PRELUDE TO THE EPOCH OF COPERNICUS. 383 



he 1 , makes this supposition, that the fixed stars and 

 the sun remain at rest, and that the earth revolves 

 round the sun in a circle." Plutarch 2 asserts that 

 this, which was only a hypothesis in the hands of 

 Aristarchus, was proved by Seleucus ; but we may 

 venture to say that, at that time, no such proof was 

 possible. Aristotle had recognized the existence of 

 this doctrine by arguing against it. " All things," 

 says he 3 , " tend to the center of the earth, and rest 

 there, and therefore the whole mass of the earth can- 

 not rest except there." Ptolemy had in like manner 

 argued against the diurnal motion of the earth : 

 such a revolution would, he urged, disperse into 

 surrounding space all the loose parts of the earth. 

 Yet he allowed that such a supposition would 

 facilitate the explanation of some phenomena. 

 Cicero appears to make Mercury and Venus revolve 

 about the sun, as does Martianus Capella at a later 

 period; and kSsneca says 4 , it is a worthy subject of 

 contemplation, whether the earth be at rest or in 

 motion: but at this period, as we may see from 

 Seneca himself, that habit of intellect which was 

 requisite for the solution of such a question, had 

 been succeeded by indistinct views, and rhetorical 

 forms of speech. If there were any good mathe- 

 maticians and good observers at this period, they 

 were employed in cultivating and verifying the Hip- 

 parchian theory. 



1 Archim. Arenarius. 2 Quest. Plat. Delamb. A. A. vi. 

 3 Copernic. i. 7- 4 Quest. Nat. vii. 2. 



