Archimēdes

, a famous geometrician of Syracuse, who invented a machine of gla that faithfully represented the motion of all the heavenly bodies. When Mar cell us the Roman consul besieged Syracuse Arch i me des constructed machines which suddenly raised up in the air the ships of the enemy from the bay before the city, and let them fall with such violence into the water that they sunk. He set them also on fire with his burning gla es. When the town was taken, the Roman general gave strict orders to his soldiers not to hurt Arch i me des, and he even offered a reward to him who should bring him alive and safe into his presence. All these precautions were usele ; the philosopher was so deeply engaged in solving a problem, that he was even ignorant that the enemy were in po e ion of the town; and a soldier, without knowing who he was, killed him, because he refused to follow him, B.C. 212. Mar cell us raised a monument over him, and placed upon it a cylinder and a sphere; but the place remained long unknown, till Cicero, during his questorship in Sicily, found it near one of the gates of Syracuse, surrounded with thorns and brambles. Some suppose that Arch i me des raised the site of the towns and villages of Egypt, and began those mounds of earth by means of which communication is kept from town to town during the inundations of the Nile. The story of his burning gla es had always appeared fabulous to some of the moderns, till the experiments of Buffon demonstrated it beyond contradiction. These celebrated gla es were supposed to be reflectors made of metal, and capable of producing their effect at the distance of a bowshot. The manner in which he discovered how much bra a goldsmith had mixed with gold in making a golden crown for the king is well known to every modern hydrostatic, as well as the pumping screw which still bears his name. Among the wild schemes of Arch i me des, is his saying that, by means of his machines, he could move the earth with ease, if placed on a fixed spot near it. Many of his works are extant, especially treatises de sphærâ et cylindro, circuli dimensio , de line is spiral i bus , de quadraturâ paraboles , de numero arenæ , . ; the best edition of which is that of David Rivaltius, folio, Paris, 1615. Cicero , Tusculanæ Dis put at i ones , bk. 1 , ch. 25 ; De Natura Deorum , bk. 2 , ch. 34 .— Livy , bk. 24 , ch. 34 .— Quintilian , bk. 1 , ch. 10 .— Vitruvius , bk. 9 , ch. 3 .— Polybius , bk. 7 .— Plutarch , Mar cell us .— Valerius Maximus , bk. 8 , ch. 7 .