104 PHYSICAL SCIENCES IN ANCIENT GREECE. 



and severe in their demonstrations as geometry 

 itself, and as copious and interesting in their con- 

 clusions; but which, besides this recommendation, 

 possess one of a different order ; that they exhibit 

 the exact impress of the laws of the physical world; 

 and unfold a portion of the rules according to 

 which the phenomena of nature take place, and 

 must take place, till nature herself shall alter. 



