CHAPTER XVI 

 DYES 



Dyes. One of the most important and lucrative industrial 

 processes of the world to-day is that of staining and dyeing. 

 Whether we consider the innumerable shades of leather used 

 in shoes and harnesses and upholstery ; the multitude of colors 

 in the paper which covers our walls ; the artificial scenery which 

 adorns the stage and by its imitation of trees and flowers and 

 sky translates us to the Forest of Arden ; or whether we con- 

 sider the uncounted varieties of color in dress materials, in 

 carpets, and in hangings, we are dealing with substances 

 which owe their beauty to dyes and dyestuffs. 



The coloring of textile fabrics, such as cotton, wool, and 

 silk, far outranks in amount and importance that of leather, 

 paper, and the like ; hence the former only will be considered 

 here. But the theories and facts relative to textile dyeing are 

 applicable in a general way to all other forms as well. 



Plants as a source of dyes. Among the most beautiful 

 examples of man's handiwork are the baskets and blankets 

 of the North American Indians, woven with a skill which can- 

 not be equaled by manufacturers, and dyed in mellow colors 

 with a few simple dyes extracted from local plants. The 

 magnificent rugs and tapestries of Persia and Turkey, and 

 the silks of India and Japan, give evidence that a knowledge 

 of dyes is widespread and ancient. Until recently, the vege- 

 table world was the source of practically all coloring matter, 

 the pulverized root of the madder plant yielding the reds, the 

 leaves and stems of the indigo plant the blues, the heartwood 



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