This dyestuff, known as red chrome and bichromate and often times
simply as chrome, consists in one equivalent of potash, with two
equivalents of chromic acid. It contains no water, and consequently
cannot lose any weight by exposure to heat or dry air. It will not
attract moisture from a damp atmosphere. It dissolves readily in ten
times its weight of cold water, and is insoluble in alcohol. It forms
bright red crystals, and the solution is of a deep orange yellow.
Bichromate of potash is a most powerful oxidizing agent, and produces
very complex and interesting changes in tinctorial bodies. It is an
intense poison. Its most extensive application is now in the production
of blacks, along with logwood; indeed, without its aid it would be next
to an impossibility to produce a glossy and permanent black on ostrich
feathers. In giving depth of shade to all dark colors it is used in
preference to any thing else, and I have never found any to contain any
adulteration that was perceptible, or that was a hindrance to its good
qualities. It is used in ostrich feather dyeing always in a diluted
form, in a very high temperature of water.