MANUFACTURE OF ACETATE OF LIME. 
51 
of litmus paper is no longer reddened ; a slight excess of lime is 
then added, with a view to render the separation of the oily matters 
more complete. A portion of the tarry matters are carried to the 
bottom with the impurities of the chalk or lime employed, and part 
of the oily matters, combined with the lime, float on the surface, and 
are removed by skimming. The solution of acetate of lime when 
clear, is ready for the evaporating pans,which are either wood vessels 
lined with lead and furnished with coils of wrought iron steam pipes 
in connection with a boiler, or shallow pans of sheet iron, set over 
a naked fire — the boiling solution is repeatedly skimmed to remove 
the tarry matter floating on the surface ; and the salt as fast as formed 
is fished out by means of large skimmers, and thrown into wicker 
baskets suspended over the pans, so that the liquor draining from 
the salt may not be allowed to cool. The following practical result 
was obtained by the use of three sheet-iron pans about eighteen 
inches in depth, and capable of containing 450 gallons of acetate of 
lime liquor each : — First six days of 24 hours each, 7020 gallons of 
liquor were evaporated, producing 78 cwt. of dry acetate of lime. 
Second week, 8060 gallons were evaporated, producing 92 cwt. of 
dry acetate. Third week, 7000 gallons were evaporated, producing 
78 cwt. of dry acetate. Two of the pans contained brown acetate 
of lime liquor, and the other grey acetate liquor. 
The next part of the process is the drying of the drained acetate 
of lime. This is usually effected by placing it on the top of the mass 
of brickwork in which the retorts, or cylinders, or ovens, are set ; 
but as there is seldom room to dry the whole of the salt in this way, 
many works are furnished with a drying-house in addition, and, 
where the lime is made on the spot, the waste heat from the kiln or 
furnace is made available for drying the acetate, it being made to 
traverse the flues beneath the floor of the drying house. As a 
general rule, however, the drying of the acetate of lime is a part of 
the process of this manufacture by no means well executed, requir- 
ing as it does, more attention than the workmen are usually disposed 
to give to it. 
Some very good directions have been given by Pliicker for the 
manufacture of acetate of lime, though some of them are not readi- 
ly practicable on the large scale, and would require more additional 
labor and fuel than would be compensated for by the extra price 
to be obtained for the acetate in the market. He recommends the 
