Litharge Is Merely Fused Massicot Old Writers Speak Of Litharge Of
:
ON THE PRIMARY, YELLOW.
silver and litharge of gold, oxides of lead, pale and reddish yellow
respectively. Commercial litharge, especially that which is foreign,
contains sometimes a considerable proportion of oxide of copper and
iron. The principal impurity, however, is generally silica, left
undissolved on treating the litharge with nitric or acetic acid.
Litharge is commonly used in preparing drying oils, which contain a
greater or less am
unt of the oxide in the form of oleate of lead. Oils
made siccative by means of litharge are therefore liable to be damaged
by foul gas. It is a matter of congratulation that such injury is not
lasting, and that the oil, like white lead, recovers its original colour
on exposure to air and light. Some drying oil which we exposed on a tile
to an atmosphere of sulphuretted hydrogen until it was completely
blackened, regained its former yellow hue on being submitted for a day
or so to air and light. Hence, although the employment of lead as a
siccative is not desirable, its effects are not so deleterious as might
be imagined.