a long piece of metal composed of several links or rings, engaged the one in the other. They are made of divers metals, some round, some flat, others square; some single, some double; and serve to so many uses, that it would be tedious to give a particular account of them all.

CHAIN is also a kind of measure in France, in the trade of wood for fuel: There are chains for wood by tale, for wood by the rope, for faggots, for cleft wood, and for round sticks. There are also chains measuring the sheaves of all sorts of corn, particularly with regard to the payment of tythes; for measuring pottles of hay, hay, and for measuring horses. All these are divided into feet, inches, hands, &c. according to the use they are designed for.

**CHAIN-BOAT**, two bullets with a chain between them. They are used at sea to shoot down yards or masts, and to cut the shrouds or rigging of a ship.

in surveying, a measure of length, made of a certain number of links of iron-wire, serving to take the distance between two or more places.

Gunter's chain of 100 such links, each measuring 7½ inches, and consequently equal to 66 feet, or four poles. See Surveying.