240 A SYSTEM OF 



have not fufficient experience, form to themfelves 

 falfe notions of the whole compound, and of each 

 part contained in it : For which reafon they chuie 

 rather to retain that definition of the Kupfernickel 

 which has received its fanction from the carliefl 

 authors, than to admit the conclufion to which 

 Mr Cronftedt's experiments feem to lead. 



For my own part, I have found myfelf obliged to 

 follow the opinion of the latter, partly becaufe I 

 am tired with thofe common epithets given to un- 

 known bodies •, fuch as* wild, refratlory, rapacious^ 

 crfenical, irreducible, metallic earth, &c. &c. which 

 regard the effect alone and not its caufe ; and part- 

 ly becaufe I have not, befides the nickel, found 

 any metal or metallic compofition, which 



i. Becomes green when calcined. 



2. Yields a vitriol, whole colcothar alio be- 

 comes green in the fire. 



3. So eafily unites with fulpliur, and forms 

 with it a regule of fuch a peculiar nature, as the 

 nickel does in this circumftance -, and that 



4. Does not unite with filver, but only adheres 

 or flicks clofe to it, when they have been melted 

 together. ' 



The nickel not having yet been found free from 

 cobalt and iron, is the reafon why it was not dis- 

 covered. This was the cafe alio with the cobalt. 

 Platinadelpintoperhaps,inthe fame manner, might 

 for a long time have been mixed in the gold, at 

 certain places, where it is laid to be naturally paler 

 than any where elfe in the world. But the cxiftence 

 of fuch things cannot any longer be denied, fince 

 the method is difcovered to get them feparate, 

 and free from heterogeneous fubflances. It indeed 

 would be the fame thing, as if in a country where 

 filver is never found but in the potter's lead ore, 

 any perfon fliould deny the exigence of either of 



thefe 



