THE PATH OF EVOLUTION 



still withheld his publications varying and repeating 

 his observations and testing his new theories by calcu- 

 lating their adaptation to explain the most difficult 

 and complicated problems, such as the apparently 

 retrograde motions of the planets, the procession of 

 the equinoxes, etc. Finally, in 1543, his book ap- 

 peared, " De Orbium Celestium Revolutionibus," in 

 which the sun is placed at the centre of the system. 

 Around it the planets revolved in their orbits, which 

 he thought were perfect circles, of which planets the 

 earth was one. It revolved on its axis, and around 

 it its satellite, the moon. He dedicated his book to the 

 Pope, Paul III., saying: "In order that they may not 

 accuse me of fleeing from the judgment of enlight- 

 ened people, and in order that the authority of your 

 Holiness, if you approve this work, may preserve 

 me from the virulence of calumny." 



The first copy of his work was brought to him 

 only when on his deathbed. He touched it, saw it, but 

 his mind was then nearly gone. In a few hours he 

 was dead. 



The system of Copernicus was eagerly adopted by 

 some of the most illustrious savants, but decried by 

 many others. He could offer no other proofs of its 

 truth than its simplicity, in opposition to the com- 

 plexity of the Ptolemaic system. Since his day many 

 proofs are present to us that did not exist in his time. 



48 



