A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...

THE ANTIMONY PREPARATIONS AND THEIR USES. 159
should the gas be accompanied by a large proportion of steam. The
chloride of antimony thus obtained is diluted with water to 25° Be.
" The two solutions of antimony and of hyposulphite being prepared,
we proceed as follows:—We pour into a stoneware vessel 4 litres
of chloride of antimony, 6 litres of water, and 10 litres of hyposulphite
of soda. The precipitate caused by the water is rapidly
dissolved in the cold by the hyposulphite. The vessel is then placed
in a hot-water bath, where the temperature of the mixture is
gradually raised. At about 30° C. the precipitate of sulphite begins
to form; it is orange-yellow at first, and becomes darker afterwards.
At 55° C. the vessel is removed from the water-bath and the precipitate
is allowed to settle, which it does rapidly. The motherliquors
are decanted, and the deposit is washed, first with water
holding -j^- of HC1, and afterwards with ordinary water. Lastly, the
precipitate is collected upon a filter and dried. The wet vermilion
of antimony is of an exceedingly bright red colour; after drying, it
loses part of its brightness. This pigment may be prepared in the
cold, but the product is finer and more constant if we operate in the
manner just described.
" Being certain to reproduce my new sulphide whenever it is
desired, I have undertaken its analysis. But as the determination
of the antimony is very difficult, and as there is no known method
sufficiently accurate for the purpose, I have determined the sulphur
and calculated the antimony by difference. It has also been necessary
to determine the proportion of water. Moreover, I have compared
the oiange-yellow sulphide with my own, and the result is:—
0*668 of orange-yellow sulphide loses 0 # 038 at 200° C.
0*808 of red sulphide loses 0*009 at 200° C.
"This proves that the vermilion of antimony is an anhydrous substance,
and that the above shown is due to imperfect drying.
" There now remains to prove by analysis that the vermilion of
antimony differs from the orange-yellow sulphide by only one
equivalent of water. This explains the new properties of the red
sulphide. I have found by analysis:—
Water 1*1
Sulphur 26*7
Antimony (by difference) . . .72-2
100-0
which composition proves that the equivalents of sulphur and antimony
are in the ratio 3:1."