52 
MANUFACTURE OF ACETATE OF LIME. 
filtration of the crude acid through layers of saw-dust and gravel 
before it is neutralized with lime, and that the solution of the ace- 
tate having been brought to boil, should be filtered or allowed to 
stand for thirty-six or forty-eight hours ; also that at two subsequent 
periods of the operation the solution of lime salt should be drawn off 
from the evaporating pans, and either filtered or be allowed to settle, 
and the clear liquor further evaporated. As for filtration, that is quite 
out of the question, but it is certain that much impurity is deposited 
when the hot solutions are allowed to cool. In woiks where 10,000 
gallons of lime salt liquor are made every week and have to be 
evaporated, this could not be effected without a considerably in- 
creased expenditure of fuel and labor. The following sketch of a 
drying furnace and of directions for drying the acetate of lime will 
be found useful. 
The drying furnace is a simple wind furnace, seven or eight feet 
long, and four and a half to five feet broad, built of brick. At six 
inches above the ground is an ash pit, eight inches broad and twelve 
inches high, which is covered with a grate of bricks. The fire- 
place is twenty inches high, and ten inches broad at the grate ; 
over it is an arch of bricks, so that the fire cannot play on and heat 
very highly the iron drying-plate lying on the side of the hearth. 
The space below the drying-plate is separated from the earth by a 
partition of bricks three or four inches high ; twelve inches above 
the outlet of the hearth there is a layer of iron bars, one and a half 
to two feet from each other, and upon these is deposited the drying- 
plate. This consists of cast-iron, one quarter of an inch thick, and 
is formed according to the size of the furnace. Round the plate 
the furnace is built up to the height of ten inches, on the side of 
the front wall, leaving room for doors, which may be calculated at 
two and a half feet. These doors are two, one above the ether, 
through which the whole interior of the furnace can be inspected. 
They are formed of plate-iron and have in their middle a sliding 
door to admit of the exit of the vapour of the acetate of lime, and 
of some ventilation. A wall built at the end of the plate, or clay 
partition, separates the whole of the drying plate from the chimney. 
In the walls of the furnace iron bars are fixed, and upon these bars 
a second drying-plate, which covers the drying space. This plate, 
as it does not come in contact with the fire, may consist of good iron 
or of clay. 
