CLASSIFICATION OF MINERALS. 257 



assumption, its place in the system conveys to us 

 chemical knowledge concerning it. 



But as the other branches of Natural History, 

 and especially Botany, assumed a systematic form, 

 many mineralogists became dissatisfied with this 

 casual and superficial mode of taking account of 

 external characters; they became convinced, that 

 in mineralogy as in other sciences, classification 

 must have its system and its rules. The views 

 which Werner ascribes to his teacher, Pabst von 

 Ohain 3 , show the rise of those opinions which led 

 through Werner to Mohs : " He was of opinion that 

 a natural mineral system must be constructed by 

 chemical determinations, and external characters at 

 the same time (methodus mixta) ; but that along 

 with this, mineralogists ought also to construct and 

 employ what he called an artificial system, which 

 might serve us as a guide (loco indicis} how to 

 introduce newly-discovered fossils into the system, 

 and how to find easily and quickly those already 

 known and introduced." Such an artificial system 

 containing, not the grounds of classification, but 

 marks for recognition, was afterwards attempted by 

 Mohs, and termed by him the Characteristic of his 

 system. 



Werner's System. But, in the mean time, Wer- 

 ner's classification had an extensive reign, and this 

 was still a mixed system. Werner himself, indeed, 

 never published a system of mineralogy. " We 



3 Frisch. Werner's Leben, p. 15. 

 VOL. III. S 



