchkiss Gun._
]
In the firing of all these weapons, by turning a crank, or moving a
lever at one side, any attempt at exact aiming must obviously be
difficult if not impossible, from the liability of the gun to get moved.
Several designs have been proposed for making the firing mechanism
entirely automatic so as to require no effort on the part of the firer,
whose attention can then be directed solely to pointing the piece. It
would not be easy to explain in detail the way in which this is
accomplished in these very ingenious guns; for while the principle of
their action is sufficiently clear, namely, that the force of the recoil
is made to extract the spent cartridge, open the breech, insert a fresh
cartridge, close the breech, and fire the charge, the mechanism of the
reacting springs, etc., by which this is effected could scarcely, even
by the aid of elaborate diagrams, be made intelligible to any other than
a gunsmith. The Maxim is one of those automatic guns: it has but one
barrel, and after the first discharge it will go on firing with
marvellous rapidity the cartridges supplied to it in a continuous chain,
and this without any deviation from such direction as may be given to it
by the operator, for he has neither crank to turn nor lever to move, but
merely sits behind an iron shield directing the weapon at will, which,
without interference, fires hundreds of shots per minute from one
barrel, so long as the long bands of cartridges are supplied to it.
Mr. Nordenfelt and Mr. Hotchkiss have also both contrived quick firing
guns for 1–lb., 3–lb., and 6–lb. projectiles, and these, it has been
thought, will be of great service in naval warfare as against torpedo
boats.
Though the automatic mechanism, whereby the breech operations are all
performed by the force of the recoil of the barrel, which is allowed to
slide backwards, and is then returned to its place by a spring, is too
complicated for illustration here, mention may be made of a quite recent
device by which the recoil action is dispensed with, and the mechanism
so far simplified that scarcely more than half the number of parts in
the lock mechanism are required. Imagine a closed tube beneath the
barrel, parallel to it, and communicating with it only by a small boring
near the muzzle; through this opening the expanding gases will pass, in
a degree depending on its size and position, and by their action on a
piston near the breech, impulses are supplied that will actuate the lock
mechanism so long as cartridges are supplied, as they may be in a
continuous band. A weapon of this construction has been already tried,
and its discharges are so rapid that the sound of them is described as
being quite deafening. This plan appears to be equally applicable to
small arms, and to machine or field guns. A very effective gun of the
kind, which fires ordinary rifle bullets, has been contrived by Mr.
Hotchkiss, and is represented in Fig. 105_e_. It is capable of sending
forth as many as 1,000 shots in one minute.
Modern ordnance has required certain modifications in the making of
gunpowder, so that the original name of _powder_ would now hardly be
applicable at all. The large charges now used, if introduced in the form
of fine powder, would certainly shatter the guns from the suddenness of
the exploding force. Hence the material is made up into larger or
smaller masses, generally rounded like small pebbles. The explosive used
for the huge 110–ton guns presents itself in the form of
chocolate-coloured hexagonal prisms, two or three inches long and about
an inch in diameter. These are obtained by compressing the specially
prepared material into moulds with a hydraulic press. The reason for
this process is that, in order to obtain precision and uniformity in the
effects, not only must the composition of the powder be always the same,
but the size, shape, weight, and number of the several portions that
make up the charge must be invariable. It has not been found possible to
fire one of these monster guns many times without such signs of
deterioration as would suggest a short “life” for each of them. But the
greatest necessity for modern fire-arms is a smokeless powder or other
explosive. It is obvious that the advantages of quick firing, whether of
large or of small fire-arms, are greatly reduced if the soldier or
gunner is prevented by smoke from taking aim. The invention of a
smokeless gunpowder has several times been announced, and great advances
have, indeed, been made towards its realization. Certain compositions,
which appeared to meet the requirement of being practically smokeless,
have, however, been found liable to chemical changes, or to corrode the
bore, or to possess other objectionable properties. In this country the
explosive coming into use as best adapted for quick firing guns, etc.,
presents itself in appearance like whitish or grey strings, and has
hence received the name of _cordite_. The composition and mode of
manufacture of these new substitutes for gunpowder are not readily
disclosed, each military authority jealously guarding its own secrets.
The problem of smokeless powder has, however, been almost completely
solved, for at a military review that took place on the Continent in
1889, the discharge of the rifles (loaded with blank cartridges, of
course) is said to have been attended with no more smoke than the puff
of a cigar. The new invention will cause some changes in military
tactics, for the manœuvres formerly executed under cover of the battle
smoke will no longer be possible. Some particulars as to the nature of
smokeless powders will be found in the article on “Explosives.”
[Illustration]
[Illustration:
FIG. 106.—_Harvey’s Torpedo. Working the Brakes._
]
TORPEDOES.
The notion of destroying ships or other structures by explosions of
gunpowder, contained in vessels made to float on the surface of the
water, or submerged beneath it, is not of very modern origin. Two
hundred and fifty years ago the English tried “floating petards” at the
siege of Rochelle. During the American War of Independence similar
contrivances were used against the British, and from time to time since
then “torpedoes,” as they were first termed by Fulton, have been
employed in warfare in various forms; but up to quite a recent period
the use of torpedoes does not appear to have been attended with any
decided success, and it is probable that but for the deplorable Civil
War in the United States we should have heard little of this invention.
During that bitter fratricidal struggle, however, when so much ingenuity
was displayed in the contrivance of subsidiary means of attack and
defence, the torpedo came prominently into notice, having been employed
by the Confederates with the most marked effects. It is said that
thirty-nine Federal ships were blown up by Confederate torpedoes, and
the official reports own to twenty-five having been so destroyed. This
caused the American Government to turn their attention to the torpedo,
and they became so convinced of the importance of this class of war
engine that they built boats expressly for torpedo warfare, and equipped
six _Monitors_ for the same purpose.
It has been well remarked that the torpedo plays the same part in naval
warfare as does the mine in operations by land. This exactly describes
the purpose of the torpedo where it is used defensively, but the
comparison fails to suggest its capabilities as a weapon of offence.
There are few occasions where a mine is made the means of attack, while
the torpedo readily admits of such an employment, and, used in this way,
it may become a conspicuous feature of future naval engagements. Many
forms of this war engine have been invented, but all may be classified,
in the first place, under two heads: viz., stationary torpedoes, and
mobile or offensive torpedoes; while independent distinctions may be
made according to the manner of firing the charge; or, again, according
to the mode of determining the instant of the explosion. The stationary
torpedo may be fixed to a pile or a raft, or attached to a weight; the
offensive torpedo may be either allowed to float or drift against the
hostile ships, or it may be propelled by machinery, or attached to a
spar of an ironclad or other vessel. The charge may be fired by a match,
by percussion, by friction, by electricity, or by some contrivance for
bringing chemicals into contact which act strongly upon each other, and
thus generate sufficient heat to ignite the charge. The instant of
explosion may be determined by the contact of the torpedo with the
hostile structure (in which case it is said to be “self-acting”), or by
clockwork, or at the will of persons directing the operations. In some
cases lines attached to triggers are employed; in others electric
currents are made use of.
[Illustration:
FIG. 107.—_Submerged Torpedo._
]
In the American Civil War the stationary torpedoes at first laid down
were self-acting, that is, they were so arranged as to explode when
touched by a passing vessel. Such arrangements present the great
disadvantages of being as dangerous to friendly as to hostile ships. The
operation of placing them is a perilous one, and when once sunk, they
can only be removed at great risk. Besides this, they cannot be relied
on for certain action in time of need, as the self-acting apparatus is
liable to get out of order. The superiority of the method of firing them
from the shore when the proper instant arrived, became so obvious that
the self-acting torpedo was soon to a great extent superseded by one so
arranged that an observer could fire it at will, by means of a
trigger-line or an electric current. Similar plans had often been
previously employed or suggested. For example, during the war between
Austria and Italy the Austrian engineers at Venice had very large
electric torpedoes sunk in the channels which form the approaches to the
city. They consisted of large wooden cases capable of containing 400
lbs. of gun-cotton, moored by chains to a wooden framework, to which
weights were lashed that sufficed to sink the whole apparatus, Fig. 107.
A cable containing insulated wires connected the torpedo with an
electrical arrangement on shore, and the explosion could take place only
by the operator sending a current through these wires. The torpedo was
wholly submerged, so that there was nothing visible to distinguish its
position. There was no need of a buoy or other mark, as in the case of
self-acting torpedoes, to warn friendly vessels off the dangerous spot,
and therefore nothing appeared to excite an enemy’s suspicions. But it
is, however, absolutely necessary that the defenders should know the
precise position of each of their submarine mines, so that they might
explode it at the moment the enemy’s ship came within the range of its
destructive action. This was accomplished at Venice in a highly
ingenious manner, by erecting a camera obscura in such a position that a
complete picture of the protected channels was projected on a fixed
white table. While the torpedoes were being placed in their positions an
observer was stationed at the table, who marked with a pencil the exact
spot at which each torpedo was sunk into the water. Further, those
engaged in placing the torpedoes caused a small boat to be rowed round
the spot where the torpedo had been placed, so as to describe a circle
the radius of which corresponded to the limit of the effective action of
the torpedo. The course of the boat was traced on the picture in the
camera, so that a very accurate representation of the positions of the
submarine mines in the channels was obtained. Each circle traced on the
table was marked by a number, and the wire in connection with the
corresponding torpedo was led into the camera, and marked with the same
number, so that the observer stationed in the camera could, when he saw
the image of an enemy’s ship enter one of the circles, close the
electric circuit of the corresponding wire, and thus instantly explode
the proper torpedo. The events of the war did not afford an opportunity
of testing practically the efficiency of these preparations.
Another mode of exploding torpedoes from the shore has been devised by
Abel and Maury. It has the advantage of being applicable by night as
well as by day. The principle will be easily understood with the
assistance of the diagram, Fig. 108, in which, for the sake of
simplicity, the positions of only three torpedoes, 1, 2, 3, are
represented.
[Illustration:
FIG. 108.—_Mode of Firing Torpedo._
]
In this arrangement two observers are required at different stations on
the shore. At each station—which should not, of course, be in any
conspicuous position—is a telescope, provided with a cross-wire, and
capable of turning horizontally about an upright axis. The telescope
carries round with it, over a circular table of non-conducting
substance, a metallic pointer which presses against narrow slips of
metal let into the circumference of the table. To each slip of metal a
wire passing to a torpedo is attached, and another wire is connected
with the axis of the pointer, so as to be put into electric contact with
each of the others when the pointer touches the corresponding piece of
metal on the rim of the table. The mode in which these wires are
connected with the torpedoes, the telescopes, and the electric apparatus
is shown by the lines in the diagram. At each station is a key, which
interrupts the electric circuit except when it is pressed down by the
operator. There are thus four different points at which contacts must be
simultaneously made before the circuit can be complete or a torpedo
explode. In the diagram three of these are represented as closed, and in
such a condition of affairs it only remains for the observer to depress
the handle of the key at station B to effect the explosion of torpedo
No. 2. The observer at station a is supposed to see the approaching
vessel in the line of torpedo No. 2, and recognizing this as an enemy’s
ship, he depresses the key at his station. The operator at B, by
following the course of the vessel with his telescope, will have brought
the pointer into contact with the wire leading to No. 2 torpedo, and he
then causes the explosion to take place by completing the circuit by
depressing his key. A modification of this plan is proposed by which the
position of the torpedoes is indicated by placing marks, such as
differently-coloured flags, or by night lamps with coloured glasses,
throwing their light only towards the telescopes. These marks are placed
in the line of direction of each torpedo from the telescope as at
_c_{1}_, _c_{2}_, _c_{3}_ and _b_{1}_, _b_{2 3}_; and if they can be put
at some distance, the position of the torpedo is determined with great
accuracy by the intersection of the lines of sight of the two
telescopes. Electric wires connect the stations and the torpedoes in the
same manner as we have before described. Such methods of firing
torpedoes are no doubt the most efficient, for the destructive charge
may be sunk so far below the surface that not a ripple or an eddy can
excite an enemy’s suspicion, or the channel appear otherwise than free
and unobstructed, while friendly ships may pass and repass without risk;
for the current which determines the explosion only passes when the two
sentinels complete the circuit by simultaneously depressing their keys.
Attempts have often been made to convert the torpedo into an offensive
weapon, by causing vessels containing explosive charges to drift by
currents, or otherwise, into contact with the enemy’s ships. The results
have been always unsatisfactory, as there is great uncertainty of the
machine coming into contact with its intended mark. Besides, it is easy
to defend vessels against such attacks by placing nets, &c., to
intercept the hostile visitors, especially if the attack is made by day,
and by night the chance that a torpedo drifting at random would strike
its object is very small indeed. One condition essential to the success
of such attacks is that the approach of the insidious antagonist may be
unobserved. Accordingly divers schemes have been projected for
propelling vessels wholly submerged beneath the surface of the water, so
that they may approach their object unperceived, and exert their
destructive effect precisely at that part of the vessel where damage is
most fatal, and where an ironclad vessel is most vulnerable, namely,
below the water-line. Vessels have been built, propelled by steam and so
contrived that their bodies are wholly submerged, only the funnel being
visible above the surface. These _quasi_ submarine ships carry small
crews, and are fitted with a long projecting spar in front, at the end
of which is carried the torpedo.
[Illustration:
FIG. 109.—_Explosion of Whitehead’s Torpedo._
]
[Illustration:
FIG. 110.—_Effect of the Explosion of Whitehead’s Torpedo._
]