264 
MANUFACTURE OF ACETIC ACID. 
Soda by Sulphuric Acid. — Any given quantity of crystallized ace- 
tate of soda is placed in a copper still, and a hollow place having 
been made in the mass of the crystals, a quantity of strong sulphu- 
ric acid, equivalent to 34 or 35 per cent, of the weight of the ace- 
tate of soda employed, is then poured in at once, the crystals form- 
ing the sides of the heap in the still are then pushed down into the 
acid, and the whole stirred with a long broad wooden spatula ; the 
head is then put on and luted, and the connexion made with the 
refriger ator. Nearly four cwt. of acetic acid, of specific gravity 
1.050, may thus be obtained from 3 cwt. of acetate of soda, which 
only requires to be passed through a calico filter (of the form des- 
cribed in Mohr and Redwood's Practical Pharmacy, page 203, fig. 
211) [fig. 193, page 191, Amer. edit.] on which some animal char- 
coal had been placed, to fit it for the market. A small quantity 
of acetic ether is often added to flavor it. 
The still employed should be of stout copper (the solder used in 
its construction should be silver solder,) having its lower half 
set in an iron jacket, which either receives the high-pressure steam 
to be used as the beating medium, or contains oil, tallow, or fusible 
metal, according as either of these substances may be preferred for 
use. In the former case a cock is placed at the lower part of the 
casing to let off the condensed steam from time to time; and in 
the latter case the iron jacket is placed over the fire, the contents 
of the still receiving sufficient heat from the heated tallow, oil, or 
metal with which the copper is still in contact. A safety tube 
should be attached to permit the rise and escape of the heated oil, 
&c, should the temperature be raised too high. 
The head of the still is of earthenware, and an earthenware, sil- 
ver, or block tin worm may be employed to condense the acid va- 
por, according to the supply of water which can be obtained fur 
condensation ; or a series of Woulfe's stone-ware receivers, of 
about twenty gallons each, one-third full of water, may be con- 
nected with the earthenware head of the still. In this latter case, 
at the close of an operation, the acid in the first receiver will be found 
to be stronger than the second, the second than the third, &c, and 
if the union of the contents of the whole series will not furnish an 
acid of the strength required, the stronger portions may be drawn 
off from the first and second receivers, and the weaker portions in 
the third and fourth receivers may be placed in the first and second 
