ARTILLERY TACTICS. [Illustration: Letter C.] Cannon took their name from the French word _Canne_, a reed. Before their invention, machines were used for throwing enormous stones. These were imitated from the Arabs, and called _ingenia_, whence engineer. The first cannon were made of wood, wrapped up in numerous folds of linen, and well secured by iron hoops. The true epoch of the use of metallic cannon cannot be ascertained; it is certain, however, that they were in use about the middle of the 14th century. The Engraving beneath represents a field-battery gun taking up its position in a canter. The piece of ordnance is attached, or "limbered up" to an ammunition carriage, capable of carrying two gunners, or privates, whilst the drivers are also drilled so as to be able to serve at the gun in action, in case of casualties. [Illustration: TAKING UP POSITION.] Having reached its destination, and been detached or "unlimbered" from the front carriage, we next see the action of loading; the ramrod having at its other extremity a sheep-skin mop, larger than the bore of the piece, and called "a sponge." This instrument, before loading, is invariably used, whilst the touch-hole or "vent" is covered by the thumb of the gunner especially numbered off for this important duty; and the air being thus excluded, the fire, which often remains within the bore, attached to either portions of cartridge-case or wadding, is extinguished. Serious accidents have been known to occur from a neglect of this important preliminary to loading; as a melancholy instance, a poor fellow may be seen about the Woolwich barracks, _both_ of whose arms were blown off above the elbow joint, whilst ramming home a cartridge before the sponge had been properly applied. [Illustration: LOADING.] [Illustration: FIRING IN RETREAT.] If it is deemed essential to keep up a fire upon the enemy during a temporary retreat, or in order to avoid an overwhelming body of cavalry directed against guns unsupported by infantry, in that case the limber remains as close as possible to the field-piece, as shown in the Engraving above. Skilful provisions are made against the various contingencies likely to occur in action. A wheel may he shattered by the enemy's shot, and the gun thereby disabled for the moment: this accident is met by supporting the piece upon a handspike, firmly grasped by one or two men on each side, according to the weight of the gun, whilst a spare wheel, usually suspended at the back of "the tumbril," or ammunition waggon, is obtained, and in a few moments made to remedy the loss, as represented above. [Illustration: DISABLED WHEEL.] [Illustration: DISMANTLING A GUN.]