street to his home shouting εὕρηκα, εὕρηκα.

It was in connexion with his discovery of the solution of the problem To move a given weight by a given force that Archimedes uttered the famous saying, “Give me a place to stand on, and I can move the earth” (δός μοι ποῦ στῶ καὶ κινῶ τὴν γᾶν, or in his broad Doric, as one version has it, πᾶ βῶ καὶ κινῶ τὰν γᾶν). Plutarch represents him as declaring to Hieron that any given weight could be moved by a given force, and boasting, in reliance on the cogency of his demonstration, that, if he were given another earth, he would cross over to it and move this one.

“And when Hieron was struck with amazement and asked him to reduce the problem to practice and to show him some great weight moved by a small force, he fixed on a ship of burden with three masts from the king’s arsenal which had only been drawn up by the great labour of many men; and loading her with many passengers and a full freight, sitting himself the while afar off, with no great effort but quietly setting in motion with his hand a compound pulley, he drew the ship towards him smoothly and safely as if she were moving through the sea.” Hieron, we are told elsewhere, was so much astonished that he declared that, from that day forth, Archimedes’s word was to be accepted on every subject!

Another version of the story describes the machine used as a helix; this term must be supposed to refer to a screw in the shape of a cylindrical helix turned by a handle and acting on a cog-wheel with oblique teeth fitting on the screw.

Another invention was that of a sphere constructed so as to imitate the motions of the sun, the moon, and the five planets in the heavens. Cicero actually saw this contrivance, and he gives a description of