New Coloring Matter.

Scientific American 42, 6.7.1850

M. Garot obtains, by acting upon the root of the rhubarb by nitric acid, a substance which he calls "erythrose." It combines with the alkalies, forming coloring compounds susceptible of application in the arts. The compounds with potash and with ammonia possess, according to M. Garot, a coloring power many times greater than that of cochineal.

[The above we extract from an exhange, and have some doubts about its correctness as a whole. That its nature is different from cochineal, there can be no doubt, as the latter is an animal substance, and does not give out its coloring matter with alkalies. It may, however, be a good substitute for madder, as it gives out its coloring matter in the same way.]

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