may be seen no more; in a few years the bayonet may be relegated to
the limbo of the coat-of-mail or the cast-iron culverin. Yet the
modern battle-scene bristles with the most death-dealing weapons which
the ingenuity of man has ever constructed. The hand-drawn machine-gun
discharges in a couple of minutes as many missiles as a regiment of
Wellington’s infantry, with a speed and precision undreamt of by him.
The quick-firing long-range naval guns now in vogue could annihilate a
fleet or destroy a port without approaching close enough to catch a
glimpse of the personnel of their opponents. The deadly torpedo guards
our waterways more effectually than a squadron of ships.
All resources of civilisation have been drawn upon, every triumph of
engineering secured, to forge such weapons as shall strike the hardest
and destroy the most pitilessly. But strange and unexpected the
result! Where we counted our battle-slain by thousands we now mourn
over the death of hundreds; where whole regiments were mown down our
ambulances gather wounded in scattered units. Here is the bright side
of modern war.
The muzzle-loading gun has had its day, a very long day and a
successful one. Again and again it has reasserted itself and ousted
its rivals, but at last all difficulties of construction have been
surmounted and the breech-loader has “come to stay.”
However, our services still contain a large number of muzzle-loading
guns, many of them built at quite a recent period, and adapted as far
as possible to modern requirements. So to these we will first turn our
attention.
The earliest guns were made of cast-iron, but this being prone to
burst with a large charge, bronze, brass, and other tougher materials
were for a long time employed. Most elaborately chased and ornamented
specimens of these old weapons are to be seen in the Tower, and many
other collections.
In the utilitarian days of the past century cheapness and speed in
manufacture were more sought after than show. Iron was worked in many
new ways to resist the pressure of explosion.
Armstrong of Elswick conceived the idea of building up a barrel of
_coiled_ iron by joining a series of short welded cylinders together,
and closing them by a solid forged breech-piece. Over all, again,
wrought-iron coils were shrunk. Subsequently he tried a solid
forged-iron barrel bored out to form a tube. Neither make proving very
satisfactory, steel tubes were next used, but were too expensive and
uncertain at that stage of manufacture. Again coiled iron was called
into requisition, and Mr. Frazer of the Royal Gun Factory introduced a
system of double and triple coils which was found very successful,
especially when a thin steel inner tube was substituted for the iron
one (1869).
All these weapons were rifled, so that there was of necessity a
corresponding difference in the projectile employed. Conical shells
being used, studs were now placed on the body of the shell to fit into
the rifling grooves, which were made few in number and deeply cut.
This was apt to weaken the bore of the gun; but on the other hand
many studs to fit into several shallow grooves weakened the cover of
the shells.
Various modifications were tried, and finally a gas-check which
expands into the grooves was placed at the base of the shell.
The muzzle-loader having thus been turned into a very efficient modern
weapon the next problem to be solved was how to throw a projectile
with sufficient force to penetrate the iron and steel armour-plates
then being generally applied to war-ships. “Build larger guns” was the
conclusion arrived at, and presently the arsenals of the Powers were
turning out mammoth weapons up to 100 tons, and even 110 tons in
weight with a calibre of 16 inches and more for their huge shells.
Then was the mighty 35-ton “Woolwich Infant” born (1872), and its
younger but still bigger brothers, 81 tons, 16-inch bore, followed by
the Elswick 100-ton giants, some of which were mounted on our defences
in the Mediterranean. But the fearful concussion of such enormous guns
when fixed in action on board ship injured the superstruction, and
even destroyed the boats, and the great improvements made in steel
both for guns and armour soon led to a fresh revolution. Henceforward
instead of mounting a few very heavy guns we have preferred to trust
to the weight of metal projected by an increased number of smaller
size, but much higher velocity. And these guns are the quick-firing
breech-loaders.
The heaviest of our up-to-date ordnance is of moderate calibre, the
largest breech-loaders being 12-inch, 10-inch, and 9.2-inch guns. But
the elaborateness of its manufacture is such that one big gun takes
nearly as long to “build up” as the ship for which it is destined.
Each weapon has to pass through about sixteen different processes:--
(1) The solid (or hollow) ingot is _forged_.
(2) _Annealed_, to get rid of strains.
(3) It is placed horizontally on a lathe and _rough-turned_.
(4) _Rough-bored_ in a lathe.
(5) _Hardened._ Heated to a high temperature and plunged, while
hot, into a bath of rape oil kept cold by a water-bath. It
cools slowly for seven to eight hours, being moved about at
intervals by a crane. This makes the steel more elastic and
tenacious.
(6) _Annealed_, _i.e._ reheated to 900° Fahr. and slowly
cooled. Siemens’ pyrometer is used in these operations.
(7) _Tested_ by pieces cut off.
(8) _Turned_ and _bored_ for the second time.
(9) Carefully turned again for _shrinkage_. Outer coil expanded
till large enough to fit easily over inner. Inside, set up
vertically in a pit, has outside lowered on to it, water and
gas being applied to make all shrink evenly. Other projections,
hoops, rings, &c., also shrunk on.
(10) Finish--_bored_ and _chambered_.
(11) _Broached_, or very fine bored, perhaps _lapped_ with lead
and emery.
(12) _Rifled_ horizontally in a machine.
(13) Prepared for breech fittings.
(14) Taken to the Proof Butts for trial.
(15) Drilled for sockets, sights, &c. Lined and engraved.
Breech fittings, locks, electric firing gear, &c., added. Small
adjustments made by filing.
(16) _Browned_ or _painted_.
When worn the bore can be lined with a new steel tube.
These lengthy operations completed, our gun has still to be _mounted_
upon its field-carriage, naval cone, or disappearing mounting, any of
which are complicated and delicately-adjusted pieces of mechanism, the
product of much time and labour, which we have no space here to
describe.
Some account of the principal parts of these guns has already been
given, but the method by which the breech is closed remains to be
dealt with.
It will be noticed that though guns now barely reach half the weight
of the monster muzzle-loaders, they are even more effective. Thus the
46-ton (12-inch) gun hurls an 850-lb. projectile with a velocity of
2750 foot-seconds, and uses a comparatively small charge. The famous
“81-ton” needed a very big charge for its 1700-lb. shell, and had
little more than half the velocity and no such power of penetration.
This change has been brought about by using a slower-burning explosive
very powerful in its effects; enlarging the chamber to give it
sufficient air space, and lengthening the chase of the gun so that
every particle of the powder-gas may be brought into action before
the shot leaves the muzzle. This system and the substitution of steel
for the many layers of welded iron, makes our modern guns long and
slim in comparison with the older ones.
To resist the pressure of the explosion against the breech end, a
tightly-fitting breech-plug must be employed. The most modern and
ingenious is the Welin plug, invented by a Swedish engineer. The
ordinary interrupted screw breech-plug has three parts of its
circumference plane and the other three parts “threaded,” or grooved,
to screw into corresponding grooves in the breech; thus only half of
the circumference is engaged by the screw. Mr. Welin has cut steps on
the plug, three of which would be threaded to one plane segment, each
locking with its counterpart in the breech. In this case there are
three segments engaged to each one left plane, and the strength of the
screw is almost irresistible. The plug, which is hinged at the side,
has therefore been shortened by one-third, and is light enough to
swing clear with one touch of the handwheel that first rotates and
unlocks it.
The method of firing is this: The projectile lifted (by hydraulic
power on a ship) into the loading tray is swung to the mouth of the
breech and pushed into the bore. A driving-band attached near its base
is so notched at the edges that it jams the shell closely and prevents
it slipping back if loaded at a high angle of elevation. The powder
charge being placed in the chamber the breech-plug is now swung-to and
turned till it locks close. The vent-axial or inner part of this
breech-plug (next to the charge), which is called from its shape the
“mushroom-head,” encloses between its head and the screw-plug the de
Bange obturator, a flat canvas pad of many layers soaked with mutton
fat tightly packed between discs of tin. When the charge explodes, the
mushroom-head--forced back upon the pad--compresses it till its edges
bulge against the tube and prevent any escape of gas breechwards.
The electric spark which fires the charge is passed in from outside by
means of a minute and ingenious apparatus fitted into a little vent or
tube in the mushroom-head. As the electric circuit cannot be completed
till the breech-plug is screwed quite home there is now no more fear
of a premature explosion than of double loading. If the electric gear
is disordered the gun can be fired equally well and safely by a
percussion tube.
This description is of a typical large gun, and may be applied to all
calibres and also to the larger quick-firers. The mechanism as the
breech is swung open again withdraws the empty cartridge. So valuable
has de Bange’s obturator proved, however, that guns up to the 6-inch
calibre now have the powder charge thrown into the chamber in bags,
thus saving the weight of the metal tubes hitherto necessary.
Of course several types of breech-loading guns are used in the
Service, but the above are the most modern.
The favourite mode of construction at the present time is the
wire-wound barrel, the building up of which is completed by covering
the many layers of wire with an outer tube or jacket expanded by heat
before it is slipped on in order that it may fit closely when cold. A
previous make, without wire, is strengthened by rings or hoops also
shrunk on hot.
The quick-firers proper are of many sizes, 8-inch, 7.5-inch, 6-inch,
4.7-inch, 4-inch, and 3-inch (12-pounders). The naval type is as a
rule longer and lighter than those made for the rough usage of field
campaigning and have a much greater range. There are also smaller
quick-firers, 3-pounders and 6-pounders with bore something over
1-inch and 2-inch (Nordenfelt, Hotchkiss, Vickers-Maxim). Some of the
high velocity 12-pounders being employed as garrison guns along with
6-inch and 4.7-inch, and the large calibre howitzers.
We still use howitzer batteries of 5-inch bore in the field and in the
siege-train, all being short, rifled, breech-loading weapons, as they
throw a heavy shell with smallish charges at a high angle of
elevation, but cover a relatively short distance. A new pattern of
8-inch calibre is now under consideration.
It is interesting to contrast the potencies of some of these guns, all
of which use cordite charges.
+----------+---------------+-----------+----------------+-----------+
|Calibre. | Charge. |Weight of |Muzzle Velocity |Number of |
| | | Shot. | in |Rounds per |
| | | | Foot Seconds. | Minute. |
+----------+---------------+-----------+----------------+-----------+
| 12 inch |207 lbs. | 850 lbs. | 2750 | 1 |
| 8 ” | 52 ” | 210 ” | 2750 | 5 |
| 6 ” | 25 ” | 100 ” | 2775 | 8 |
|4.7 ” | 9 ” | 45 ” | 2600 | 12 |
| 3 ” | 2 lbs. 9 oz. |12.5 ” | 2600 | 20 |
+----------+---------------+-----------+----------------+-----------+
[Illustration: _The Simms armour-clad motor-car for coast defence.
Maxim guns and Pom-pom in action._]
In the armament of our fine Navy guns are roughly distributed as
follows:--81-ton, 13-1/2-inch, and superseded patterns of machine-guns
such as Gatling’s, Gardner’s, and Nordenfelt’s, besides a few
surviving muzzle-loaders, &c., are carried only by the oldest
battleships.
The first-class battleships are chiefly supplied with four 12-inch
guns in barbettes, twelve 6-inch as secondary batteries, and a number
of smaller quick-firers on the upper decks and in the fighting tops,
also for use in the boats, to which are added several Maxims.
The first-class cruisers have 9.2 as their largest calibre, with a
lessened proportion of 6-inch, &c. Some of the newest bear only 7-1/2
or 6-inch guns as their heaviest ordnance; like the second-class
cruisers which, however, add several 4.7‘s between these and their
small quick-firers.
Vessels of inferior size usually carry nothing more powerful than the
4.7.
All are now armed with torpedo tubes.
These same useful little quick-firers and machine-guns have been the
lethal weapons which made the armoured trains so formidable. Indeed,
there seems no limit to their value both for offence and defence, for
the battle chariot of the ancient Briton has its modern successor in
the Simms’ motor war car lately exhibited at the Crystal Palace. This
armour-plated movable fort is intended primarily for coast defence,
but can work off beaten tracks over almost any sort of country. It is
propelled at the rate of nine miles an hour by a 16-horse-power
motor, carrying all its own fuel, two pom-poms, two small Maxims, and
10,000 rounds of ammunition, besides the necessary complement of men
and searchlights for night use, &c., &c.
The searchlight, by the way, has taken the place of all former
inventions thrown from guns, such as ground-light balls, or parachute
lights with a time-fuse which burst in the air and remained suspended,
betraying the enemy’s proceedings.
In like manner the linked chain and “double-headed” shot, the
“canister”--iron balls packed in thin iron or tin cylinders which
would travel about 350 yards--the “carcasses” filled with inflammable
composition for firing ships and villages, are as much out of date as
the solid round shot or cannon-ball. Young Shrapnell’s invention a
century ago of the form of shell that bears his name, a number of
balls arranged in a case containing also a small bursting-charge fired
either by percussion or by a time-fuse, has practically replaced them
all. Thrown with great precision of aim its effective range is now up
to 5000 yards. A 15-pounder shrapnell shell, for instance, contains
192 bullets, and covers several hundred yards with the scattered
missiles flying with extreme velocity.
Common shell, from 2-1/2 to 3 calibres long, contains an explosive
only. Another variety is segment shell, made of pieces built up in a
ring with a bursting charge in the centre which presently shatters
it.
The Palliser shell has a marvellous penetrating power when used
against iron plates. But, _mirabile dictu!_ experiments tried within
the past few months prove that a soft cap added externally enables a
projectile to pierce with ease armour which had previously defied
every attack.
EXPLOSIVES.
Half a century ago gunpowder was still the one driving power which
started the projectile on its flight. It is composed of some 75 parts
of saltpetre or nitrate of potash, 15 parts of carefully prepared
charcoal, and 10 parts of sulphur. This composition imprisons a large
amount of oxygen for combustion and is found to act most successfully
when formed into rather large prismatic grains.
On the abolition of the old flint-lock its place was taken by a
detonating substance enclosed in a copper cap, and some time later
inventors came forward with new and more powerful explosives to
supersede the use of gunpowder.
By treating cotton with nitric and sulphuric acid reaction
_gun-cotton_ was produced; and a year later glycerine treated in the
same manner became known to commerce as _nitro-glycerine_. This liquid
form being inconvenient to handle, some inert granular substance such
as infusorial earth was used to absorb the nitro-glycerine, and
_dynamite_ was the result.
The explosion of gun-cotton was found to be too sudden and rapid for
rifles or cannon; it was liable to burst the piece instead of blowing
out the charge. In order to lessen the rapidity of its ignition
ordinary cotton was mixed with it, or its threads were twisted round
some inert substance.
When repeating-rifles and machine-guns came into general use a
smokeless powder became necessary. Such powders as a rule contain
nitro-cellulose (gun-cotton) or nitro-glycerine, or both. These are
combined into a plastic, gluey composition, which is then made up into
sticks or pellets of various shapes, and usually of large size to
lessen the extreme rapidity of their combustion. Substances such as
tan, paraffin, starch, bran, peat, &c., &c., and many mineral salts,
are used in forming low explosives from high ones.
To secure complete combustion some of the larger pellets are made with
a central hole, or even pierced by many holes, so that the fire
penetrates the entire mass and carries off all its explosive
qualities.
Our _cordite_ consists of nitro-glycerine dissolving di-nitro
cellulose by the acid of a volatile solvent and a mineral jelly or
oil. This compound is semi-fluid, and being passed like macaroni
through round holes in a metal plate it forms strings or cords of
varying size according to the diameter of the holes. Hence the name,
cordite.
Many experiments in search of more powerful explosives resulted in an
almost universal adoption of picric acid as the base. This acid is
itself produced by the action of nitric acid upon carbolic acid, and
each nation has its own fashion of preparing it for artillery.
The French began with _mélinite_ in 1885, this being a mixture of
picric acid and gun-cotton.
The composition of _lyddite_ (named from its place of manufacture,
Lydd, in Kent) is a jealously-guarded British secret. This substance
was first used in 5-inch howitzers during the late Soudan campaign,
playing a part in the bombardment of Omdurman. The effect of the
50-lb. lyddite shells upon the South African kopjes is described as
astounding. When the yellow cloud had cleared away trees were seen
uprooted, rocks pulverised, the very face of the earth had changed.
Several attempts have been made to utilise dynamite for shells, some
of the guns employing compressed air as their motive power. The United
States some years ago went to great expense in setting up for this
purpose heavy pneumatic plant, which has recently been disposed of as
too cumbrous. Dudley’s “Aërial Torpedo” gun discharged a 13-lb. shell
containing explosive gelatine, gun-cotton, and fulminate of mercury by
igniting the small cordite charge in a parallel tube, through a vent
in which the partially cooled gases acted on the projectile in the
barrel. This was rotated in the air by inclined blades on a tailpiece,
as the barrel could not be rifled for fear of the heat set up by
friction. Some guns actuated on much the same principle are said to
have been used with effect in the Hispano-American war. Mr. Hudson
Maxim with his explosive “maximite” claims to throw half a ton of
dynamite about a mile, and a one-ton shell to half that distance.
But even these inventors are outstripped by Professor Birkeland, who
undertakes to hurl a projectile weighing two tons from an iron tube
coiled with copper wire down which an electric current is passed; thus
doing away entirely with the need of a firing-charge.
IN THE GUN FACTORY.
Let us pay a visit to one of our gun factories and get some idea of
the multiform activities necessary to the turning out complete of a
single piece of ordnance or a complicated machine-gun. We enter the
enormous workshop, glazed as to roof and sides, full of the varied
buzz and whirr and clank of the machinery. Up and down the long bays
stand row upon row of lathes, turning, milling, polishing, boring,
rifling--all moving automatically, and with a precision which leaves
nothing to be desired. The silent attendants seem to have nothing in
their own hands, they simply watch that the cutting does not go too
far, and with a touch of the guiding handles regulate the pace or
occasionally insert a fresh tool. The bits used in these processes are
self-cleaning, so the machinery is never clogged; and on the ground
lie little heaps of brass chips cut away by the minute milling tools;
or in other places it is bestrewn with shavings of brass and steel
which great chisels peel off as easily as a carpenter shaves a deal
board.
Here an enormous steel ingot, forged solid, heated again and again in
a huge furnace and beaten by steam-hammers, or pressed by hydraulic
power between each heating till it is brought to the desired size and
shape, is having its centre bored through by a special drill which
takes out a solid core. This operation is termed “trepanning,” and is
applied to guns not exceeding eight inches; those of larger calibre
being rough-bored on a lathe, and mandrils placed in them during the
subsequent forgings. The tremendous heat generated during the boring
processes--we may recall how Benjamin Thompson made water boil by the
experimental boring of a cannon--is kept down by streams of soapy
water continually pumped through and over the metal. We notice this
flow of lubricating fluid in all directions, from oil dropping slowly
on to the small brass-milling machines to this fountain-play of water
which makes a pleasant undertone amidst the jangle of the machines.
But these machines are less noisy than we anticipated; in their actual
working they emit scarcely the slightest sound. What strikes us more
than the supreme exactness with which each does its portion of the
work, is the great deliberateness of its proceeding. All the hurry and
bustle is above us, caused by the driving-bands from the engine, which
keeps the whole machinery of the shed in motion. Suddenly, with harsh
creakings, a great overhead crane comes jarring along the bay, drops a
chain, grips up a gun-barrel, and, handling this mass of many tons’
weight as easily as we should lift a walking-stick, swings it off to
undergo another process of manufacture.
We pass on to the next lathe where a still larger forging is being
turned externally, supported on specially devised running gear, many
different cutters acting upon it at the same time, so that it is
gradually assuming the tapering, banded appearance familiar to us in
the completed state.
We turn, fairly bewildered, from one stage of manufacture to another.
Here is a gun whose bore is being “chambered” to the size necessary
for containing the firing charge. Further along we examine a more
finished weapon in process of preparation to receive the breech-plug
and other fittings. Still another we notice which has been
“fine-bored” to a beautifully smooth surface but is being improved yet
more by “lapping” with lead and emery powder.
In the next shed a marvellous machine is rifling the interior of a
barrel with a dexterity absolutely uncanny, for the tool which does
the rifling has to be rotated in order to give the proper “twist” at
the same moment as it is advancing lengthwise down the bore. The
grooves are not made simultaneously but as a rule one at a time, the
distance between them being kept by measurements on a prepared disc.
Now we have reached the apparatus for the wire-wound guns, a principle
representing the _ne plus ultra_ of strength and durability hitherto
evolved. The rough-bored gun is placed upon a lathe which revolves
slowly, drawing on to it from a reel mounted at one side a continuous
layer of steel ribbon about a quarter of an inch wide. On a 12-inch
gun there is wound some 117 miles of this wire! fourteen layers of it
at the muzzle end and seventy-five at the breech end. Heavy weights
regulate the tension of the wire, which varies for each layer, the
outermost being at the lowest tension, which will resist a pressure of
over 100 tons to the square inch.