among builders, an iron fastening fixed to doors and windows. They are generally distinguished into three kinds, viz. plate, round, and spring bolts.

BOLTS, in Gunnery, are of several sorts; as, 1. Tranfum-bolts, that go between the cheeks of a gun-carriage, to strengthen the tranfums. 2. Prife bolts; the large knobs of iron on the cheeks of a carriage, which keep the handspike from sliding, when it is poizing up the breech of a piece. 3. Traverfe bolts; the two short bolts, that, being put one in each end of a mortar carriage, serve to traverfe her. 4. Bracket-bolts; the bolts that go through the cheeks of a mortar, and by the help of quoins keep her fixed at the given elevation. And, 5. Bed bolts; the four bolts that fasten the brackets of a mortar to the bed.

BOLTS, in a ship, are iron pins, of which there are several sorts, according to their different makes and uses. Such are drive-bolts, used to drive out others. Ray-bolts, with jags or barbs on each side, to keep them from flying out of their holes. Clench-bolts, which are clenched with riveting hammers. Forelock-bolts, which have at the end a forelock of iron driven in to keep them from starting back. Set-bolts used for forcing the planks, and bringing them close together. Fend or fender bolts, made with long and thick heads, and struck into the uttermost bends of the ship, to save her sides from bruises. And ring-bolts, used for bringing to of the planks, and those parts whereto are fastened the breeches and tackling of the guns.

BOLT of Canvas, in commerce, the quantity of 28 ell.

BOLT-Rope, in naval affairs, a rope passing round the sail, to which the edges of it are fewed, to prevent the sail from tearing: the bottom part of it is called the foot-rope; the side leeches; and if the sail be oblong or square, the upper part is called the head-rope.