Page:Cyclopedia of Painting-Armstrong, George D (1908).djvu/363

Rh red. They are produced by one or two species of calamus, or cane-palm, and are used for coloring varnishes, and for dyeing horn so as to make it resemble tortoise-shell. The following are the various kinds of dragon's-blood: In sticks, called stick dragon's-blood. Dragon's-blood in drops or beads, said to be the best. Dragon's-blood in tears. Dragon's-blood in lumps.

Madder is one of the most important coloring substances known, and there are several species of it. The plant is extensively cultivated in Southern Europe and in Holland. Very large quantities of the root come from Smyrna, Trieste, Leghorn, and other Mediterranean ports, much of that which is received from Holland is in powder, and comes in large casks. The Turks formerly understood the manufacture and uses of madder better than other nations, and the color thus obtained the name of Turkey red. In commerce there are the following varieties of common madder: Smyrna, French, Syrian, and Italian roots, and French, Dutch-crop, Ombros, and Mull ground madders.

Logwood. The tree producing this dye-wood is a native of Yucatan in South America, the principal town of which, Campeachy, situated on the river San Francisco in the bay of Campeachy, was formerly the mart for logwood, but it is now extensively cultivated in Jamaica, and the chief trade is removed to Belize, a British settlement in the Bay of Honduras, whence immense quantities are annually exported.

The coloring matter of the logwood tree depends upon a peculiar principle called hæmatin or hæmatoxylin, a red crystalline substance which is so abundant in some samples as to exist in distinct blood-red crystals. The stems are cut into large logs, and the bark and alburnum or white wood is chopped off, the dark red inner wood being the only valuable portion. The color of a decoction of logwood is of a brownish blood-red. Acids change it to the bright color of red ink, which is often made of an infusion of logwood chips to which acetic acid is added. The alkalies strike a purple