1 90 JQn O'ptallographij, 



giiisheil from ihcm. The second advantage is, that JiFter 

 >\'e have been exorcised in making applications from the 

 iD&thocl to a certain number of objects already known, we 

 may attain a knowledge even of that which would be new 

 to lis, by consulting succes>ively the characters which ac» 

 company each division, and by making nse of the method 

 to inqviire into the subject, and to learn from the object it- 

 self the place which it occupies in the method. 



The series of divisions and sul)clivisions in n)ineralogicaf 

 distributions is nearly the same as in those which reeard 

 organic bodies. This .Series, taken by descending from 

 generals to part icularsj gives ihc following gradation: 

 classes, orders, genera,- 'species, .varieties. But there is a 

 sensible difl'erenee relative to ihe methods used in these 

 two departments of science, relative to the manner in which 

 we consider objects, or to the choice of the method^'Cim- 

 ployed to classify and characterize these objects. ' 



Thus, in botany, we cwW species the succession of plants 

 which, reproduce each other. In ntinefalogy, there Ts nei- 

 ther reproduction nor species, if xv£ take this i^xiw in «i 

 rigorous acceptation. There is nothing, however, to hinder 

 us fron) follou ing the example of Linnaeus, Bervj^man, and 

 several other celebrated naturalistSj in applying the word 

 species in a wider sense, to an .assemblage of inorganic 

 beings which have a common basis, and ihe differences of 

 which ought to be regarded as purely accidental. 



But this leads us to an important question, to which it 

 does not seen) that sufficient attention has hitherto been 

 paid. In what consists in the present case the type of the 

 species; — and when are we justified in regarding several mi- 

 nerals as belonging to one and the sanie species* ? It 

 seems at first view as if chemical coiDposilion was the basis 

 of this union ; so that the true notion of the species con- 

 sists in conceiving an assemblage of minerals formed of 

 the san)e principles united to each other according to the 

 same laws. But we shall see how much this idea is sus- 

 ceptible of restriction, and to what point even we should 

 wander from our object, in a multitude of circumstances, 

 on taking it for our guide, in assembling of varieties which 

 ought to bear one and the same specitic name. 



* I shall by and by recur to the r<?a9ons which induced me to apply thi* 

 word, rather ihaa that of ,t,'e,'i//.<r, to the diifercnt objects which in the language 

 received among naturalists have a common" name, such as lopuz, ememldy 

 gnniet, &c., or, if an acidifirons subetance is alluded to, the term carbonated 

 lime, sid/>hate'l banjtcs, Sec. It is sulVicicnt for my purpose at present to 

 point out such of the divisions and subdivisions of l-he uitthod to -which 1 

 give the denociiuation sy.cdes. 



In 



