Elements of Mineralogy. 

 gravity, isfoluble in the fame acids, and witfl 

 the fame phenomena ; but it is much mo're 

 fufible, very brittle, eafily fcorified and vo- 

 latilized, and refufes to mix with lead wheii 

 ill fufiofu It were to be wiftied it was better 

 examined. 



CHAP. XX, 



Reflexions on the nature of Cobalt ^ Nickel^ and 

 Manganefe. 



I. The principal reafon why any fimple 

 fubftances are reckoned fpecifically different 

 from each other, is their manifefting pro- 

 perties permanently different iri the fame cir- 

 cumftances, and every fubftance muft be 

 deemed fimple, until it can be refolved into* 

 different principles, or formed out of them, 

 fevery other indication is at beft a furmife 

 grounded <3n mere poffibility, but deftitute 

 of probability, and therefore inadmiffable iri 

 any exact fcientifical fyftem i upon this foun- 

 dation moft chymifts and mineralogifls have 

 admitted the abovementioned fubftances to a 

 diftincT: rank among femi-metals* Yet as 

 fofne othef s deferVedly of great note, namely, 

 Mr. Pabft, Mr. Monnet, and Romt de Lifle 

 have afferted, that all, or fome or other of thefe 

 femi-met&ls, are either modifications of iron, 

 or compounds of fome fort; I prefume it will 

 not be amifs before I conclude this treatife* toi 



Hate 



