(1700) Dyeing Vegetable Ivory. (1707) Platina Varnish.

The Manufacturer and Builder 11, 1876

(1700) Dyeing Vegetable Ivory.
Yes; the dyes commonly used for wool will also dye real ivory. Vegetable ivory however does not take red colors quite as well as the animal article; however there is not much trouble about it. We do not know of any book specially written on dyeing ivory; but no doubt you may obtain a great deal of information from any good book on dyeing in general. We will add for your information that Black is obtained by steeping the articles in a weak solution of nitrate of silver, and then exposing it to the light; or by boiling the ivory first in a solution of logwood and then steeping it in a solution of sulphate of iron, thus making an ink. Red is obtained by an infusion of cochineal in liquid ammonia; the articles are first soaked in a water slightly acidulated with nitric or acetic acid. Blue is obtained by a solution of indigo in sulphuric acid which has been diluted and neutralized with chalk or potash. Green is obtained by a solution of verdigris in vinegar. Yellow by a bath of chromate of potash, and afterward in a boiling solution of acetate of lead. Purple by a neutral solution of chlorid of gold, and then exposure to the light.

(1707) Platina Varnish.
This varnish has been analyzed by Dr. Filsinger, of Dresden, who has published the results for the benefit of all interested. Various qualities are sold, distinguished by numbers, from No. 15 to No. 1, No. 0, and No. 00. No. 15 was found to consists of 35 per cent of linseed-oil vanish and 65 of yellow ocher; No. 11, of 37 of linseed-oil varnish and 78 of clayish iron ocher and pulverized zinc; No. 00, of 23 of linseed-oil varnish and 77 of clayish iron ocher and more pulverized size. Other ingredients besides these were not present in any of the varnishes. That a manufacturer should recommend oil paints which consist of nothing but ocher and varnish as something new very valuable, is neither original nor uncommon, but it can not be considered a very creditable act.

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