Читать книгу The Practical Ostrich Feather Dyer - Alexander Bartlett Paul - Страница 14

Oxalic acid, a most powerful acid, occurs combined chiefly with potash juices of plants of the genus oxalis and rumex. Artificially it was obtained by the action of nitric acid upon sugar and starch, but has been prepared latterly by treating spent dyestuffs with alkalies. Oxalic acid forms colorless transparent crystals, which are inodorous, intensely sour, and do not grow moist upon exposure. Should they become damp, some nitric or sulphuric acid, used in the preparation, has not been thoroughly removed. It is soluble in its own weight of boiling water, but requires about eight times its weight of water at 65° Fah. Oxalic is one of the largely used acids in feather dyeing, being used in a number of light colors for the purpose of developing the color. In developing blues it is invaluable. Other colors it will totally destroy, violet or safranine, for example; and it is used in place of sulphuric acid for the purpose of extracting color.