Thallium Orange

: ON THE SECONDARY, ORANGE.

is produced when bichromate of potash is added to a neutral salt of the

protoxide of thallium, as an orange-yellow precipitate. The scarcity of

the metal precludes their present introduction as pigments, but if the

chromates of thallium were found to resist the action of light and air,

and not to become green by deoxidation of the chromic acid, they might

possibly prove fitted for the palette. It is a question whether their



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