CH. I. PYTHAGORAS ON GEOLOGY. u 



somewhere between 566 and 470 B.C. He travelled in 

 Egypt, and learnt much there, and afterwards settled at Ta- 

 rentum, in Italy, where he founded a famous sect called the 

 Pythagoreans. You will read of the opinions of Pythagoras 

 in books of philosophy, but we are only concerned with what 

 he taught about nature. 



He was the first to assert that the earth was not fixed, 

 but moved in the heavens, but he did not know that it 

 moves round the sun. He also discovered that the evening 

 and morning star are the same planet; he called this planet 

 Eosphorus, for it did not receive the name of Venus till some 

 time afterwards. 



Some of the most remarkable truths taught by Pytha- 

 goras were about geology, or the study of the earth. He 

 noticed that seashells were sometimes to be found far inland 

 imbedded in solid ground in a way that showed they were 

 not brought there by man. Therefore, he argued that to 

 bury j-m-shells in the rocks, the sea must once have been 

 there. Pie had also probably watched the sea eating away 

 the cliffs on the shores of Italy, as you may see it doing 

 now on the shores of Norfolk and Suffolk ; and when he 

 was in Egypt he must have seen the Nile carrying mud and 

 laying it down at its mouth, or delta, to form new land. From 

 all these and other observations he, and his pupils who fol- 

 lowed him, drew some very true conclusions which are given 

 in Ovid's ' Metamorphoses' : 



1. Solid land has been converted into sea, 



2. Sea has been changed into land. Marine shells lie 

 far distant from the deep. 



3. Valleys have been excavated by running water, and 

 floods have washed down hills into the sea. 



4. Islands have been joined to the mainland by the 



