Reflections on some Mineraloglcal Systems. 299 



ble 5 or, tljey might be so blended together in iheir origin, 

 that in the mass which would be produced, it would be im- 

 possible to discover one simple species whose molecules 

 had contributed to form it. 



TRUE PRINCIPLES OP FORMING MINERALOGICAL SPECIES. 



In the mineral kingdom, therefore, we must admit the 

 following four conditions, arising from circumstances which 

 have presided at the formation of minerals : 



] st. Simple minerals whose molecule we are able to dis- 

 cover : 



2d. Simple minerals whose molecule -eludes our re- 

 searches : 



3d. Compound minerals in which the simple component 

 minerals are discernible: 



4th. Compound minerals in which we cannot distinguish 

 the simple components. 



Of these four conditions there is but the first which gives 

 the species with strictness, and which truly appertains to 

 science; but the others belong to nature, and must not be 

 excluded from the method of classification. If, then, we 

 find in any mineral, characters sufficiently marked to esta- 

 blish a well-founded opinion that it is of the same species 

 with some one of the first section, we refer it by analogy to 

 this, and consider it as belonging to the same species. 



What is carbonated lime? — It is a mineral composed of 

 0*55 lime, and 0*45 carbonic acid, and which has for its 

 molecule an obtuse rhomboid, whose great angle is 101* 

 32' 13". Here is carbonated lime defined ; and it is evi- 

 dent that in our principles a mineral which has these pro- 

 pertiesnecessarily belongs to this species. What is com- 

 pact carbonated lime ? — It is a mineral whose chemical com- 

 position makes us presume with the utmost likelihood that 

 it is of the same species as crystallized carbonated lime, 

 and that it differs only in the circumstances under which it 

 has been formed, not having permitted the symmetrical ar- 

 rangement of its molecules, so that one might extract from 

 the mass the solid, which it represent*;. Here the type is 

 but presumed ; and it is only after strong proof from ana- 

 logy that we resolve to class in the species of carbonated 

 lime, a substance which cannot be proved strictly to belong 

 to it. 



In granite, gneiss, and porphyry wc distinguish the pieces 

 of simple minerals or which they are composed. They appear 

 to have enjoyed in their formation fill the circumstauces 

 which could favour the union of the molecules of the same 



species 



