ARCHIMEDES

One of the greatest mathematicians and natural philosophers of antiquity, born B.C. 287 at Syracuse. He lived at the court of his kinsman, king Hiero, and was killed (B.C. 212) by a Roman soldier at the taking of the city which he had largely aided in defending with his engines. Of his inventions and discoveries we need only say, that he ascertained the ratio of the radius to the circumference, and that of the cylinder to the sphere, and the hydrostatic law that a body dipped in water loses as much weight as that of the water displaced by it; that he invented the pulley, the endless screw, and the kind of pump called the "screw of Archimedes"; and that he constructed the so-called "sphere," a sort of orrery showing the motions of the heavenly bodies. Of his works, written in the Doric dialect, the following are preserved: On the sphere and cylinder, On the measurement of the circle, On conoids and spheroids, On spiral lines, The psammites (or sand-reckoner, for the calculation of the earth's size in grains of sand), On the equilibrium of planes and their centres of gravity, and On floating bodies.