'Examination of various Ores. 5 3 5 
experiments, we made the following one, which Teems 
conclufive. 
Half an ounce of filver was precipitated from nitrous 
acid by copper, in fmall flaky cryftals as ufual ; being 
waflied and dried, it was mixed with the fame weight of 
fulphur, and put into a crucible, over which another was 
placed fo as to cover it, and the two crucibles were luted 
together, leaving a fmall aperture for the efcape of va- 
pour, but not fo as to admit air for the inflammation of 
the fulphur. Thefe being put into the fire, as foon as 
they were heated red-hot, the fulphur in part efcaped 
through the fmall hole, and as it pafled through 
burnt with a blue flame. The fire was increafed to a 
fufficient degree to melt the mafs within; in the mean 
time the blue flame difappeared, which fhe wed that no 
more fulphur efcaped. 
After we had applied heat enough, as was fuppofed, 
to melt the mafs, the crucibles were removed from the 
fire, and being feparated when cold, a regular button- 
like mafs was found in the crucible, of a dark lead colour 
both without and within, brittle, and ftreaked on the in- 
fide, bearing to be cut with a knife, exadlly like the vi- 
treous ore, which it in every way refembled. The whole 
mafs gained twenty grains or one twelfth in weight, 
which may be confidered as the true weight of the ful- 
4 A 2 ' phur 
