BARREL, a hollow vessel ntade of staves, set on end, arranged around a circle, and bound together with hoops. By each stave being made wider in the middle and tapering a little toward the ends, the barrel is of lamer diameter, or bulges, in the middle. The bevelled edges of the staves cause them to fit closely together making a tight joint along their length. The ends are closed by circular heads, the edges made thin to fit into a groove cut to receive them near the ends of the staves, in which they are held fast by driving the hoops upon the swell of the barrel. The con # struction of the barrel is in eniously.adapted for combining great stren with lightness. It resists pressure from wit out by the arched arrangement of the staves; and the hoops secure it froni the eecpansive force of gases often generated in its contents. Its form is the most convenient for transportation, admitting of the vessel being rolled or rapidly swung by hooks placed under the chine or ends of the staves. In the form of kegs, firkins, liquor caslcs, butts, hogsheads, etc., they are met with
everywhere. Yet the Chinese, with all their ingenuity, it is said, have never made a barrel. Formerly barrels were constructed entirely by hand, the cooper shaving the staves with the draw knife, and shaping them by clamps. But machines are now applied to this purpose, by which the work is done much more expedi tiously. See COOPERAGE.
As a measure of capacity, the barrel is of variable dimensions, differing in size with the materials it is designed to hold. In wine meas ure the barrel must contain 3154 gallons. A barrel of beer in England is equal to 3614 im perial gallons. In the United States a barrel of flour must contain 196 pounds; and a barrel of beef or pork, 200 pounds. The measure of capacity called barrel bulk is fiye cubic feet. Barrel is also used to express any thing long and hollow, as a gun-barrel. It is also applied to the cylinder in a watch, about which the spring is coiled; and in anatomy, to the °cavity of the tympanum° of the ear.