OPINIONS OF THE GREEKS. 105 



Let us continue. According to the Chaldeans, who were 

 thought to be profoundly versed in astronomy, the earth was 

 hollow, and shaped like an egg-shell. And, adds Diodorus, 

 from whom we have this detail, they adduce numerous and 

 plausible proofs of this assertion. 



Yet was this idea in direct opposition to the evidence of our 

 senses when we travel over a wide plain, or navigate the great 

 deep ; at least, unless we admit that the earth has the form of 

 a reversed egg-shell, with its convex face uppermost, and its 

 concave one beneath. Heraclitus of Ephesus introduced the 

 Chaldean doctrine into Greece. 



Anaximander represents the earth as a cylinder, whose 

 upper face alone is inhabited. This cylinder, adds the philo- 

 sopher, is a third of its diameter in height, and floats freely in 

 the midst of the celestial vault, because there is no reason 

 why it should move more to one side than the other. Leucip- 

 pus, Democritus, Heraclitus, and Anaxagoras, names of high 

 repute in the history of philosophy, adopted Anaximander's 

 system, though it was neither more nor less than a wild 

 phantasy. 



Anaximenes and Zenophanes, without pronouncing dog- 

 matically on the form of the earth, represented it as resting, 

 the one upon compressed air, the other upon roots which 

 were prolonged ad infinitum. But upon what was the com- 

 pressed air supported ? And of what nature were these mys- 

 terious roots ? 



Plato, with a nearer approximation to the probable, gave 

 to the earth the form of a cube. The cube, bounded by six 



