32 SCIENCE OF THE GREEKS. PT. I. 



CHAPTER V. 



FROM A.D. 70 TO 2OO. 



Ptolemy Ptolemaic System Strabo Pliny Galen Greece and her 

 Colonies conquered by Rome Decay of Science in Greece Con- 

 cluding Remarks on Greek Science. 



Ptolemy, A.D. 100. After Hipparchus there were many 

 good astronomers at Alexandria, but none whom we need 

 notice until the period from 100 to 170 after Christ, when 

 Claudius Ptolemy, the great astronomer, flourished. Claudius 

 Ptolemy was a native of Egypt He was not one of the 

 Ptolemies who governed Alexandria, and the place and date 

 of his birth are unknown, but he is famous for having made 

 a regular system of astronomy founded upon all that the 

 Greeks had learnt about the heavens. His discoveries, like 

 those of Hipparchus, are too complicated for us to discuss 

 here ; they related chiefly to the movements of the moon 

 and the planets ; but the one great thing to be remembered 

 of him is, that he founded what is called the Ptolemaic Sys- 

 tem of astronomy, which tries to explain all the movements 

 of the sun, stars, and planets, by supposing the earth to 

 stand still in the centre of them all. This system is con- 

 tained in Ptolemy's great work called 'The Almagest.' It may 

 seem strange that as it is not true that the earth is the centre, 

 Ptolemy should have been able to explain so much by his 

 system, but you must remember that it had the same effect 



