, 3 Mr. Wedgwood’s Analyp of a 
There is one circumftance in Mr. Scheele's experiments, 
which, though omitted by thofe who have given abftrafts of 
them, may deferve, on the prefer* occaficn, to be more parti- 
cularly noticed. He reduced the molybdaena into fine powder, 
and poured upon it concentrated nitrous ac.d: “ mixture 
he fays, was hardly lukewarm in the retort, when it pafled all 
“ together into the recipient with great heat ; an t was or 
this reafoti that he afterwards ufed diluted acid. 1 refum.ng 
that this violent aftion of the concentrated nitrous acid m.ght 
afford a decifive criterion of molybdaena, I a t e ac - re l 
duum, after five or fix abftraftions of the diluted aci , groun 
fine upon a levigating glafs, and returned into the retort, with 
fix times its weight of fmoking fpirit of mtre. The heat was 
increafed cautioufly far beyond lukewarm, but no comrootioi 
could be perceived, except the explofions already mentioned, 
which always took place when the mixture was near boilmg. 
The diftillation was continued to drynefs, and repealed fie 
times with the fmoking acid ; but the mineral remained juft 
black as it was at firft. , 
Now, as Scheele’s rholybdaena is (lowly decompofed by the 
diluted nitrous acid, and rapidly afled upon by the , concen- 
trated acid, while the black part of this mmeral obft.na tely 
refifts both, I think we cannot hefitate to conclu e, - 
Mack fubftance is not Scheele’s molybdarna. There are feme 
other circnmftances which confirm this concluf.on, although, 
finely, they would not, perhaps, be of much werght 
ordering the gLt proportion of other matter tee m.xe 
with the black. The principal of thefe c.rcumtac a , that 
vields no flowers before a blowpipe, and that its p 
' feem to have no flexibility or elafticity, the only dtfficu y^ 
