252 Sir Frederick Mohs, Professor of Minei-alogy at Vienna. 



where hopes were then entertained of finding this mineral. A 

 number of the results of these investigations have been pub- 

 hshed in the Transactions of the Polytechnic Institute of Vienna, 

 and have given rise to several new manufactories in Bohemia. 

 He became known to the Archduke John, who at that time 

 contemplated the estabhshment of the Johanneum at Gratz. 

 At the suggestion of the Archduke he undertook another jour- 

 ney into Stiria, upon which the State of that place appointed 

 him Professor of Mineralogy in the Johanneum. In the exten- 

 sive and excellent mineralogical collection in the Institute, the 

 whole of which, together with the apparatus, was a donation 

 from the founder, he had an opportunity of proving and apply- 

 ing his principles and opinions regarding mineralogy. 



In 1812 he commenced his lectures on mineralogy, in which 

 he considered the natural history of the mineral kingdom, and 

 at the same time attempted an elementary method for determin- 

 ing the natural arrangement of the mineral species. In these 

 lectures he always expressed the highest esteem for his cele- 

 brated instructor Werner, without, however, generally following 

 his views. The arrangement and distribution of the mineral 

 collection according to natural principles, met with great ap- 

 plause ; and Professor Mohs himself, in his later writings, men- 

 tions this arrangement as a principal cause of the rapid progress 

 of his pupils. His attempts to make out the specific differences 

 that characterize the divisions of his natural system being at first 

 attended with great difficulties, obliged him to make innumer- 

 able experiments on the hardness and specific gravity of mine- 

 rals. In mineralogical writings he found these characteristics 

 entirely omitted, or if they were mentioned, it was but very 

 inaccurately. This induced him to draw out a scheme of his 

 scale of hardness, and of a system of crystallography, which 

 should be more fundamental than that generally prevalent in 

 Germany, and at the same time simpler and more agreeable to 

 nature than that of the celebrated French mineralogist Haliy. 

 In 1816 Mohs wrote an essay to Professor Jameson in Edin- 

 burgh, with the design of communicating a general explanation 

 of his natural mineralogical method, which this gentleman print- 

 ed in the Edinburgh Philosophical Journal. 



