470 DEMOCRITUS AND EPICURUS. 



primary and efficient cause of motion and life 

 in the universe, distinct from the primitive, in- 

 divisible, and immutable atoms of matter ; which 

 he supposed were all of the same essential nature, 

 but different in form and magnitude. It has 

 been said that he referred all the generations and 

 dissolutions of bodies to certain innate forces of 

 attraction and repulsion, residing in these ulti- 

 mate atoms ; and that the various properties of 

 bodies are owing to the different mode of their 

 arrangement, as determined by the inherent 

 powers of atoms. But Lucretius says that De- 

 mocritus regarded heat as composed of exceed- 

 ingly small atoms of a round form, more active 

 and penetrating than those of other matter ; and, 

 the soul or animating principle in man, as a por- 

 tion of the same fiery nature that actuates the 

 universe. With very slight variations, the Epi- 

 curean theory of physics was a copy of the above 

 doctrines. 



Another distinguished teacher of natural phi- 

 losophy among the Greeks, was Pythagoras, the 

 son of a Tyrian merchant, born in the island of 

 Samos 586 A. c. After visiting the different 

 countries of the East, and residing twenty years 

 in Egypt in quest of wisdom, he established a 

 school of science in his native place, and after- 

 wards at Crotona in Western Greece, from which 

 he was driven by persecution to Metapontum, 

 where he is said to have perished of hunger in 



