VISIT TO EUROPE: RESIDENCE IN EDINBURGH. 169 



evaporation to form the clouds, those exhaustless store- 

 houses of rain, snow, and hail. But in the progress of this 

 endless circulation, it is everywhere obvious that water 

 produces extensive and highly important geological results, 

 in the transportation and deposition of solid as well as of 

 dissolved materials, in the formation and disintegration of 

 strata, and especially in the ceaseless wear of rivers and 

 torrents, and in the never-ending motions of the oceans 

 and seas in tidal waves and storm billows and currents. It 

 is not wonderful, then, that the powerful mind of Werner 

 should appreciate, and even exaggerate, these agencies. 

 He had not travelled far away from his own (geologically) 

 peaceful Saxony, and knew little from personal observations 

 of the agencies of internal fire. He founded his system, 

 therefore, upon a partial and imperfect view of evidence ; 

 but his zeal and eloquence captivated his numerous pupils, 

 whose delight it was to blazon the system of their great 

 teacher ; and for many years few were bold enough to 

 question its entire truth. But a change of opinion had 

 been for some years going on. The philosophy of fire as 

 regards its agencies in the earth not entirely new in- 

 deed had been revived and greatly extended by the re- 

 searches of Dr. Hutton of Edinburgh, aided by his enthu- 

 siastic followers, Play fair, Hall, Hope, Seymour and others. 

 The followers of Hutton were now organized into a geolog- 

 ical phalanx, and my residence in Edinburgh occurred at 

 the fortunate crisis, when the combatants on both sides 

 were in the field ; and I, although a non-combatant, was 

 within the wind of battle, and prepared, like victory, to join 

 the strongest side. When Dr. Hope came out with his 

 array of facts in support of the Huttonian theory, I was in 

 a state of mind to yield to evidence. Being a young man, 

 uncommitted to either theory, I was a deeply interested 

 listener to the discussions of both the Wernerian and Hut- 

 tonian hypothesis. From the fierce central heat of the 

 philosophers of fire, and its destructive heavings and irrup- 



