ON WHITE LEAD. 
77 
lead, and 6,000 oz. of dry acid. But this acid would consist 
of 2852.4 carbon, 279S.4 oxygen, and 349.2 hydrogen in 
ounces. Then the 2852.4 oz. of carbon, if converted into 
carbonic acid, would take up 3,015 lbs. of lead to form a car- 
bonate, or about one-sixth of the metal contained in the bed, 
while the above amount of oxygen would only take up 2,268 
lbs. of lead to make an oxide, or one-eighth of the amount of 
metal which is present. It follows clearly that the acetic 
acid is neither employed to yield oxygen for oxidizing, nor 
carbon for ^producing a carbonate, to any appreciable extent, 
and, moreover, it should not be forgotten that a much smaller 
quantity of vinegar will suffice to produce a carbonate than is 
specified above. The chief products arising from the fer- 
mentation of dung are carbonic acid, carbonate of ammonia 
and water, the second^of which may be omitted, as it arises 
in small quantity from tan, which is employed with success in 
England. The heat of fermentation then will raise vapour of 
vinegar, carbonic acid and water; but there is another mate- 
rial of value present in this process, the atmosphere, notwith- 
standing experiments made in Europe,* which seemed to 
show that its presence deteriorated the color of the white 
lead; for in all the ordinary processes it must be present, and 
in those which follow it has been shown by direct experiment 
to be essential to the formation of oxide. The moisture which 
is present appears to act chiefly by determining the action of 
the other substances, and not to be decomposed, for we have 
no evidence of its decomposition, and the changes which en- 
sue to the lead can be satisfactorily explained without it. It 
may, however/be^maintained that it assists in forming oxide, 
but in the subsequent experiments, air being found necessary, 
proves that the chief use of the latter is to oxidize the lead. 
We have shown above that in Bonsdorf's experiments the 
lead will oxidize in a moist atmosphere, and that the presence 
of carbonic acid tends'to hasten the operation, with the pro- 
duction of a carbonate; acetic acid, then, by its more ener- 
getic action, will surely produce an acetate, and where its 
* Berzelius' Elements of Chemistry. 
