252 HISTORY OF MINERALOGY. 



diffused very widely his mode of employing external 

 characters. It was, indeed, impossible to attend so 

 closely to these characters as the Wernerian method 

 required, without finding that they were more dis- 

 tinctive than might at first sight be imagined ; and 

 the analogy which this mode of studying mineralogy 

 established between that and other branches of 

 natural history, recommended the method to those 

 in whom a general inclination to such studies was 

 excited. Thus Professor Jameson of Edinburgh, 

 who had been one of the pupils of Werner at Frei- 

 berg, not only published works in which he promul- 

 gated the mineralogical doctrines of his master, but 

 established in Edinburgh a "Wernerian Society," 

 having for its object the general cultivation of 

 natural history. 



Werner's standards and nomenclature of exter- 

 nal characters were somewhat modified by Mohs, 

 who, with the same kind of talents and views, suc- 

 ceeded him at Freiberg. Mohs reduced hardness to 

 numerical measure by selecting ten known minerals, 

 each harder than the other in order, from talc to 

 corundum and diamond, and by making the place 

 which these minerals occupy in the list, the numeri- 

 cal measure of the hardness of those which are 

 compared with them. The result of the applica- 

 tion of this fixed measurement and nomenclature of 

 external characters will appear in the History of 

 Classification, to which we now proceed. 



