This is a yellow protoxide of lead, which has been melted, and left to
crystallize by cooling. It is in the form of small reddish, or yellowish
scales, which are brilliant and vitrified. Its character is so peculiar
that it cannot easily be mistaken. It is employed for various purposes
in the arts, and is the saturnine preparation more usually selected for
the purpose of removing acidity from wines, as above related.
When treated with a muriatic salt, and submitted to a high temperature,
a _muriate of lead_ is produced, of a bright yellow colour, the
brilliancy of which may be much heightened by grinding it as usual with
oil. In this state it forms the pigment known by the name of _Turner’s
yellow_, or _patent yellow_.[376] It is very poisonous.