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. Transom-bolts, that go between the cheeks of a gun carriage, to strengthen the transoms.

2. Prife bolts; the large knobs of iron on the cheeks of a carriage, which keep the hand-spike from sliding, when it is poising up the breech of a piece.

3. Traverse bolts; the two short bolts, that, being put one in each end of a mortar carriage, serve to traverse 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,

(a) Prints of this impression are very rare, and at sales have been known to fetch from £25 to £30. 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 whereunto are fastened the breeches and tackle of the guns.

Bolt of Canvas, in commerce, the quantity of 28 ells.

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