on the Composition of James’s Powder. 3 65 
Though it is probable, from this experiment, that there is 
an affinity between antimonial calx and vitriolic felenite, it is 
plain that the compound is very different from James’s Powder. 
The next experiment with chalk and antimony, which Dr. 
Blagden had the goodnefs to fuggeft, would lead to feveral 
concluftons, but I fliall only take notice of the compofition 
produced. 
Exp. xt. 1200 grains of antimony were mixed with 800 
grains of well wafhed, dried, and pulverized chalk, and cal- 
cined as in making Lile’s Powder. In lefs than an hour the 
fmell of fulphur difappeared ; after which the mixture was 
calcined half an hour longer. It afforded a lighter clay- 
coloured powder than the calcination of antimony with boue- 
afhes; and weighed 1800 grains. By expofure to ico° of fire 
this powder changed to a dirty white colour. On examination, 
in Bead of aerated lime or chalk, there was found vitriolic fele- 
nite, part of which was probably combined with the antimo- 
nial calx; for, by means of boiling water repeatedly applied 
till the lixivium did not become turbid with muriated ba- 
rytes nor acid of fugar, I could only obtain 1 2 per cent, of 
vitriolic felenite, mixed with a little antimonial calx ; but by 
means of nitrous acid I feparated 45 per cent, of this felenite, 
with fcarcely any antimonial calx in it. The refiduum, after 
this folution in nitrous acid, was calx of antimony with a little 
vitriolic felenite feemingly vitrified. Accordingly the compo- 
fition may be Bated to confift of 1000 parts of antimonial calx 
and 950 parts of vitriolic felenite which I infer from the quan- 
tity of felenite diflolved by the nitrous acid, and eflimated to 
remain united to the calx ; and from the following calcula- 
tion of the proportion of thefe two ingredients formed in the 
experiment. 
2 
Anti- 
