COPERNICUS 



when 27 years old, to the professorship of mathematics. 

 After a short time spent in Thorn he returned to Italy, 

 but in 1503 left for Cracow, where he was made a 

 priest. He settled finally in 1510 at Frauenberg on the 

 shores of the Baltic. Here he built an observatory 

 and perfected his astronomical labors. Copernicus had 

 studied all the works on astronomy that had come 

 down from antiquity. He was probably acquainted 

 with those of Nicholas of Cusa, who had preceded 

 him in his theory nearly two generations. Cusa's 

 works were published in Paris in 1514. Copernicus 

 saw that the system described by Apollonius of Perge 

 the author of Epicycles that placed the sun in 

 the centre of the planets' orbits, but caused it to 

 move like the moon around the earth (the system 

 afterwards adopted by Tycho-Brahe), was much 

 simpler than the Ptolemaic, and explained better the 

 movement of Venus and Mars; but it did not satisfy 

 his own required conditions for the earth. He com- 

 pleted his new Astronomy about 1512, but from diffi- 

 dence and distrust of himself, as well as from the fear 

 of ridicule, it was not published to the world until 

 1543, at Nuremberg, when he was 70 years of age. 

 This fear of ridicule was well founded, for there is 

 nothing so sure of itself or so intolerant as ignorance. 

 As early as 1530, the report of his novel views had 

 spread far and wide among the astronomers; but he 



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