aicT. iv.] DISSERTATION SECOND. 127 



There are, however, in the reasonings of Copernicus, 

 some unsound parls, which show, that (he power of his 

 genius was not able to dispel all the clouds which in that 

 age hung over the human mind, and that the unfounded 

 distinctions of the Aristotelian physicks sometimes afford- 

 ed arguments equally fallacious to him and !o his adversa- 

 ries. One of his most remarkable physical mistakes was 

 his misconception with respect to the parallelism of the 

 earth's axis ; to account for which, he thought it necessary 

 to assume, in addition to the earth's rotation on an axis, 

 and revolution round the sun, the existence of a third mo- 

 tion altogether distinct from either of the others. In this 

 he was mistaken ; the axis naturally retains its parallelism, 

 and it would require the action of a force to make it do 

 otherwise. This, as Kepler afterwards remarked, is a con- 

 sequence of the inertia of matter ; and, for that reason, he 

 very justly accused Copernicus of not being fully acquaint- 

 ed with his own riches. 



The first edition of the Astronomia Instaurata, the 

 publication of which was solicited by Cardinal Schoen- 

 berg, and the book itself dedicated to the Pope, appeared 

 in 1543, a few days before the death of the author. 

 Throughout the whole book, the new doctrine was ad- 

 vanced with great caution, as if from a presentiment of the 

 opposition and injustice which it was one day to expe- 

 rience. At first, however, the system attracted little no- 

 tice, and was rejected by the greater part even of astrono- 

 mers. It lay fermenting in secret with other new dis- 

 coveries for more than fifty years, till, by the exertions of 

 Galileo, it was kindled into so bright a flame as to consume 

 the philosophy of Aristotle, to alarm the hierarchy of 

 Rome, and to threaten the existence of every opinion not 

 founded on experience and observation. 



