Arch i me des

(a ˙ r-ki-mē´dēz), a celebrated ancient Greek physicist and geometrician, born at Syracuse, in Sicily, about 287 B.C. He devoted himself entirely to science, and enriched mathematics with discoveries of the highest importance, upon which the moderns have founded their admeasurements of curvilinear surfaces and solids. Arch i me des is the only one among the ancients who has left us anything satisfactory on the theory of mechanics and on hydrostatics. He first taught the hydrostatic principle to which his name is attached, "that a body immersed in a fluid loses as much in weight as the weight of an equal volume of the fluid", and determined by means of it that an artist had fraudulently added too much alloy to a crown which King Hiero had ordered to be made of pure gold. He discovered the solution of this problem while bathing; and it is said to have caused him so much joy that he hastened home from the bath undre ed, and crying out, Eurēka! Eurēka! 'I have found it, I have found it!' Practical mechanics also received a great deal of attention from Arch i me des, who boasted that if he had a fulcrum or stand-point he could move the world. He is the inventor of the compound pulley, probably of the endle screw, the Arch i me dean screw, . During the siege of Syracuse by the Romans he is said to have constructed many wonderful machines with which he repelled their attacks, and he is stated to have set on fire their fleet by burning-gla es. At the moment when the 223 Romans gained po e ion of the city by a ault (212 B.C. ), tradition relates that Arch i me des was slain while sitting in the market-place contemplating some mathematical figures which he had drawn in the sand.