PURE BARTTI€ WATER AND SALTS OF BARTTES. 
233 
ART. LXVII. — ON THE PREPARATION OF PURE JBARYTIC 
WATER AND PURE SALTS OF BARYTES. 
By H. Wackenroder. 
When 240 grms. of finely-ground heavy spar are inti- 
mately mixed with 60 grms. of colophony and 20 grms. of 
powdered charcoal, and the mixture heated to redness in a 
covered crucible nearly filled with it, the sulphate of baryta 
is readily and advantageously decomposed. The ignition 
may be affected in an ordinary furnace of sheet iron 
provided with a dome, and is continued from half to 
three-quarters of an hour. When meal or sugar is 
employed for the reduction, and a very strong heat, ap- 
approaching nearly to white heat, employed, soluble mono- 
sulphuret of barium is scarcely formed. The ignited mass 
is loose, yellowish-grey or reddish, and yields, on boiling 
with water in a porcelain dish, a saturated solution of ba- 
ryta and bisulphuret of barium, together with some hypo- 
sulphite of baryta. The alkaline liquid is consequently 
yellowish, and deposits on suitable concentration a tolera- 
ble quantity of hydrate of baryta and some sulphuret of ba- 
rium ; the residue, insoluble in hot water, consists of unde- 
composed heavy spar with some coal, metallic sulphurets 
and the earthy substances mixed with the mineral and the 
coal. To prepare any salt of baryta, the sulphuret of 
barium is repeatedly exhausted with boiling rain-water, 
and the baryta precipitated by carbonate of soda. With 
very dilute nitric acid the solution readily yields perfectly 
pure nitrate of baryta, as this salt may be easily separated 
by crystallization from the less-easily crystallizing salts. 
Chemically-pure chloride of barium is most readily obtained. 
For this purpose, the solution is mixed with dilute crude 
muriatic acid until the liquid indicates the presence of a 
slight excess of acid ; the precipitate of sulphur, sulphate of 
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