396 Introduction to the Study of Mineralogy. 



ments, which we might be justified in regarding as belong- 

 ing to so many species distinctly circumscribed * : so that, in 

 order to distribute them afterwards in a well arranged me- 

 thod, it would be sufficient to have the analysis of one single 

 body taken in each. 



From this we may conceive in what sense to understand 

 what I have above hinted at, namely, that to chemistry be- 

 longs the determination of species. It would perhaps be 

 more correct to say that it completes this determination by 

 making us acquainted with the principal molecules, of which 

 the integrant molecules are the assemblages. Already it is 

 easy to perceive (and the subsequent part of the work will 

 contain several examples) how interesting it is that the in- 

 quiries relative to these two kinds of molecules should con- 

 spire towards one common object ; that the chemist and the 

 mineralogist should mutually enlighten each other by their 

 labours; and that goniometry, which furnishes data for sub- 

 mitting crystalline forms to calculation, should be associated 

 with the scales that weigh the products of analysis. 



The principal object of this Treatise is to detail and de- 

 velop a method founded upon certain principles, and which 

 serves as a kind of survey to all the information presented 

 by mineralogy, assisted by the different sciences which can 

 go hand in hand with it in one and the same line. It is 

 calculated to bring all the minerals known under one and 

 the same point of view, in order to compare them with each 

 other, to study their characters, and to investigate alter- 

 nately by experiment and theory the different phaenomena of 

 which they are susceptible. Every thing which can procure 

 the observer the double advantage of being at once guided 

 and enlightened during his progress will be employed ; and 



* These assortments would not be limited to crystals properly so called : 

 ye might also include lamellated masses, or even those which caimot be sub- 

 jected to a mechanical division : for these last have frequently, when com- 

 pared with analogous crystallized substances, a relation, in point of position 

 and aspect, which ascertains them to belong to the same species: and thus 

 these masses, insignificant in themselves, may be determined, at least inter- 

 mediately, by the assistance of crystals which serve them in seme measure as 

 interpreters. 



this 



