KEY AND INDEX 



galvanism and the polarization of light. He 

 proved the value of the undulatory theory of 

 light. He continued Oersted's discoveries in 

 electromagnetism, by showing that an unmag- 

 netized bar of steel or iron could be magnetized 

 by a voltaic current. He also showed the fact 

 of magnetization by rotation. 



Archimedes, i, 196. Born cir. 287 B.C. ; killed 

 at capture of Syracuse, 212 B.C. Syracusan 

 mathematician, the most famous of all antiquity. 

 Developed pure geometry, and applied mathe- 

 matical theories to mechanics. Invented hy- 

 draulic screw, and is given credit for explaining 

 principle of lever. Constructed catapults and 

 other engines which delayed the fall of Syracuse 

 (212 B.C.). 



Aristarchus of Samos, i, 212. Lived first half 

 Third Century, B.C. Alexandrian astronomer. 

 Made many observations of which we know only 

 a few. He calculated the relative distances of 

 sun and moon from earth. His theory of calcu- 

 lation was correct, but inaccurate in practice. 

 It is said that with the Pythagoreans he be- 

 lieved the earth to revolve around the sun. 



Aristotle, i, 82. Born at Stagira, 384 B.C.; 

 died at Chalcis, 322 B.C. Greek philosopher 

 and scientist. After living in various places 

 and teaching, he settled at Athens and opened 

 the so-called peripatetic school. As a scientist 

 he treated of astronomy, zoology, mechanics 

 and physics at considerable length. His two 

 chief mental faculties were great aptitude for 

 observation, and a logical method, which lay in 

 the assiduous collection of facts, and the draw- 

 ing of inductions from them. In this he com- 



[60] 



