ON WHITE LEAD. 
69 
alcali into the water in which metallic lead was triturated to 
form an oxide, and from that a carbonate, even if there were 
no other grounds to repudiate such a process. So far from ac- 
celerating, it must have retarded the operation. 
Bonsdorf found still farther, that if, instead of permitting 
the lead to form a hydrate by resting in the water, it were put 
into a flask and the latter closed up and shaken, suboxide alone 
formed on the surface. He explains the fact on the theory, 
that when the lead is at rest, electric currents are formed be- 
tween the metal and its oxidized points, which determine a 
higher oxidation, even as far as red lead, according to"his ob- 
servations, while, by shaking, the currents are disturbed, and 
the whole surface of the lead becomes suboxidized, which pre- 
vents further oxidation even if left at rest. Hence it follows, 
that the lead must first be uniformly suboxidized by trituration, 
and as it passes into a higher state of oxidation takes up water 
and'carbonic acid, but in the third patent a portion of the ox- 
ide and carbonate evidently formed after exposure to the at- 
mosphere. It is probable that in all such cases where carbo- 
nic acid is not artificially used, a certain quantity of that acid 
will be absorbed by the oxides upon exposure to the air sub- 
sequent to attrition. The comminuted lead, when taken 
from the trays, where lead was only moistened, has the dark 
gray color of suboxide, and first assumes its white appearance 
by exposure to the atmosphere. 
The same chemist exposed a lead plate to moist air 
until the whole surface was suboxidized, then removed it from 
a portion of the surface and covered this with water, at which 
place a vegetation was formed, which he found to consist of 
one atom of carbonate, and one atom of hydrate of lead. It 
is therefore a simple hydrocarbonate of lead. This is, in all 
probability, the substance that is formed in the first four 
patents, where carbonic acid was not artificially introduced; 
for where the quantity of this acid isas small as that contained 
in the atmosphere, and, where the tendency of the lead is also 
to form a hydrate, it is not probable that this acid should in 
