614 poisons: tiieir effects and detection. [§§780,781. 
Several lamentable accidents have happened through mistaking the 
sulphide of antimony for oxide of manganese, and using it with potassic 
chlorate for the production of oxygen. The addition of a drop of 
hydrochloric acid, it is scarcely necessary to say, will distinguish 
between the two. 
Antimony is frequently estimated as sulphide. An amorphous 
tersulphide of mercury, containing a small admixture of antimonious 
oxide and sulphide of potassium, is known under the name of Kermes 
mineral, and has been employed in the vulcanising of india-rubber. 
Prepared in this way, the latter may be used for various purposes, and 
thus become a source of danger. It behoves the analyst, therefore, in 
searching for antimony, to take special care not to use any india-rubber 
fittings which might contain the preparation. 
A pentasulphide of antimony (from the decomposition of Schlippe’s 
salt [Na 3 Sb 6 S 4 + 9H 2 0], when heated with an acid) is used in calico- 
printing. 
§ 780. Tartarated Antimony, Tartrate of Potash and Antimony, 
or Tartar Emetic is, in a medico-legal sense, the most important of 
the antimonial salts. Its formula is K8bC 4 H 4 0 7 H 2 0, and 100 parts, 
theoretically, should contain 35-2 per cent, of metallic antimony. The 
B.P. gives a method of estimation of tartar emetic not free from error, 
and Professor Dunstan has proposed the following :—Dissolve 03 grm. 
of tartar emetic in 80 c.c. of water, add to this 10 c.c. of a 5 per cent, 
solution of sodium bicarbonate, and immediately titrate with a decinormal 
solution of iodine, using starch as an indicator. One c.c. of N/10 iodine = 
0-0166 grm. tartar emetic ; therefore, if pure, the quantity used by 
Q’3 grm. should be 18 c.c. Tartar emetic occurs in commerce in 
colourless, transparent, rhombic, octahedral crystals, slightly efflorescing 
in dry air. 
A crystal, placed in the subliming cell (p. 262), decrepitates at 
193*3° (380° F.), sublimes at 248-8° (480° F.) very slowly and 
scantily, and chars at a still higher temperature, 287-7° (550° F.). 
On evaporating a few drops of a solution of tartar emetic, and 
examining the residue by the microscope, the crystals are either 
tetrahedra, cubes, or branched figures. 100 parts of cold water dis¬ 
solve 5 of tartar emetic, whilst the same quantity of boiling water 
dissolves ten times as much, viz. 50. The watery solution decom¬ 
poses readily with the formation of algse; it gives no precipitate 
with ferrocyanide of potassium, chloride of barium, or nitrate of silver, 
unless concentrated. 
§ 781. Metantimonic Acid, so familiar to the practical chemist from 
its insoluble sodium salt, is technically applied in the painting of glass, 
porcelain, and enamels ; and in an impure condition, as antimony ash, to 
the glazing of earthenware. 
