28 THE HISTORY OF SCIENCE 



art is ignoble if connected with daily needs. His in- 

 terest lay in abstruse mathematical problems. His 

 special pride was in having determined the relative 

 dimensions of the sphere and the enclosing cylinder. 

 He worked out the principle of the lever. " Give 

 me," he said, " a place on which to stand and I will 

 move the earth." He approximated more closely 

 than the Egyptians the solution of the problem of 

 the relation between the area of a circle and the ra- 

 dius. His work had practical value in spite of him- 

 self. At the request of his friend the King of Sicily, 

 he applied his ingenuity to discover whether a cer- 

 tain crown were pure gold or alloyed with silver, and 

 he hit upon a method which has found many appli- 

 cations in the industries. His name is associated 

 with the endless screw. In fact, his practical contriv- 

 ances won such repute that it is not easy to separate 

 the historical facts from the legends that enshroud 

 his name. He aided in the defense of his native city 

 against the Romans in 212 B.C., and devised war- 

 engines with which to repel the besiegers. After the 

 enemy had entered the city, says tradition, he stood 

 absorbed in a mathematical problem which he had 

 diagrammed on the sand. As a rude Roman soldier 

 approached, Archimedes cried, "Don't spoil my cir- 

 cles," and was instantly killed. The victorious gen- 

 eral, however, buried him with honor, and on the 

 tomb of the mathematician caused to be inscribed 

 the sphere with its enclosing cylinder. The triumphs 

 of Greek abstract thought teach the lesson that prac- 

 tical men should pay homage to speculation even 

 when they fail to comprehend a fraction of it. 



