148 
MANUFACTURE OF ACETATE OF SODA. 
must depend entirely upon the size of the crystals required. Should 
they be wanted larger than can be obtained in the above, the leads 
must be deeper, packed in sawdust, and allowed to stand a longer 
time. When the crystallization is complete, the mother-liquor 
must be taken from the crystals and emptied into the dissolving 
lead, and with the addition of two or three times its weight of 
water, used in dissolving fresh fused salt from the torrifying pans ; 
the crystal must then be cut out of the leads, and thrown into a 
conical-shaped drainer and well washed. The liquor caught from 
the drainer must be put into the dissolving lead also. The crys- 
tals are now to be removed from the drainer to the drying-stove, 
where, after having been a few hours on the shelves, they should 
be packed in casks, and the sooner they are sold or used the better, 
as by keeping a loss of weight is sustained by deliquescence. 
The following process has been employed in the Cornbrook Works, 
near Manchester, under the able superintendence of Mr. A. P. 
Halliday :— 
The rectified pyrolignous acid is saturated with lime, and the 
resulting solution of acetate of lime boiled down to specific gravity 
1.200. This solution is now dosed with sulphate of soda, obtained 
from the decomposition of acetate of soda by sulphuric acid, until 
their is no further precipitate; sulphate of lime then falls down, 
and acetate of soda remains in solution. The sulphate of lime is 
thrown upon stone filters, twelve ft. by six ft. and washed with 
water until the solution comes off so weak as not to be sufficient 
to afford remuneration for the expense of labor, time, and fuel. 
The solution of acetate of soda along with the washings of the 
sulphate of lime, is next boiled down in iron pots, six ft. long, by 
three ft. deep, cold set, until its specific gravity reaches 1.300. 
During the evaporation, the excess of sulphate of soda is fished up 
in ladles, pierced full of holes, and the salt laid on drainers sus- 
pended over the pot from which it had been raised. The solution 
at 1.300 specific gravity, is allowed to settle over night and then 
drawn off to crystallize. The crystals are dissolved, in dilute py- 
rolignous acid, and the solution at 1.270 drawn off after settling 
for a fresh crystallization ; the crystals are again dissolved, drawn 
off at specific gravity 1.500, dried and fused. The solution of 
fused salt is evaporated down, crystallized, and the crystals again 
dried and fused, and the fused salt allowed to flow out on an iron 
