CH. xxvi. HUTTON ON GEOLOGY. 219 



Neptunists, or those who thought all rocks were laid down 

 by water, and the Vulcanisis, who contended that many rocks, 

 such as basalt, were made by volcanic heat. 



Button teaches that it is by the Study qf Changes 

 going on now that we can alone learn the History of the 

 Past. While these discussions were going on upon the 

 Continent, a Scotchman was setting to work in the right 

 way to settle the question. This man was Dr. Hutton, 

 one of the greatest geologists that has ever lived ; and the 

 reason of his greatness was the same which we have found at 

 every step in our history of science. Before he made any 

 theory he sought out the facts. He travelled and observed 

 for himself, he collected patiently details about the layers or 

 strata in the formations of all countries through which he 

 passed ; and it was only after all these investigations that in 

 1788, when he was sixty years of age, he wrote his famous 

 ' Theory of the Earth,' in which he showed how the history 

 of the earth's crust might be traced out. This work, al- 

 though very interesting, was not much read ; but one of 

 Hutton's favourite pupils, the celebrated Dr. Playfair, wrote 

 a book called ' Illustrations of the Huttonian Theory,' by 

 means of which Hutton's opinions became well known. 



About Hutton himself there is very little to tell. He was 

 born in Edinburgh in 1726, studied medicine, and took his 

 doctor's degree in Leyden in 1749, and then returned to 

 Edinburgh, and devoted all his life to science. Of his 

 teaching I should like to write a great deal, but we must 

 content ourselves with a little which you can understand. 

 His great principle was that it was useless to try and guess 

 how the rocks had been made and fossils buried in them, 

 for this had only led to endless confusion and disputes. 

 Men must go, he said, and see with their own eyes how 



