PROGRESS OF PHYSICAL GEOLOGY. 649 



general truths, such as the philosophers of moderji 

 times have only satisfied themselves of by long and 

 patient labour and thought. If resemblances should 

 be discovered between the assertions of ancient 

 writers and the discoveries of modern science, the 

 probability in all cases, the certainty in most, is, 

 that these are accidental coincidences ; that the 

 ancient opinion is no anticipation of the modern 

 discovery, but is one guess among many, not a whit 

 the more valuable because its expression agrees 

 with a truth. The author of the guess could not 

 intend the truth, because his mind was not pre- 

 pared to comprehend it. Those of the ancients who 

 spoke of the harmony which binds all things to- 

 gether, could not mean the Newtonian gravitation, 

 because they had never been led to conceive an 

 attractive force, governed by definite mathematical 

 laws in its quantity and operation. 



In agreement with these views, we must, I con- 

 ceive, estimate the opinions which we find among 

 the ancients, respecting the changes which the 

 earth's surface has undergone. These opinions, 

 when they are at all of a general kind, are arbitrary 

 fictions of the fancy, showing man's love of gene- 

 rality indeed, but indulging it without that expense 

 of labour and thought which alone can render it 

 legitimate. 



We might, therefore, pass by all the traditions 

 and speculations of Oriental, Egyptian, and Greek 

 cosmogony, as extraneous to our subject. But 



