150 DYES. 



In 1 030 it was discovered in Holland that the oxide of tin 

 had the power of exalting the scarlet color of cochineal, and 

 soon after one of the celebrated MM. Gobelins, at Paris, 

 availed themselves of the discovery in their famed tapestries. 

 The nitrate or nitromuriate of tin produces the natural color 

 of cochineal-crimson, which is changed to scarlet by the 

 tartar employed in the process. Cochineal is soluble in 

 water, and is fixed on cloth by means of alumina or the 

 oxide of tin. 



Madder, the root of the Rutia tinctorum, is one of the 

 most valuable drugs used for dyeing. The plant is much 

 cultivated in Europe, and particularly in Holland. It tinges 

 with red the bones of the animals that feed on it. Madder 

 produces, by the medium of different mordants, every shade 

 of red, purple, and black. 



Smyrna Madder is the root of the Riibia peregrina, and 

 the dye obtained from it is principally used for dyeing the 

 Turkey red on cotton, with the adjuncts of oil, galls, alum, 

 and some blood (which appears to exalt the color), and sub- 

 stances which, in passing through the alimentary canal of 

 sheep, have imbibed and retained some of the gastric fluids ; 

 the manufacture of Turkey cotton being a complicated process. 



YELLOW DYES. 



The yellow dyes in most common use are the quercitron- 

 bark, weld, fustic, saffron, turmeric, and hickory. 



Quercitron-bark, the most valuable of the yellow dyes, was 

 discovered by Dr. Bancroft, to whom the English govern- 

 ment, with its accustomed liberality, granted the right of 

 disposal for a number of years. This dye is an extract 

 from the bark of the Quercus tinctoria, or common black 

 oak of the United States. Like most of the yellow dyes, 

 it is an adjective color. With a basis of alumina, the de- 

 coction presents a bright yellow dye ; with the oxide of tin, a 



