A SY$TEM OF 
.240 
have not fuSicient experience, form to themfelvei 
falfe notions of the whole compound, and of each 
part contained in it : For which reafort, they chufe 
rather to retain that definition of the Kupfernickel 
which has received its fandion' from the earlieft 
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^ refraBory^ rapacious^ 
nrfenicat^ irreducible ^ raetallic earthy &c. &^c. which 
regard the effedl alone and not its caufe ; and part- 
ly becaufe I have not, befides the nickel, found 
any metal or metallic compofition, which 
1. Becomes green when calcined. 
2. Yields a vitriol, whofe cblcothar alfo be- 
comes green in the fire. 
3. So eafily unites with fulphur, and forms 
with it a regule of fuch a peculiar nature, as the 
nickel does in this circumftance ^ ^rld 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 v/hy it was not dif- 
covered. This was the cafe alfo with the cobalt. 
Platina del pinto perhaps, in the fame manner, might 
for a long time have been mixed in the gold, at 
certain places, where it is ftid to be naturally paler 
than any where elfe in the world. But the exiflence 
of fuch things cannot any longer be denied, fmce 
the method is dlfcovered to get them fepaiate, 
and free from heterogeneous fubilances. It indeed 
would be the fame thing, as if in a country where 
fiiver is never found but in the potter's lead ore, 
any perfon fiiould deny the exiflence of either of 
thefe 
