The well-known piece of artillery, mounted in battery on board or on shore, and made either of brass or iron. The principal parts are:
1st. The breech, together with the cascable and its button, called by seamen the pommelion. The breech is of solid metal, from the bottom of the concave cylinder or chamber to the cascable. 2d. The trunnions, which project on each side, and serve to support the cannon, hold it almost in equilibrio. 3d. The bore or caliber, is the interior of the cylinder, wherein the powder and shot are lodged when the cannon is loaded. The entrance of the bore is called the mouth or muzzle. It may be generally described as gradually tapering, with the various modifications of first and second reinforce and swell, to the muzzle or forward end. (See gun.)