CANNON

A military engine for projecting balls, shells, . by the force of gun-powder. The principal parts of a cannon are, 1. The breech, which is the solid metal from the bottom of the bore or concave cylinder to the extremity of the cascabel, a. 2. The trunnions, h b, which project on each side, and serve to support the cannon in equilibrio, their axis being in the vertical plane pa ing through >the centre of gravity, but intersecting it below that point. 3. The bore or cylindrical cavity. This in several sorts of cannon is made of smaller diameter towards the breech, thus a uming the shape of two cylinders united by a portion of a spherical surface. The smaller part of the bore is of such a length as to receive the maximum service charge of gun-powder, and is called the chamber. The entrance of the bore, c, is called the mouth or muzzle. Cannon are made either of cast iron or bra , the [s. 203]