China Green.

Scientific American 19, 11.5.1867

China green, or lo-kao, has been produced by Mr. Charvin from the Rhamnus Carthaticus, forming as beautiful a dye as the original of the same name. The process allows the article to be afforded for $8.90 per pound, and is as follows: Two pounds of the bark is placed in a kettle of boiling water; in a few minutes a pink scum is produced, when the whole is placed in an earthen jug well covered, until the next day. The liquid, not yellowish, is turned reddish brown by the addition of lime water, and is then distributed in glass jars, very little in each, and thus exposed to air and light, when it takes a green shade. This becomes gradually more general, and the whole is mixed together and carbonate of potash is added, producing a green precipitate, which is finally collected and dried.

Ei kommentteja :