Mineralogy, according to the Principles of Professor MOHS. 305 



from having observed the whole series of compound varieties, 

 we infer that the last is exactly the same thing as the first, and 

 only distinguished from it by the size of the individuals. It is 

 often the case that compound minerals again consist of com- 

 pound varieties, variously aggregated : thus Peastone is a granu- 

 lar composition of globular particles ; each of them consists of 

 concentric layers, parallel to their surface, and each of these on- 

 ly, if further examined, shews the disposition of delicate fibrous 

 individuals, in- a direction corresponding to that of the radii of a 

 sphere. Compound minerals are objects of a natural-historical 

 consideration, only in so far as they consist of individuals; in the 

 same way as herds of cattle or forests are considered in zoology 

 and botany, only because they consist of individuals, the more 

 peculiar object of these sciences. 



Various opinions have been current among mineralogists as 

 to the exact meaning of the term individual in mineralogy. 

 Some extended the idea of individuality to every specimen or 

 fragment of a mineral whatever. Others maintained that per- 

 fect crystals only could be considered as individuals. According 

 to the opinion of some, there was only one individual, the spe- 

 cies itself; while others considered the mountain-mass from 

 which the specimen had been detached, as the only true indivi- 

 dual. Many denied the existence of individuals in mineralogy 

 altogether, or fixed this idea upon the ultimate particles of mat- 

 ter, in which the mechanical connection cannot be resolved, 

 without, at the same time, destroying the chemical mixture. 



According to Professor MOHS, perfect crystals are individuals, 

 but not the only ones ; every product of the power of crystalli- 

 sation, consisting of continuous and homogeneous matter, of a 

 regular or irregular form, large or small, every component par- 

 ticle of granular limestone, every fibre of hematite, being like- 

 wise comprehended within that idea. 



The connection among certain individuals, in preference to 



Qq 2 



