The Romance of Modern Invention Part 6

The modern long-range guns and improved howitzers have, however, virtually superseded mortars. _Machine-guns_ of various forms are comparatively small and light, transportable by hand, and filling a place between cannon and small-arms, the latter term embracing the soldier's personal armament of rifle and pistol or revolver, which are carried in the hand.

A group of guns of the like design are generally given the name of their first inventor, or the place of manufacture: such as the Armstrong gun, the Vickers-Maxim, the Martini-Henry rifle, or the Enfield.

The indifferent use of several expressions in describing the same weapon is, however, rather confusing. One particular gun may be thus referred to:--by its _weight_ in tons or cwt., as "the 35-ton gun"; by the weight of its _projectile_, as "a 68-pounder"; by its _calibre_, that is, size of bore, as "the 4-inch gun." Of these the heavier breech-loading (B.-L.) and quick-firing (Q.-F.) guns are generally known by the size of bore; small Q.-F.'s, field-guns, &c., by the weight of projectile. It is therefore desirable to enter these particulars together when making any list of service ordnance for future reference.

No individual gun, whether large or small, is a single whole, but consists of several pieces fastened together by many clever devices.

The princ.i.p.al parts of a cannon are:--

(1) The _chase_, or main tube into which the projectile is loaded; terminating at one end in the muzzle.

(2) The _breech-piece_, consisting of (_a_) the chamber, which is bored out for a larger diameter than the chase to contain the firing-charge. (_b_) The _breech-plug_, which is closed before the charge is exploded and screwed tightly into place, sealing every aperture by means of a special device called the "obturator," in order to prevent any gases pa.s.sing out round it instead of helping to force the projectile forwards towards the muzzle.

The whole length of inside tube is termed the _barrel_, as in a machine-gun, rifle, or sporting-piece, but in the two latter weapons the breech-opening is closed by sliding or springing back the breech-block or bolt into firing position.

Old weapons as a rule were smooth-bored (S.-B.), firing a round missile between which and the barrel a considerable amount of the gases generated by the explosion escaped and caused loss of power, this escape of gas being known as _windage_.

In all modern weapons we use conical projectiles, fitted near the base with a soft copper driving-band, the diameter of which is somewhat larger than that of the bore of the gun, and cut a number of spiral grooves in the barrel. The enormous pressure generated by the explosion of the charge forces the projectile down the bore of the gun and out of the muzzle. The body of the projectile, made of steel or iron, being smaller in diameter than the bore, easily pa.s.ses through, but the driving-band being of greater diameter, and being composed of soft copper, can only pa.s.s down the bore with the projectile by flowing into the grooves, thus preventing any escape of gas, and being forced to follow their twist. It therefore rotates rapidly upon its own longitudinal axis while pa.s.sing down the barrel, and on leaving the muzzle two kinds of velocity have been imparted to it;--first, a velocity of motion through the air; secondly, a velocity of rotation round its axis which causes it to fly steadily onward in the required direction, _i.e._ a prolongation of the axis of the gun. Thus extreme velocity and penetrating power, as well as correctness of aim, are acquired.

The path of a projectile through the air is called its _trajectory_, and if uninterrupted its flight would continue on indefinitely in a perfectly straight line. But immediately a shot has been hurled from the gun by the explosion in its rear two other natural forces begin to act upon it:--

Gravitation, which tends to bring it to earth.

Air-resistance, which gradually checks its speed.

(Theoretically, a bullet dropped perpendicularly from the muzzle of a perfectly horizontal rifle would reach the ground at the same moment as another bullet fired from the muzzle horizontally, the action of gravity being the same in both cases.)

Its direct, even course is therefore deflected till it forms a curve, and sooner or later it returns to earth, still retaining a part of its velocity. To counteract the attraction of gravity the shot is thrown upwards by elevating the muzzle, care being taken to direct the gun's action to the same height above the object as the force of gravitation would draw the projectile down during the time of flight. The gunner is enabled to give the proper inclination to his piece by means of the _sights_; one of these, near the muzzle, being generally fixed, while that next the breech is adjustable by sliding up an upright bar which is so graduated that the proper _elevation_ for any required range is given.

The greater the velocity the flatter is the trajectory, and the more dangerous to the enemy. a.s.suming the average height of a man to be six feet, all the distance intervening between the point where a bullet has dropped to within six feet of the earth, and the point where it actually strikes is dangerous to any one in that interval, which is called the "danger zone." A higher initial velocity is gained by using stronger firing charges, and a more extended flight by making the projectile longer in proportion to its diameter. The reason why a sh.e.l.l from a cannon travels further than a rifle bullet, both having the same muzzle velocity, is easily explained.

A rifle bullet is, let us a.s.sume, three times as long as it is thick; a cannon sh.e.l.l the same. If the sh.e.l.l have ten times the diameter of the bullet, its "nose" will have 10 10 = 100 times the area of the bullet's nose; but its _ma.s.s_ will be 10 10 10 = 1000 times that of the bullet.

In other words, when two bodies are proportional in all their dimensions their air-resistance varies as the square of their diameters, but their ma.s.s and consequently their momentum varies as the _cube_ of their diameters. The sh.e.l.l therefore starts with a great advantage over the bullet, and may be compared to a "crew" of cyclists on a multicycle all cutting the same path through the air; whereas the bullet resembles a single rider, who has to overcome as much air-resistance as the front man of the "crew" but has not the weight of other riders behind to help him.

As regards the effect of rifling, it is to keep the bullet from turning head over heels as it flies through the air, and to maintain it always point forwards. Every boy knows that a top "sleeps" best when it is spinning fast. Its horizontal rotation overcomes a tendency to vertical movement towards the ground. In like manner a rifle bullet, spinning vertically, overcomes an inclination of its atoms to move out of their horizontal path. Professor John Perry, F.R.S., has ill.u.s.trated this gyroscopic effect, as it is called, of a whirling body with a heavy flywheel in a case, held by a man standing on a pivoted table. However much the man may try to turn the top from its original direction he will fail as long as its velocity of rotation is high. He may move the top relatively to his body, but the table will turn so as to keep the centre line of the top always pointing in the same direction.

RIFLES.

Up to the middle of last century our soldiers were armed with the flint-lock musket known as "Brown Bess," a smooth-bore barrel 3/4-inch in diameter, thirty-nine inches long, weighing with its bayonet over eleven pounds. The round leaden bullet weighed an ounce, and had to be wrapped in a "patch" or bit of oily rag to make it fit the barrel and prevent windage; it was then pushed home with a ramrod on to the powder-charge, which was ignited by a spark pa.s.sing from the flint into a priming of powder. How little its accuracy of aim could be depended upon, however, is proved by the word of command when advancing upon an enemy, "Wait till you see the whites of their eyes, boys, before you fire!"

In the year 1680 each troop of Life Guards was supplied with eight rifled carbines, a modest allowance, possibly intended to be used merely by those acting as scouts. After this we hear nothing of them until in 1800 the 95th Regiment received a 20-bore muzzle-loading rifle, exchanged about 1835 for the Brunswick rifle firing a spherical bullet, an improvement that more than doubled its effective range. The companies so armed became known as the Rifle Brigade. At last, in 1842, the old flint-lock was superseded for the whole army by the original percussion musket, a smooth-bore whose charge was exploded by a percussion cap made of copper. [That this copper had some commercial value was shown by the rush of "roughs" to Aldershot and elsewhere upon a field-day to collect the split fragments which strewed the ground after the troops had withdrawn.]

Soon afterward the barrel was rifled and an elongated bullet brought into use. This missile was pointed in front, and had a hollowed base so contrived that it expanded immediately the pressure of exploding gases was brought to bear on it, and thus filled up the grooves, preventing any windage. The one adopted by our army in the year 1852 was the production of M. Minie, a Frenchman, though an expanding bullet of English invention had been brought forward several years before.

Meanwhile the Prussians had their famous needle-gun, a breech-loading rifled weapon fired by a needle attached to a sliding bolt; as the bolt is shot forward the needle pierces the charge and ignites the fulminate by friction. This rifle was used in the Prusso-Austrian war of 1866 some twenty years after its first inception, and the French promptly countered it by arming their troops with the Cha.s.sepot rifle, an improved edition of the same principle. A piece which could be charged and fired in any position from five to seven times as fast as the muzzle-loader, which the soldier had to load standing, naturally caused a revolution in the infantry armament of other nations.

The English Government, as usual the last to make a change, decided in 1864 upon using breech-loading rifles. Till a more perfect weapon could be obtained the Enfields were at a small outlay converted into breech-loaders after the plans of Mr. Snider, and were henceforward known as Snider-Enfields. Eventually--as the result of open compet.i.tion--the Martini-Henry rifle was produced by combining Henry's system of rifling with Martini's mechanism for breech-loading. This weapon had seven grooves with one turn in twenty-two inches, and weighed with bayonet 10 lb. 4 oz. It fired with great accuracy, the trajectory having a rise of only eight feet at considerable distances, so that the bullet would not pa.s.s over the head of a cavalry man.

Twenty rounds could be fired in fifty-three seconds.

Now in the latter years of the century all these weapons have been superseded by magazine rifles, _i.e._ rifles which can be fired several times without recourse to the ammunition pouch. They differ from the revolver in having only one firing chamber, into which the cartridges are one by one brought by a simple action of the breech mechanism, which also extracts the empty cartridge-case. The bore of these rifles is smaller and the rifling sharper; they therefore shoot straighter and harder than the large bore, and owing to the use of new explosives the recoil is less.

The French _Lebel_ magazine rifle was the pioneer of all now used by European nations, though a somewhat similar weapon was familiar to the Americans since 1849, being first used during the Civil War. The Henry rifle, as it was called, afterwards became the Winchester.

The German army rifle is the _Mauser_, so familiar to us in the hands of the Boers during the South African War--loading five cartridges at once in a case or "clip" which falls out when emptied. The same rifle has been adopted by Turkey, and was used by the Spaniards in the late Spanish-American War.

The Austrian _Mannlicher_, adopted by several continental nations, and the Krag-Jorgensen now used in the north of Europe and as the United States army weapon, resemble the Mauser in most particulars. Each of these loads the magazine in one movement with a clip.

The _Hotchkiss_ magazine rifle has its magazine in the stock, holding five extra cartridges pushed successively into loading position by a spiral spring.

Our forces are now armed princ.i.p.ally with the _Lee-Enfield_, which is taking the place of the _Lee-Metford_ issued a few years ago. These are small-bore rifles of .303 inch calibre, having a detachable box, which is loaded with ten cartridges (Lee-Metford eight) pa.s.sed up in turn by a spring into the breech, whence, when the bolt is closed, they are pushed into the firing-chamber. The empty case is ejected by pulling back the bolt, and at the same time another cartridge is pressed up from the magazine and the whole process repeated. When the cut-off is used the rifle may be loaded and fired singly, be the magazine full or empty.

The Lee-Enfield has five grooves (Lee-Metford ten), making one complete turn from right to left in every ten inches. It weighs 9 lb.

4 oz., and the barrel is 30.197 inches long. The range averages 3500 yards.

We are now falling into line with other powers by adopting the "clip"

form instead of the box for loading. The sealed pattern of the new service weapon is thus provided, and has also been made somewhat lighter and shorter while preserving the same velocity.

We are promised an even more rapid firing rifle than any of these, one in which the recoil is used to work the breech and lock so that it is a veritable automatic gun. Indeed, several continental nations have made trial of such weapons and reported favourably upon them. One lately tried in Italy works by means of gas generated by the explosion pa.s.sing through a small hole to move a piston-rod. It is claimed that the magazine can hold as many as fifty cartridges and fire up to thirty rounds a minute; but the barrel became so hot after doing this that the trial had to be stopped.

The princ.i.p.al result of automatic action would probably be excessive waste of cartridges by wild firing in the excitement of an engagement.

It is to-day as true as formerly that it takes on the average a man's weight of lead to kill him in battle.

To our neighbours across the Channel the credit also belongs of introducing _smokeless powder_, now universally used; that of the Lee-Metford being "cordite." To prevent the bullets flattening on impact they are coated with a hard metal such as nickel and its alloys. If the nose is soft, or split beforehand, a terribly enlarged and lacerated wound is produced; so the Geneva Convention humanely prohibited the use of such missiles in warfare.

Before quitting this part of our subject it is as well to add a few words about _pistols_.

These have pa.s.sed through much the same process of evolution as the rifle, and have now culminated in the many-shotted _revolver_.

During the period 1480-1500 the match-lock revolver is said to have been brought into use; and one attributed to this date may be seen in the Tower of London.

Two hundred years ago, Richards, a London gunsmith, converted the ancient wheel-lock into the flint-lock; he also rifled his barrel and loaded it at the breech. The Richards weapon was double-barrelled, and unscrewed for loading at the point where the powder-chamber ended; the ball was placed in this chamber in close contact with the powder, and the barrel rescrewed. The bullet being a soft leaden ball, was forced, when the charge was fired, through the rifled barrel with great accuracy of aim.

The percussion cap did not oust the flint-lock till less than a century ago, when many single-barrelled pistols, such as the famous Derringer, were produced; these in their turn were replaced by the revolver which _Colt_ introduced in 1836-1850. Smith and Wesson in the early sixties improved upon it by a device for extracting the empty cartridges automatically. Livermore and Russell of the United States invented the "clip," containing several cartridges; but the equally well-known _Winchester_ has its cartridges arranged in a tube below the barrel, whence a helical spring feeds them to the breech as fast as they are needed.

At the present time each War Department has its own special service weapon. The German _Mauser_ magazine-pistol for officer's use fires ten shots in ten seconds, a slight pressure of the trigger setting the full machinery in motion; the pressure of gas at each explosion does all the rest of the work--extracts and ejects the cartridge case, c.o.c.ks the hammer, and presses springs which reload and close the weapon, all in a fraction of a second. The _Mannlicher_ is of the same automatic type, but its barrel moves to the front, leaving s.p.a.ce for a fresh cartridge to come up from the magazine below, while in the Mauser the breech moves to the rear during recoil. The range is half a mile. The cartridges are made up in sets of ten in a case, which can be inserted in one movement.

MACHINE-GUNS.

Intermediate between hand-borne weapons and artillery, and partaking of the nature of both, come the machine-guns firing small projectiles with extraordinary rapidity.

Since the United States made trial of Dr. Gatling's miniature battery in the Civil War (1862-1865), invention has been busy evolving more and more perfect types, till the most modern machine-gun is a marvel of ingenuity and effectiveness.

The _Gatling_ machine-gun, which has been much improved in late years by the Accles system of "feed," and is not yet completely out of date, consists of a circular series of ten barrels--each with its own lock--mounted on a central shaft and revolved by a suitable gear. The cartridges are successively fed by automatic actions into the barrels, and the hammers are so arranged that the entire operation of loading, closing the breech, firing and withdrawing the empty cartridge-cases (which is known as their "longitudinal reciprocating motion") is carried on while the locks are kept in constant revolution, along with the barrels and breech, by means of a hand-crank. One man places a feed-case filled with cartridges into the hopper, another turns the crank. As the gun is rotated the cartridges drop one by one from the feed-cases into the grooves of the carrier, and its lock loads and fires each in turn. While the gun revolves further the lock, drawing back, extracts and drops the empty case; it is then ready for the next cartridge.

In action five cartridges are always going through some process of loading, while five empty sh.e.l.ls are in different stages of ejection.