32 



the same minerals are found in many different 

 rocks in many varieties of combination. 



These remarks have already been sufficiently 

 illustrated in the former part of this chapter, in 

 treating of the several bases that may be assumed 

 as the foundation of a mineralogical arrangement. 

 The question of a nomenclature necessarily rests 

 on the same grounds. Any attempt to combine 

 these two circumstances, namely, the composition 

 and the structure, is productive of still greater 

 confusion ; nor does it appear possible to adopt 

 any natural system of nomenclature derived from 

 mineralogical principles. 



If an attempt be made, on the other hand, to 

 avoid these difficulties by the adoption of un- 

 meaning terms for all the varieties, (or rather 

 species, as they would in this case be esteemed,) 

 in the same manner as has been done with regard 

 to many of the principal rocks, a nomenclature 

 would, in becoming arbitrary, become useless for 

 its professed purpose of displaying the mineralo- 

 gical affinities of the rocks arranged under it. 



