on the Compojltion of James’s Powder. g 55 
was eafily detached from the vefiel, was found covered with a 
yellow vitreous coat over the whole furface of it that had been 
tn contact with the crucible. I11 the white folid, on breaking 
it, many argentine fpicula were feen. The pyrometer ufed in 
all thefe experiments indicated yi°. 
(c) 1500 grains of the fame parcel, Exp. 3. were expofed 
in an open crucible to the fire of a melting furnace ; no 
fumes arofe till the crucible began to be almoft white hot. 
After inverting another crucible, with a fmall hole in its bottom, 
the fumes continued to afcend at times through the aperture 
for a quarter of an hour. The crucible was then taken out of 
the fire, and on cooling a whitijh powder was found, but no 
glazing, and the pyrometer indicated 28°. On again expofing 
this crucible with one inverted over it in the melting furnace, 
but to a greater degree of fire, ftill more fumes arofe ; but, on 
cooling, the charge was ftill in the ftate of a powder, though 
whiter than before; and the infide of the inverted crucible was 
covered with filvery particles, and the hole of it was furrounded 
with argentine fpicula , in a ftellated form. The pyrometer 
indicated 39 0 . On reducing a little of this powder to a greater 
degree of finenefs, it was as white as James’s Powder, with a 
yellowifli caft like it, but inferior in whitenefs to a fpecimen of 
Pulvis antimonialis. This crucible, containing its charge, with 
a cover clofely luted on it, was put again into the fire, which 
was raifed much higher than before ; and, after being expofed 
in it twenty minutes, the powder in the crucible became a 
loofely cohering folid, as white as fnow, with a vitreous yellow- 
coat, as before obferved ; the infide of the crucible was glazed 
and covered with fpicula. The pyrometer- piece in the middle 
of the powder was alfo covered with a yellow coat, but not 
A a a 2 glazed. 
