50 
MANUFACTURE OF ACETATE OF LIME. 
also by the more or less careful management of the several pro- 
cesses it is made to undergo. The question then naturally arises, 
how are we to judge of the quality of wood spirit ? — will a know- 
ledge of its specific gravity, or of its boiling point, guide us in this 
respect 1 If a wood spirit be required for burning in a spirit lamp, 
or for singeing horses, there can be no doubt but that the spirit of 
the lowest specific gravity is the best ; but if the wood spirit be 
required for the manufacture of varnishes and polishes, especially 
those containing gum sandrac, then the above criterion will not 
apply. For instance, a sample of wood spirit containing 85 per 
cent, has been far preferred to that of another sample containing 
95 per cent. We have invariably found that the wood spirit ob- 
tained by liming the crude liquor from the cylinders before distilla- 
tion, does not dissolve sandrac, whilst that obtained by distilling 
off the spirituous portion of the crude liquor before liming, is 
a good solvent of sandrac, the spirit in the first case being of 
a low specific gravity, and miscible with water, whilst the lat- 
ter contained less real spirit, and was rendered milky on the addi- 
tion of water. At one works, upwards of two and three-quarter 
gallons per ton have been obtained on the average working of 
nearly 2000 tons of wood ; whilst at another, a weekly consump- 
tion of 80 tons of wood has yielded only 160 gallons of pyroxylic 
spirit ; and at a third, only 42 gallons have been obtained from 36 
tons of wood. 
Manufacture of Acetate of Lime. — The commercial acetate of 
lime is of two qualities, respectively designated grey and brown 
lime salt ; these are obtained by saturating with lime either the dis- 
tilled acid before mentioned, or the undistilled acid after the pyroxy- 
lic spirit has been removed by distillation, and evaporating the 
clear solution almost to dryness, or by evaporating the solu- 
tion of acetate of lime as run off from the stills in the case in 
which the crude acid has been neutralized with lime previous to the 
distillation of the spirituous product. This saturation either of the 
crude acid previous to distillation, or the distilled acid, or the un- 
distilled acid, is in either case performed in the same manner. The 
acid liquor is passed into wooden or iron vessels of convenient ca- 
pacity, say from 500 to 1000 gallons each, and a quantity of either 
powdered chalk or of slacked and sifted lime, previously made into 
the consistence of cream with water, is added until the blue color 
