SYSTEMATIC MINERALOGY 



CHAPTER VIIT. 



ATTEMPTS AT THE CLASSIFICATION OF MINERALS. 



Sect. 1. Proper object of Classification. 



THE fixity of the crystalline and other physical properties of mine- 

 rals is turned to account by being made the means of classifying 

 such objcets. To use the language of Aristotle, 1 Classification is the 

 architectonic science, to which Crystallography and the Doctrine of 

 External Characters are subordinate and ministerial, as the art of the 

 bricklayer and carpenter are to that of the architect. But classification 

 itself is useful only as subservient to an ulterior science, which shall 

 furnish us with knowledge concerning things so classified. To classify 

 is to divide and to name ; and the value of the Divisions which we 

 thus make, and of the names which we give them, is this ; that they 

 render exact knowledge and general propositions possible. Now the 

 knowledge frhich we principally seek concerning minerals is a know- 

 ledge of their chemical composition ; the general propositions to which 

 we hope to be led are such as assert relations between their intimate 

 constitution and their external attributes. Thus our Mineralogical 

 Classification must always have an eye turned towards Chemistry. We 

 cannot get rid of the fundamental conviction, that the elementary 

 composition of bodies, since it fixes their essence, must determine 

 their properties. Hence all mineral ogical arrangements, whether 

 they profess it or not, must be, in effect, chemical; they must have 

 it for their object to bring into view a set of relations, which, what- 

 ever else they may be, are at least chemical relations. We may 

 begin with the outside, but it is only in order to reach the inner struc 



1 Eth. Nicom. i. 2. 



