System of the Universe. 251 



seas, and penetrates into foreign climates, be- 

 comes acquainted with those which he inhabits, 

 and regulates the dates of ages past. 



Hipparchus laid the principal foundations of 

 a methodical system of astronomy one hundred 

 and forty-seven years before Christ. On the ap- 

 pearance of a new fixed star, he took occasion to 

 make a general catalogue of the stars, assigning 

 to each its place in the heavens, and its mag- 

 nitude, so as to enable posterity to ascertain, 

 whether any new star had appeared, or any of 

 those which he had observed had suffered any 

 change. Ptolemy, about two hundred and eighty 

 years afterwards, added his observations to those 

 of Hipparchus ; and by the natural advantage 

 which he possessed over his predecessor, he was 

 enabled to rectify greatly the observations of the 

 former philosopher. Ptolemy was the last of the 

 Greeks who made any considerable improve- 

 ments in the science of astronomy. It was after- 

 wards cultivated by the Arabians with great assi- 

 duity, and success, but did not meet with any 

 encouragement in Europe till about the middle 

 of the 13th century. At this period Alphonsus 

 the Tenth, king of Castile, became its zealous 

 patron, and immortalized himself by a series of 

 astronomical tables, which were published under 

 his direction, and were distinguished by the 

 name of the Alphonsine tables. 



It was not, however, till the sixteenth century 

 that astronomy was placed upon its proper basis 



