54 
MANUFACTURE OF ACETONE. 
from the acetate of lime, but a chemical influence is exerted by- 
means of it ; because it is certain that the substances formed by dry 
distillation, which have been recently distinguished by Reichenbach, 
are partly dissipated by the heat, and'partly decomposed, the acetate 
of lime possessing very different properties before and after the pro- 
cess. After the process the salt does not imbibe water so readily as 
it did previously. After solution, nitration, and evaporation, a much 
purer product is obtained than before, and upon the filter a resinous 
matter remains, the constituents of which have not yet been 
examined. 
It will be seen from an inspection of one of the tables given under 
Parti., that the quantity of acetate of lime obtained from a given 
weight of wood varies according to the kind of wood employed ; it 
may however be estimated on the large scale as about 140 pounds 
of brown salt per ton of wood of average dryness, the average result 
obtained at one works from nearly 2000 tons of wood, and at another 
from the weekly consumption of 80 tons, being as near as possible 
that amount ; larger products have been obtained, even as high as 
150 pounds, but the quantity above stated is a fair estimate of the 
produce on the large scale. 
Manufacture of Pyro-acetic Spirit, or Acetone. — The usual mode 
of obtaining pyro-acetic spirit is by the decomposition of the acetates 
by means of heat. For this purpose the acetate is submitted to dry 
distillation in a retort, great attention being paid to the temperature, 
which should be kept as low as possible consistent with the decom- 
position of the acetate employed. The distillation should be con- 
ducted with a slowly increasing heat, as the quicker the temperature 
is raised, the larger is the quantity of pyro-acetic spirit destroyed, 
carbon remains in the retort, and the empyreumatic oil formed 
renders the spirit impure. In the case of the metallic acetates, 
water, acetic acid, and pyro-acetic spirit, pass off in a state of vapor, 
and are condensed ; carbonic acid and carburetted hydrogen gases 
are the incondensable products, whilst the metallic base, mixed with 
some carbonaceous matter, remains in the retort. The metallic base 
is usually reduced to the metallic state, and the more difficult this 
reduction is, the greater is the quantity of pyro-acetic spirit formed. 
Acetates, the bases of which retain carbonic acid at a red heat, 
produce, when heated in close vessels, the carbonate of the base and 
