EPROUVETTE

From Agepedia

EPROUVETTE ; the name of an instrument for ascertaining the strength of fired gunpowder, or of comparing the strength of different kinds of gunpowder. One of the best, for the proof of powder in artillery, is that contrived by doctor Hutton. It consists of a small brass gun, about 2£ feet long, suspended by a metallic stem, or rod, turning by an axis, on a firm and strong frame, by means of which the piece oscillates in a circular arch. A little below the axis, the stem divides into two branches, reaching down to the gun, to which the lower ends of the branches are fixed, the one near the muzzle, the other near the breech of the piece. The upper end of the stem is firmly attached to the axis, which turns very freely by its extremities in the sockets of the supporting frame, by which means the gun and stem vibrate together in a vertical plane, with a very small degree of friction. The piece is charged with a small quantity of powder (usually about two ounces), without any ball, and then fired; by the force of the explosion, the piece is made to recoil or vibrate, describing an arch or angle, which will be greater or less according tcUhe quantity or strength of the powder.