CANNON, in the military art, an en gine or fire-arm for throwing iron, lead, or stone bullets, by force of gun-powder. Cannons at first were called bombardz, from the noise they made ; they had like wise the name of culverin, basilisk, &c. from the beasts that were represented upon them ; and the Spaniards, from de votion, gave them the name of saints ; witness the twelve apostles which Charles V. ordered to be cast at Malaga, for his expedition to Tunis.
Cannon are classed as field-pieces or battering pieces ; the former are usually made of mixed metals, but sometimes of pure brass ; the latter, with very few ex ceptions, are of cast iron. Every can non is made by running fused metal into a mould, and is afterwards finished by be ing turned on a lathe. The chase is bored by means of a strong machine. Some suspend the cannon vertically over the borer, making it press downwards as the borer revolves : others have a horizontal process, in which the cannon is firmly fixed on a frame, and the borer approach es as the chase proceeds. There is a large cylindrical projection on each side of a cannon, nearly in the middle of its length ; these are called trunnions; they serve to support it on the carriage, and as pivots, whereon a due degree of ele vation or depression may be given. The variation in the elevation is made in field pieces, which usually carry balls of 3, 6, 9, 12, and up to 181b. weight, by means of a screw fixed to a strong piece of wood, that joins the two cheeks of the carriage, and is fastened by a loop and bolt to tb,..
round knob at the end of the cannon, called the cascabel. As there is great force in the powder when ignited by means of a match applied to the vent, which communicates with the end of the chase, the quantity of metal must, of ne cessity, be augmented about the breech, or hinder parts. Thus all cannons are fortified in that part ; but battering can nons are generally double-fortified, by an additional quantity of metal, in conse quence of the large charges of powder given, for the purpose of adding to the impetus or force of the shot's action on the place to be battered.
Battering-pieces are generally from 24 to 42 pounders, sometimes 18 pounders are used, but their effect is feeble, com pared with that of cannons of a larger calibre.
Cannon intended for field service are mounted on a carriage, with two stout wheels, about four feet and a half high, on a solid wooden or an iron axle, and suspended by their trunnions on the two cheeks, which are as near to each other as the size of the cannon will permit, tapering down a little towards the ground, at a sufficient angle to oppose the recoil, or run backward, made by every piece when fired. The cheeks diverge a little,
and are kept very firm in their places by means of cross pieces called transoms, which are vertical in and secured by strong bolts. The cannon is turned about to any direction by means of a hand spike which fixes into the train. The • piece is transported by raising its train, and passing the tail-transom, which is perforated for the purpose, on to a very substantial iron gudgeon firmly fixed on the centre of an axle, which has two wheels rather lower than those of the carriage. This appendage is called a lim ber, and carries a stout water-proof box full of ammunition of various descriptions, for the service of the cannon ; it has likewise a pole, or shafts, whereby horses are attached, and the piece thus travels with tolerable ease ; the limber wheels traversing under the cheeks of the car riage.
The modes of charging cannon are va rious, but in general with cartridges, over which wads of spun yarn are well ram med ; then the shot, either round or grape ; and, lastly, a second wad ram med.home : but in field service, where grape or canister shot are used, the whole charge is sometimes made to fit in immediately after the cartridge, which is invariably made of serge, shalloon, or other woollen stuff. Grape is made by putting many small balls together, so as to fit the bore of the piece ; they are usually netted to a round piece of board. Canister is nothing more than a number of still smaller balls put into a tin canis ter; these are intended for close attacks, especially among cavalry, or large bodies of infantry, round shot being mere suit. ed to distant operations. Ship guns, and such others as are intended to be station. ary, are placed on low substantial car riages, moving on four small trucks ; these ere elevated by means of wedges called quoins. Some are discharged by locks, on the same principles as those for mus quets ; and for ship use are certainly the safest, and best adapted to a certainty of aim. Brass six-pounders often weigh so little as 4 cwt. but some of the double for tified battering cannon amount to full 3 tons each.