A CAPTIVE COMET. 



353 



It is now perfectly well known to every schoolboy that the 

 sun is the center and ruler of the solar system ; that the earth and 

 other planets revolve about it in great ellipses. This simple fact 



was not recognized, however, until nearly the middle of the six- 

 teenth century. For thousands of years previously, astronomers 

 as well as priests, the educated and the ignorant, had thought 



VOL. XLII. 24 



