ASTRONOMY. 421 



been the first who paid much attention to astro- 

 nomy, and its antiquity among them is very great. 

 Mankind must have made considerable improve- 

 ment in observing the motions of the heavenly 

 bodies, before they could so far disengage them- 

 selves from the prejudices of sense and popular 

 opinion, as to believe that the earth was not fixed 

 and immoveable. We find, however, that Thales, 

 the Milesian, had, 580 B. C. taught the manner of 

 calculating eclipses ; and even the present system, 

 called the Copernican, because afterwards revived 

 by Copernicus, was publicly taught in Greece by 

 Pythagoras, who probably learned it in the East. 

 This system was retained till Aristotle and his dis- 

 ciples adopted the vulgar idea, which had been « 

 embraced by Ptolemy, an Egyptian, about the 

 year 140. He supposed that the earth was im- 

 movable in the centre of the universe, and that the 

 planets were placed near it ; above them was the 

 firmament of fixed stars, then the crystalline orbs, 

 then the primum mobile, and last of all, the ccelum 

 empyrium, or heaven of heavens. All these vast 

 orbs he supposed to move round the earth in 

 twenty-four hours. This system, absurd as it was, 

 continued to be believed till Copernicus, a native 

 of Poland, revived that of Pythagoras in the year 

 1530. Europe was then immersed in ignorance, 

 and this system was forbid by the clergy to be 

 taught, as being a heresy. The Reformation per- 

 mitted it again to gain ground, and the discoveries 

 of various astronomers, but particularly those of 

 Sir Isaac Newton, assisted by the invention of tele- 

 scopes, have placed it upon the firmest basis, and 

 it is now universally received. 



If you examine the heavens in a clear night, you 

 will discover some stars which have brighter and 



e e 3 



