292 Reflections on some Miner alogical Systems. 



Such ideas will not be very generally received among those 

 who have studied this science, nor even by those who are 

 most disposed to discover its imperfections. 



INCONSISTENCY - AND UNCERTAINTY OF THE WEKNERIAN 

 PLAN OF SPECIFICATION. 



We now perceive the difficulty of reconciling the im- 

 mense number of principles which this system has founded, 

 and the contradictions which the minerals themselves must 

 render unavoidable in whoever adopts them as a basis. Let 

 us examine, in a few examples, if their celebrated author 

 has been able to draw any uniform laws from them. Five 

 things are to be known, viz. 



1st. If all the minerals which have essentially the same 

 chemical composition are ranged in the same species. 



£dly. If all those which have an essential difference in 

 their chemical composition are placed in different species. 



3dly. If all the minerals which differ in more than three 

 specific characters, whatever may be the number of those 

 which they have in common, belong to different species. 



4thly. If all those which do not differ in more than three 

 different characters, are ranged in the same species. And, 



5thly. If the minerals are always divided into genera, spe- 

 cies, and varieties, according to their difference ; that is to 

 say, if those placed in separate genera always differ more 

 from each other, than those which belong to species, or to 

 different varieties, &c. ^ 



The relative condition in the 1st Art. is violated in the 

 most striking manner by Werner's zirconian genus, which is 

 divided into three species, and to which chemical analysis 

 gives the same results. In corundum and adamantine spar 

 we have two species * with the same chemical composition : 

 it is the same in appatite, asparagus-stone and phospholite. 

 Gypsum and fraueneis (selenite) are in a similar state ; and 

 carbonated lime presents us with no less than the alarm- 

 ing number of 14 species, which contain eight subspecies 

 and six varieties. 



In the 2d Art. we have beryl which contains glucine 

 earth, and schorlous beryl which contains none, but which 

 has instead of it fluoric acid. These minerals, without any 



* Here the Wernerians make a distinction without a difference: corun- 

 dum is used as synonymous with the adamantine spar of Kirwan, and im- 

 perfect corundum of Orcville and Bournon; while diamond spar is made a 

 distinct species, although forming only tin.- subspecies corindun harmophane of 

 Haiiy, or adamantine corundum of Brogniart. — Trans. 



affinity 



