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56 ON KERMES MINERAL. 
1. Kermes obtained by boiling sulphuret of antimony in 
a solution of an alkaline carbonate. When sulphuret of an- 
timony is boiled in a solution of an alkaline carbonate, there is 
formed a sulphuret of the alkaline metal, holding in solution 
sulphuret of antimony, a salt of sulphur, and oxide of antimo- 
ny. The sulphuret of the alkaline metal dissolves, by aid of 
heat, much sulphuret of antimony, nearly all of which, on 
cooling, it abandons under the form of kermes, but a very 
small portion remaining in solution. The oxide of antimony 
formed, dissolves completely when sufficient of the alkaline 
carbonate is used ; otherwise, a part precipitates, on cooling, 
along with the kermes; especially if this latter is allowed to re- 
main sometime in contact with the liquid from which it was 
deposited. Under all circumstances this oxide is mechanically 
mixed, and not chemically combined with the kermes. Of this 
any one may be readily satisfied by microscopical examination 
of this product. True kermes appears under the form of red 
or reddish brown grains, and if it contains oxide of a,ntimony, 
there is very clearly to be perceived, more or less abundant 
crystals, which for the most part are six-sided prisms, but 
which often appear under the form of fine needles ; these 
are entirely absent when the antimony is dissolved in an ex- 
cess of alkaline carbonate, under which circumstances there is 
a more considerable production of kermes. 
The oxide of antimony, which may contaminate the kermes, 
is not combined with the alkali, but by analysis of the kermes, 
the alkali may always be obtained under the form of a sulphur 
salt. It contains a small quantity of sulphuret of potassium or 
sodium, as M. Berzelius has long since demonstrated ; forming 
a salt of sulphur with the highest degree of sulphuration of an- 
timony, SbS 3 . It cannot be entirely separated from the 
kermes by washing. The quantity obtained with the kermes 
made by boiling sulphuret of antimony in a solution of an al- 
kaline carbonate, is in reality very small. 
The presence of oxide of antimony in kermes is easily re- 
cognisable without the use of the microscope, by fusion in an 
atmosphere of carbonic acid gas. The fused kermes, when free 
