278 The Founders of Geology LECT. 



hood I had frequent opportunities of seeing these and 

 the other specimens in Mr. Bryson's cabinet, as well 

 as the fine series of fossil woods sliced so long before by 

 Nicol. 



At last Mr. Henry Sorby came to Edinburgh, and had 

 an opportunity of looking over the Bryson collection. He 

 was particularly struck with the series of slices illustrating 

 " fluid-cavities," and at once saw that the subject was one 

 of which the further prosecution could not fail to " lead to 

 important conclusions in geological theory." * He soon 

 began to put the method of thin slices into practice, made 

 sections of mica-schist, 2 and found so much that was new 

 and important, with a promise of such a rich harvest of 

 results, that he threw his whole energy into the investiga- 

 tion for several years, and produced at last in 1858 the well- 

 known memoir, On the Microscopical Structure of Crystals? 

 which marks one of the most prominent epochs of modern 

 geology. I have always felt a peculiar satisfaction in the 

 reflection that though the work of William Nicol was 

 never adequately recognized in his lifetime, nor for 

 many years afterwards, it was his thin slices, prepared 

 by his own hands, that eventually started Mr. Sorby 

 on his successful and distinguished career, and thus 

 opened out a new and vast field for petrographical in- 

 vestigation. 



It is not necessary here to recapitulate the achieve- 

 ments which have placed Mr. Sorby's name at the head of 

 modern petrographers. He, for the first time, showed how, 



1 Quart. Jour. Oeol. Soc. vol. xiv. (1858), p. 454. 



2 Brit. Assoc. Reports, 1856, sections, p. 78. 



3 Quart. Journ. Geol. Soc. vol. xiv. (1858), p. 453. 



