234 PURE BARYTIC WATER AND SALTS OF BARTTES. 1 
baryta, and at times also sulphuret of arsenic, is separated 
by filtration, and the liquid evaporated until but little mo- 
ther-ley is left, which contains chloride of calcium, chloride 
of strontium and perchloride of iron. The dried chloride of 
barium is readily freed from adhering muriatic acid and 
perchloride of iron by exposing to a faint red heat, dissolv- 
ing in water and filtering. About one-third the amount of 
the heavy spar employed is obtained ; if the whole of the 
heavy spar had been reduced, a much larger quantity of 
chloride of barium would naturally be obtained, but the 
loss of heavy spar, which however may be employed in 
subsequent operations, is fully compensated for by the lesser 
amount of labour required. 
To obtain perfectly pure barytic water, the sulphuret of 
barium is exhausted with as little boiling water as possible, 
and the yellow liquid allowed to cool in a tall covered glass. 
Upon this the liquid is separated as perfectly as possible 
from the crystallized hydrate of baryta ; the latter then dis- 
solved in water, and boiled in a porcelain dish with pure 
hydrated oxide of copper until a sample of the liquid yields 
with solution of acetate of lead a white precipitate. If, after 
boiling the liquid for some time, it is found to contain some 
copper, it is filtered, and a small quantity of hydrated oxide 
of silver, or carbonate recently precipitated from the nitrate 
of silver by pure caustic or carbonate of soda, added to it. 
On digestion, every trace of hyposulphurous acid and oxide 
of copper is removed, and sulphuret of silver formed.—- 
Chem, Gaz.from %flrchiv. der Pharrn, 
