CH. II. ANAXAGORAS STUDIES THE MOON. 13 



CHAPTER II. 



499 TO 322 B.C. 

 Anaxagoras Hippocrates Eudoxus Democritus Aristotle. 



Anaxagoras, who was the next great teacher after Pytha- 

 goras, was born in Ionia about 499 B.C., but he went when 

 quite young to Athens. He loved to study nature for its 

 own sake, and was once heard to say that he was born to 

 contemplate the sun, moon, and heavens. Although there 

 were no telescopes in those days, he managed to observe 

 that there were mountains, plains, and valleys in the moon. 

 He believed it to be a second earth, perhaps with living 

 beings in it. He did not know, as we do now, that the 

 moon has no atmosphere round it, such as living beings 

 like ourselves require in order to breathe. He discovered 

 that an eclipse of the sun is caused by the moon coming 

 directly between the earth and the sun, and an eclipse of 

 the moon by the earth coming between the moon and the 

 sun. When the moon comes exactly between our earth 

 and the sun, we see the moon's dark body pass over the 

 sun, so as to eclipse or shut it out ; and when our earth 

 comes exactly between the moon and the sun we cut off the 

 sun's light from the moon, and see our own shadow passing 

 over the moon's face, and thus we eclipse the moon. 



Anaxagoras knew that the planets Jupiter, Saturn, Venus, 

 Mars, and Mercury move in the heavens, and that the stars 



