THE PROCESS OF REPRODUCTION. 463 



The best remedy of such feelings is to be found 

 in the history of science. Kepler, when he had 

 been driven to reject the solid epicycles of the 

 ancients, or a person who had admired Kepler as 

 M. Bourdon admires Buffon, but who saw that his 

 magnetic virtue was an untenable fiction, might, 

 in the same manner, have thrown up all hope of a 

 sound theory of the causes of the celestial motions. 

 But astronomers were too wise and too fortunate 

 to yield to such despondency. The predecessors of 

 Newton substituted a solid science of mechanics for 

 the vague notions of Kepler; and the time soon 

 came when Newton himself reduced the motions of 

 the heavens to a law as distinctly conceived as the 

 motions had been before. 



