ON WHITE LEAD. 
79 
gradual escape of a portion of the vinegar. We are not, how- 
ever, left in doubt as to the latter point, for it has been found 
that a peculiar etherial substance is obtained during the pro- 
cess, called acetone, which may be obtained by passing acetic 
acid through a heated glass tube, or by the dry distillation of 
an acetate. It is composed, according to the views of the 
best chemists, of 3 vol. carbon + 6 vol. hydrogen + 1 vol. oxy- 
gen, and its origin from acetic acid may be thus expressed, 
1 atom acetic acid, - - - 4C + 6H + 30 
Subtract 1 atom carbonic acid, - C +20 
There remains 1 atom of acetone, 3 C + 6 H + l 
So that acetic acid is resolved into acetone and carbonic acid. 
By heating the neutral dry acetate of lead, it fuses and evolves 
carbonic acid and acetone to a given point, when it congeals and 
forms a basic (two-thirds,) acetate, which requires a higher 
temperature for its decomposition. One-third of the acetic 
acid in the neutral salt is thus decomposed, and there remains 
a basic salt.* Now if the above given explanation of the for- 
mation of carbonate of lead be correct, then from the middle, 
towards the close of the process, when a neutral salt will be 
forming, the constant presence of a considerable amount of 
heat will tend to form acetone and carbonic acid, the former 
of which escapes into the atmosphere, while the latter assists 
in decomposing the basic acetate which remains. The latter 
is thus re-resolved into a neutral salt to be again subjected to the 
same decomposition as before. It might be supposed that 
this theory would account for the formation of all the carbo- 
nate of lead, but it has been shown above that the quantity of 
vinegar is too small as compared with the metallic lead, and 
from the relative amount of the two, the conversion of the 
greater part of the lead into its carbonic must be explained on 
Thenard's principle. 
These views of the author were first cursorily expressed in 
* Wohler in Berzelius' Chemistry, vol. viii., p. 698. 
