Gold Blue
:
ON THE PRIMARY, BLUE.
Gold purple, under the name of Purple of Cassius, was once very well
known: a like compound of tin and gold may be made to yield a blue.
Resembling indigo, the colour is not remarkably brilliant, and, unless
several precautions are carefully observed, is rather violet than blue.
When obtained, the colour must be quickly washed by decantation, or it
changes first to violet and then to purple. Its costliness, lack of
brightness, and tendency to redden, are against its employment on the
palette. In enamelling it would doubtless preserve its colour, and in
exceptional cases might be useful.