PKELUDE TO THE EPOCH OF COPEENICUS. 259 



the Hipparchian or Ptolemaic theories by a long series of great astron- 

 omers of all civilized countries. 



But, though the astronomers who, before Copernicus, held the helio- 

 centric opinion, cannot, on any good grounds, be considered as much 

 more enlightened than their opponents, it is curious to trace the early 

 and repeated manifestations of this view of the universe. The distinct 

 assertion of the heliocentric theory among the Greeks is an evidence 

 of the clearness of their thoughts, and the vigor of their minds ; and 

 it is a proof of the feebleness and servility of intellect in the stationary 

 period, that, till the period of Copernicus, no one was found to try the 

 fortune of this hypothesis, modified according to the improved astro- 

 nomical knowledge of the time. 



The most ancient of the Greek philosophers to whom the ancients 

 ascribe the heliocentric doctrine, is Pythagoras ; but Diogenes Laer- 

 tius makes Philolaus, one of the followers of Pythagoras, the first 

 author of this doctrine. We learn from Archimedes, that it was held 

 by his contemporary, Aristarchus. " Aristarchus of Samos," says 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 Aris- 

 tarchus, 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 centre of the earth and rest there, and therefore 

 the whole mass of the earth cannot 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 Seneca says, 4 it is a worthy subject of contem- 

 plation, 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 mathematicians and good observers at this period, they were 

 employed in cultivating and verifying the Hipparchian theory. 



Next to the Greeks, the Indians appear to have possessed that 



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



3 Quoted by Coperaic. i. 7. 4 Quest. Nat. vii. 2. 



