﻿cviii PEocEEDiiirGs or the geological societt. [May 1908, 



once to a\7aken the geologists of this country from their long 

 petrographical lethargy. But some nine years seem to have passed 

 away before a single one of them showed by any published paper 

 that he realized the capabilities of the method of research which had 

 now been placed in his hands. In 1867 a paper by David Forbes 

 on 'The Microscope in Geology' was, I think, the first public 

 evidence that the seed sown by Dr. Sorby was beginning to 

 germinate here.^ That seed fell on more responsive soil in Germany, 

 where several geologists began to avail themselves of the new 

 method.^ But it was the energy and enthusiasm of Prof. Zirkel 

 which launched that method into active prosecution on the 

 Continent. Prom the time of his earliest account of it to the 

 Yienna Academy in 1863, he continued year after year to publish 

 papers and separate volumes, dealing with different parts of the 

 subject. These works, with their wealth of new material, and the 

 originality of the conclusions which they established, led the way 

 in the reconstitution of petrography. Prof. Hosenbusch followed 

 with a fuller development of microscopic optics and a brilliant 

 exposition of the whole subject. By these two great leaders, and 

 by the enthusiastic disciples whom they have gathered round them, 

 Germany has been placed in the forefront of the nations in which 

 this study is pursued. 



About a quarter of a century, however, passed away after 

 Dr. Sorby's first indication of the significance of the new method of 

 research, before his example began to be followed in earnest in this 

 country. In 1874 the late Samuel AUport gave to the Geological 

 Society his now classic paper on British Carboniferous Dolerites,^ 



1 Popular Science Review, vol. vi (October 1867) p. 355. It was about 

 the same time that I added a microscope and thin rock-sections to my geological 

 outfit for field-work. In the course of my mapping of the various igneous rocks 

 of Ayrshire for the Geological Survey I had slices prepared from them, of which 

 I availed myself to aid the determinations made in the field. When, in the 

 summer of 1868, Prof. Zirkel paid me a visit at Largs, I was able to show 

 him a series of microscopic slides of the dykes and lavas in the Carboniferous 

 formations of that district : see Zirkel, Zeitschr. Deutsch. Geol. Gesellsch. 

 vol. xxiii (1871) p. 27. 



^ In particular Oschatz, at the meeting of the German Geological Society on 

 January 7th, 1852, referred to the value of the method of preparing thin slices of 

 minerals and inorganic substances, and gave examples of some of the prepara- 

 tions which he had made. On April 5th, 1854, he described further studies of 

 the microscopic structure of rocks, and pointed out the importance of this 

 mode of examination as controlling deductions made from chemical analysis. 

 {Op. cit. vol. iv, p. 13 & vol. vi, p. 261.) 



' Q. J. vol. XXX, p. 529. 



