DOMAIN VII. COMPOSITE. 



as they stimulate their admirers to the ob- 

 servation of facts; and as Werner himself 

 observed to the author at Paris, a theory 

 is useful to concatenate facts, and render 

 them more clear and pleasing to an audi- 

 ence. Nor, with the modesty of a man of 

 real genius, did he conclude his own theory 

 to be unobjectionable. 



The intention of this treatise is the accu- 

 rate knowledge of rocks considered in them- 

 selves. As a Zoologist or a Botanist does 

 not pretend to discriminate which plants 

 or animals are of early or of later creation; 

 and, in the other branches of mineralogy, 

 it is neither the situation nor antiquity of 

 the gem, or the metal, that is an object of 

 the science, but the nature and name of the 

 substance itself. A Gemmologist would be 

 ridiculed if he could not distinguish a blue 

 diamond from a sapphire, without a previ- 

 ous acquaintance whether the object came 

 from Golconda or Pegu ; and a Metallogist 

 must distinguish grey silver ore from anti- 

 mony, without knowing either its formation 

 or site. In the same manner a knowledge 



