made by him during his residence at 

 Cambridge ; therefore before the spring 

 of the year 1 760 when his Earthquake 

 paper was presented to the Royal Society. 

 He never published any further contri- 

 butions to geology. It has not unnaturally 

 been inferred that he abandoned that 

 branch of science, in order to devote him- 

 self to the severer studies of which the 

 fruits were given in his subsequent papers. 

 But the truth is that his interest in geo- 

 logical questions remained unabated to 

 the end. Proof of this continued zeal is to 

 be found in a long letter of the year 1788, 

 hitherto unpublished, written by Michell 

 to Henry Cavendish, which has fortu- 

 nately been preserved among the papers 

 of that great philosopher. It vividly in- 

 dicates how keenly its writer, in his 

 journeys to and from London, kept him- 

 self on the watch for any fresh pit, 

 quarry or other exposure of the rocks 

 below the surface. 



It appears that Cavendish, for some 



45 



