272 PROGRESS OF SCIENCE IN THE CENTURY. 



of making sections -was published in 1831.* But 

 these early hints had little result, and it seems fairly 

 certain that the first to use and appreciate the method 

 of studying thin rock-sections in transmitted lino 

 under the microscope was Dr. H. Clifton Sorby of 

 Sheffield (1850), who had been stimulated by tho 

 eight of a collection of Nicol's preparations which 

 had been preserved and added to by Alexander Bry- 

 son, an optician in Edinburgh. 



Professor Zittel notes that, in 1852, Oschatz ex- 

 hibited in Berlin a series of microscopic sections of 

 rocks which ho had made, but hia results seem to 

 have been regarded as little more than curiosities. 

 A proof of the value of the method was needed, and 

 that was furnished in 1858 by Sorby in a classic 

 memoir " On tho microscopic study of crystals, indi- 

 cating the origin of minerals and rocks." f Tho 

 next steps, and for many years almost all the im- 

 portant steps, were taken by continental geologists. 

 " Even Sorby's papers, which continued to be most 

 suggestive in this lino of work, had reference only 

 to very special points; and it may bo doubted if his 

 greatest service was not tho transplanting of his ideas 

 and methods to Germany, where they wero destined 

 to rapidly take root, and bear a fruitful harvest"}: 



It was a most fortunate thing for science that 

 Zirkel, as a young student, made Sorby's acquaint- 

 ance in Bonn in 18G2, and after many walks and 

 talks became an enthusiastic disciple, soon far to 



Henry Withani. O6srtafion* on Fo*il Vffjetables, 

 Edinburgh, 1881. 8*e The Microicopt, by Carpenter aud 

 DalHnger, London (1801), p. 900. 



f Quart. Journ. Gcol. 800. XIV. (18M), pp. 453-500. 



$ O. H. Williams. Modern Petrography, nn account of the 

 nnpl irat'.on of the microscope to the stud/ of geology. 

 Buetou, IboO. 



