436 HISTORY OF FORMAL ASTRONOMY. 



inaccuracy. The only way in which he rewarded 

 himself for his trouble, was by describing to the 

 world, in his lively manner, his schemes, exertions, 

 and feelings. 



The mystical parts of Kepler's opinions, as his 

 belief in astrology, his persuasion that the earth 

 was an animal, and many of the loose moral and 

 spiritual as well as sensible analyses by which he 

 represented to himself the powers which he sup- 

 posed to prevail in the universe, do not appear to 

 have interfered with his discovery, but rather to 

 have stimulated his invention, and animated his 

 exertions. Indeed, where there are clear scientific 

 ideas on one subject in the mind, it does not appear 

 that mysticism on others is at all unfavourable to 

 the successful prosecution of research. 



I conceive, then, that we may consider Kepler's 

 character as containing the general features of the 

 character of a scientific discoverer, though some of 

 the features are exaggerated, and some too feebly 

 marked. His spirit of invention was undoubtedly 

 very fertile and ready, and this and his perseverance 

 served to remedy his deficiency in mathematical 

 artifice and method. But the peculiar physiognomy 

 is given to his intellectual aspect by his dwelling in 

 a most prominent manner on those erroneous trains 

 of thought which other persons conceal from the 

 world, and often themselves forget, because they 

 find means of stopping them at the outset. In the 

 beginning of his book (Argumenta Capitum) he 



