ON KERMES MINERAL. 
57 
from oxide, forms, when pulverised, a black powder, while if 
it contains oxide, it is more or less disposed to assume a red- 
dish or brownish tint. 
If kermes be heated for sometime in hydrogen gas, the sul- 
phuret of antimony, consisting of SbS 3 , is reduced to metallic 
antimony, but the salt of sulphur does not undergo the least 
change, and any antimony which it may contain, united with 
a greater amount of sulphur, is not brought to a lower state by 
losing its sulphur. Only a small quantity of water is libe- 
rated with which the salt of sulphur was combined. It is usu- 
ally considered that this water disengaged on treating kermes 
with hydrogen, is derived from the reduction of the oxide 
contained in the kermes. 
The kermes, as a result of what we have said, cannot be 
identical with the mineral Rothspiesglanzers* nor as an 
analogous compound, for this latter is, according to my re- 
searches, a compound of oxide of antimony and sulphuret 
Sb + 2SbS 3 . 
2. Kermes prepared by fusing sulphuret of antimony 
with an alkaline carbonate. This is the ordinary officinal 
kermes of the Pharmacopoeias, which prescribe this mode oi 
preparation. 
On fusing the sulphuret of antimony with an alkaline car- 
bonate, it is known that a large amount of metallic antimony 
separates. The common opinion with regard to this separation 
is, that the oxide of antimony, by an elevated temperature and 
the presence of an alkali, is resolved into the metal and an- 
timonic acid. 
When the kermes prepared in this way, after many wash- 
ings, and^while yet moist, is boiled with tartar and water, there 
is obtained from the filtered solution, by means of hydrosul- 
phuric acid gas, a voluminous precipitate of sulphuret of anti- 
mony. This effect does not take place with a kermes prepared 
by boiling in a solution of alkaline carbonate ; it contains no 
* Red antimony of Saxony and Hungary. Native kermes, Delisle ; Hy- 
drosu/phuret of antimony, Hauy. 
VOL. VII. NO. I. 8 
