Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/789

Rh AMMUNITION 745 of troops, but it opens rather more suddenly, segments of iron taking the place of lead and antimony bullets, which segments being built up in a ring with the bursting charge in the centre, are dispersed more widely when the shell opens than.the bullets of the Shrapnel. The segment shell consequently is rather suited for the action of a percussion fuse on striking the head of a column of men, or the ground close in front of it. In this way results have been obtained which are out of all proportion to anything that has ever occurred in actual service. At Dartmoor in 1869 the average number of hits for every segment shell fired during the series of experiments, including failures of all kinds, was 17 1. The meaning of this estimate maybe appre ciated by applying it to some action. For example, at Waterloo the English artillery fired 9467 rounds. On the Dartmoor scale this would give 161,885 casualties. This result shows that after making the most liberal deductions for the peculiar circumstances of war, appalling effects might be produced by modern artillery with segment or Shrapnel shells. Palliser shell and shot are projectiles made with specially hard and rigid heads, with the object of piercing the sides of armour-clad vessels. The form of the head, which is termed &quot;ogival,&quot; is seen inside the gun in Fig. 1. A point of this shape causes the resistance of the plate to fall on the shell as an increasing pressure, acting inwards towards points distributed along the axis, rather than as the full sudden blow that would be experienced by a round shot. This enables chilled iron to be used, which has great hard ness and crushing strength, but is very brittle. Sir W. Palliser first proposed chilled projectiles ; subsequently mottled iron projectiles with chilled heads have been used. Sir J. Whitworth has obtained great results with flat-headed projectiles of a special quality of steel, which have been made to penetrate iron plates at an angle even more oblique than 45. Solid and hollow shot, as well as shell, have been employed against plates. The shot, having thicker sides or walls, have some advantage in penetration. Shells, by their explosion, destroy wood backing better than shot, when the front plating is not too thick for them to pene trate. They are charged with powder through a filling hole in the base of the shell, closed with a strong screw plug. No fuse is required, impact against thick iron being sufficient to explode the bursting charge of a shell without any fuse. The greatest penetration that has yet been obtained in armour was achieved by the 35-ton Woolwich gun (termed the Woolwich &quot; infant &quot;), at Shoeburyness on June 20th, 1872, the head of a Palliser projectile passing entirely through 18 J inches of iron and 12 of teak, a thick ness of armour exceeding that of any iron-clad vessel afloat. Solid shot have gradually disappeared since the introduc tion of rifled guns, and the reasons are obvkms. A round shot fired from a smooth-bored gun, after its first graze, continued to ricochet in a straight line; it produced, there fore, a considerable moral effect, and on smooth ground was actually formidable. A rifled shot, on the other hand, is violently deflected after each graze, from the fact that it is rotating rapidly as it touches the ground, and this, coupled with its liability to bury itself, detracts greatly from its efficiency. Shells for any rifled gun may be made of such length as to bring them to the same weight as the corresponding shot, which was not the case with smooth bore projectiles, they being all of one size instead of one weigM. In short, Palliser shell with thick walls (fired as hollow shot) excepted, the only projectiles of the shot class now employed with rifled guns are case shot. Owing, how ever, to the fact that the charge of a rifled gun varies from ith to th the weight of the projectile, while in smooth- bored guns it was sometimes as great as ^d that of the shot, the effect of rifled case is comparatively weak. At any time the range of case shot hardly exceeds 300 yards, while its efficiency depends on the ground along which it bounds being hard and level. Each shot consists of a number of balls enclosed in a thin metal cylinder, which breaks up in the gun, the balls scattering from the muzzle, but sweep ing the ground with great effect under favourable circum stances. Grape differs only in the balls being larger. At the battle of Friedland, at the bridge of Lodi, and at Sebastopol, grape and case were fired with great effect. Time and percussion fuses have been mentioned. Time fuses are those which open a shell at any given time, whether in the air or during penetration. Fig. 2 shows the &quot; Boxer 9-second fuse &quot; for breech-loading guns, fixed in the shell. On the shell moving, the hammer in the head, by its inertia, shears a copper wire, fires a detonating patch of composition beneath it, and lights the fuse composi tion. This burns until it reaches the point at which a hole is bored in the fuse, when it flashes down the channel shown on the left side of the cut, and fires the powder primer and bursting charge of loose powder. The action of this fuse therefore depends on its correct boring and regular burning. A percussion fuse is one that acts on impact or graze. Fig. 3 shows the Pettman general service fuse. On the first movement of the shell, the detonating ball A, and the plugs above and below it, by their - inertia, crush the lead cap C, and shear the copper pin above F. During flight the ball becomes detached from the upper or steady plug B, and on im pact is fired by its momentum against the part in front of it. The steady plug itself has also a ring of detonating composition, DD, which, should the plug fail to escape from the detonating ball, and so hold against it, is thrown FIG. 3. i, copper parta; 2, against the little plain ball E. The gun flash in either case acts down the tube F, and fires the burst ing charge of the shell. This fuse is made not to explode against a wave, being chiefly used for sea service. It acts both with smooth-bored and rifled guns. For land service more sensitive ones are employed to explode on graze. Friction tubes are copper tubes driven with mealed powder, and pierced from end to end. A friction bar iu the head is rubbed against patches of de tonating composition by pulling a lanyard, which hooks into a loop at the end of it. The tube is entered in the vent of a gun, which is thus fired by pulling the lanyard. For mitrailleuses and breech-loading small arms, lead bullets or lead and tin bullets, fixed in central-fire cartridges, are used. The cases are made of sheet brass, -with a thick base disc containing a cap chamber, cap, and anvil. Fig. 4 shows the Boxer-Henry am munition for the Martini-Henry rifle. These metal-cased cartridges are not liable to ex plode in store, even from the firing of a small charge of powder confined inside the same packing-case with them. They admit of a very rapid rate of firing. The Gatling mitrail leuse has discharged 657 rounds in two minutes at Shoeburyness. The Martini- Henry rifle has fired 25 rounds in a minute. Rockets are projectiles containing composi- tion which, as it burns, generates sufficient gas to drive forward the rocket by an action resembling that of the recoil of a gun. Of rockets there are three kinds : first, per; wrought 7 - bees - wax - war rockets, with iron cases, introduced by Sir W. Congreve, and subsequently I. 94