ERA OF THE GREEK AND ALEXANDRIAN SCHOOLS. 



11 



and its use, called forth the strong language of Pliny, who describes it as a thing even 

 hard for a god to perform " Ausus rem etiam Deo improbam." Perhaps, had we an 

 accurate catalogue of the stars, dating back four thousand years, some remarkable varia- 

 tions of position would be discovered, transpiring by slow and imperceptible degrees, 

 which would open views of the universe, which will now require the observations and 

 comparisons of future centuries to develope and confirm. After determining the places of 

 the stars, Hipparchus made a representation of the heavens on the surface of an artificial 

 globe, which appears to have been deposited at Alexandria ; and with him also the happy 

 idea originated of marking the positions of towns in the same manner, by circles drawn 

 through the poles perpendicularly to the equator, or by latitudes and longitudes. When 

 his brilliant career commenced and terminated, is unknown ; but he was born at Nice, in 

 Bithynia, made many of his observations at Rhodes, and was alive in the interval between 

 160 and 125 B. c. He amply merited the epithet applied to him by Ptolemy, " the lover 



of labour and truth," <^I\OWOVOQ Kal 

 0iAaX?/077e ; and is properly classed 

 in scientific opinion with the Brad- 

 leys and Flamsteads of modern 

 times. After him, there is little to 

 invite attention in the history of as- 

 tronomy for nearly three centuries, 

 when we come to Ptolemy, the first 

 who formally broached a system of 

 the universe which has been handed 

 down to us. 



Apart from his theory, Ptolemy 

 has great merits. He was the best 

 scholar of his age a practical 

 astronomer, mathematician, and 

 geographer the author of the im- 

 portant discovery of the evection or 

 libration of the moon. Born in 

 Egypt, and flourishing at Alexan- 

 dria through the reigns of the em- 

 perors Adrian and Antoninus, he 

 there became acquainted with the 

 writings and observations of Hip- 

 parchus. The former, with one 

 exception, unfortunately perished 



at the destruction of the Alexandrian library ; but the chief of the latter have been 

 preserved by Ptolemy in his own works, and they have largely contributed to his fame. 

 In a celebrated production which ruled the mind of Europe for fifteen centuries, the 

 Great Collection, or Almagest, as 'it was called by the Arabic translator, he re- 

 corded the advances of past ages in astronomy, the state of the science in his own 

 time, and developed a plan of the celestial movements. It recognised the earth to 

 be a spherical body for reasons similar to those that are now alleged in proof of 

 its convexity to be the immovable centre of the universe the sun, moon, planets, 

 and fixed stars, prosecuting a daily revolution around it, in perfect circles, and with 

 uniform velocities. This is in accordance with the appearance presented by the first 

 blush of the universe to the physical eye. The sun is seen daily pursuing a course 

 through the heavens in the segment of a circle from east to west. The same path is ap- 



