in antiquity, a military engine contrived for the throwing of arrows, darts, and stones upon the enemy.—Some of these engines were of such force that they would throw stones of an hundred weight. Josephus takes notice of the surprising effects of these engines, and says, that the stones thrown out of them beat down the battlements, knocked off the angles of the towers, and would level a whole file of men from one end to the other, was the phalanx ever so deep. This was called the Battering CATAPULTA, and is represented on Plate LXXII. fig. 1. This catapulta is supposed to carry a stone, &c. of an hundred weight, and therefore a description of it will be sufficient to explain the doctrine of all the rest; for such as threw stones of twelve-hundred and upwards were constructed on the same principles.

The bale is composed of two large beams 2, 3. The length of those beams is fifteen diameters of the bore of the capitals 9. At the two extremities of each beam, two double mortises are cut to receive the eight tenons of two cross beams, each of them four of the diameters in length. In the centre of each of the beams of the bale, and near two thirds of their length, a hole, perfectly round, and 16 inches in diameter, should be bored: these holes must be exactly opposite to each other, and should increase gradually to the inside of the beams, so that each of them, being 16 inches on the outside towards the capitals 9, should be 17½ at the opening on the inside, and the edges carefully rounded off. The capitals 9 are, in a manner, the foul of the machine, and serve to twist and strain the cordage, which form its principle or power of motion.

The capitals are either of calf brafs, or iron; each consisting of a wheel with teeth, C 10, of 2½ inches thick. The hollow or bore of these wheels should be 11½ inches in diameter, perfectly round, and the edges smoothed down. As the friction would be too great, if the capitals rubbed against the beams by the extreme straining of the cordage, which draws them towards these beams, that inconvenience is remedied by the means of eight friction-wheels, or cylinders of brafs, about the 13th of an inch in diameter, and an inch and one fifth in length, placed circularly, and turning upon axes, as represented at D 13, and B 12. One of these friction-wheels at large with its screw, by which it is fastened into the beam, is represented at A.

Upon this number of cylindrical wheels the capitals 9 must be placed in the beams 2, 3, so that the cylinders do not extend to the teeth of the wheels, which must receive a strong pinion 14. By the means of this pinion the wheel of the capital is made to turn for straining the cordage with the key 15. The capital wheel has a strong catch 16, and another of the same kind may be added to prevent anything from giving way through the extreme and violent force of the strained cordage.

The capital-piece of the machine is a nut or cross-pin of iron, 17, seen at C, and hammered cold into its form. It divides the bore of the capitals exactly in two equal parts, and fixed in grooves about an inch deep. This piece, or nut, ought to be about two inches and one third thick at the top 18, as represented in the section at B; and rounded off and polished as much as possible, that the cords folded over it may not be hurt or cut by the roughness or edges of the iron. Its height ought to be eight inches, decreasing gradually in thickness to the bottom, where it ought to be only one inch. It must be very exactly inserted in the capitals.

After placing the two capitals in the holes of the two beams in a right line with each other, and fixing the two cross diametrical nuts or pieces over which the cordage is to wind, one end of the cord is reeved through a hole in one of the capitals in the bale, and made fast to a nail within-side of the beam. The other side of the cord is then carried through the hole in the opposite beam and capital, and so wound over the cross-pieces of iron in the centre of the two capitals, till they are full, the cordage forming a large slack. The tension or straining of the cordage ought to be exactly equal, that is, the several foldings of the cord over the capital-pieces should be equally strained, and so near each other as not to leave the least space between them. As soon as the first folding or slack of cord has filled up one whole space or breadth of the capital-pieces, another must be carried over it; and so on, always equally straining the end till no more will pass through the capitals, and the slack of cordage entirely fills them, observing to rub it from time to time with soap.

At three or four inches behind the cordage, thus wound over the capital pieces, two very strong upright beams 21 are raised: these are pots of oak 14 inches thick, crossed over at top by another of the same solidity. The height of the upright beams is 7½ diameters; each supported behind with very strong props 25, fixed at bottom in the extremities of the bale 2, 3. The cross-beam 24 is supported in the same manner by a prop in the centre.

The tree, arm, or stylus 22, should be of sound ash. Its length is from 15 to 16 diameters of the bore

in ornithology, the trivial name of a species of LARUS.