32 SCIENCE OF THE GREEKS, 



CHAPTER V. 



FROM A.D. 70 TO 20O. 



Ptolemy founds the Ptolemaic System — He writes on Geography — 

 Strabo, a great traveller, writes on Geography — Studies Earth- 

 quakes and Volcanoes — Galen the greatest Physician of Antiquity — 

 Describes the Two Sets of Nerves — Proves that Arteries contain 

 Blood — Lays down a theory of Medicine — Greece and her 

 Colonies conquered by Rome — Decay of Science in Greece — Con- 

 cluding remarks on Greek Science. 



Ptolemy, a.d. 70. — After Hipparchus there were many good 

 astronomers at Alexandria, but none whom we need notice 

 until the year 70 after Christ, when Ptolemy Claudius, a 

 native of Egypt, was bom. He was not one of the Ptole- 

 mies who governed Alexandria, and the place of his birth is 

 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 Hippar- 

 chus, are too complicated for us to discuss here ; they re- 

 lated 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 System 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 contained in Ptolemy's 

 great work called * the Syntaxis.' 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 



