314 HISTOBY OF MINERALOGY" 



and unsystematic distribution cannot, in the cases we now have to 

 consider, answer the purposes of exact and general knowledge. Our 

 classification of objects must be made consistent and systematic, in 

 order to be scientific ; we must discover marks and characters, pro- 

 perties and conditions, which are constant in their occurrence and 

 relations; we must form our classes, we must impose our names, 

 according to such marks. We can thus, and thus alone, arrive at thai 

 precise, certain, and systematic knowledge, which we seek ; that is, at 

 science. The object, then, of the classificatory sciences is to obtain 

 FIXED CHARACTERS of the kinds of things; and the criterion of the 

 fitness of names is, that THEY MAKE GENERAL PROPOSITIONS POSSIBLE. 

 I proceed to review the progress of certain sciences on these princi- 

 ples, and first, though briefly, the science of Mineralogy. 



Sect. 2. Of Mineralogy as the Analytico-classificatory Science. 



MINERALOGY, as it has hitherto been cultivated, is, as I have already 

 said, an imperfect representative of the department of human know- 

 ledge to which it belongs. The attempts at the science have gene- 

 rally been made by collecting various kinds of information respecting 

 mineral bodies ; but the science which we require is a complete and 

 consistent classified system of all inorganic bodies. For chemistry 

 proceeds upon the principle that the constitution of a body invariably 

 determines its properties ; and, consequently, its kind : but we cannot 

 apply this principle, except we can speak with precision of the kind 

 of a body, as well as of its composition. We cannot attach any sense 

 to the assertion, that " soda or baryta has a metal for its base," except 

 we know what a metal is, or at least what properties it implies. It 

 may not be, indeed it is not, possible, to define the kinds of bodies by 

 words only ; but the classification must proceed by some constant and 

 generally applicable process ; and the knowledge which has reference 

 to the classification will be precise as far as this process is precise, and 

 vague as far as this is vague. 



There must be, then, as a necessary supplement to Chemistry, a 

 Science of those properties of bodies by which we divide them into 

 kinds. Mineralogy is the branch of knowledge which has discharged the 

 office of such a science, so far as it has been discharged ; and, indeed, 

 Mineralogy has been gradually approaching to a clear consciousness 

 of her real place, and of her whole task ; I shall give the history of 

 some of the advances which have thus been made. They are, principally, 



