Dyeing
the art of imparting colors to textile and other material, such as cotton, silk, wool, and leather. Dyeing has been practiced from time immemorial. Dyeing with colors obtained from natural products had reached a high state of perfection when Perkin, in 1856, introduced the first of the coal-tar colors.
Since that date the progress of artificial color-making has been so rapid, and the application of the new dyes made so simple, that, excepting indigo, logwood and cutch, the old colors and processes are now practically driven out of use.
If the fiber is of animal origin, such as silk or wool, a simple immersion in a bath containing the color will usually dye the fabric; but color so applied to a DYEING vegetable substance-as cotton, linen, or jute, is easily washed off, except in the case of the "direct" colors. Vegetable substances are consequently usually case of the "direct" colors. Vegetable consequently usually substances are Mordants are substances which form insoluble precipitates with the dyes in the soluble precipitates with the dyes in the body of the fiber. The mordants most largely used are tannic acid, the salts of antimony, aluminum, and chromium. Dyeing of Cotton.-The following is a brief outline of the processes in use for a few important colors:
Aniline Black is produced by mordanting the goods with salt of iron and then dyeing in a decoction of logwood or by dyeing in a bath containing logwood, bichromate of potash, and mineral acid. salts with a suitable oxidizing mixture yield a very fast and valuable black.
Bichromates and chlorates are among the substances used as oxidizing agents.
Brown is obtained by working in a catechu or cutch bath and then in a bi- Brown is obtained by working in a Bismarck-brown on a chromate bath. tannin mordant, and direct browns, are also used.
Purples and lilacs are obtained from also used. Purples and lilacs are obtained from colors, as methyl or Hofmann's violet, on a tannin mordant, and direct dyes.
Red. The fastest red dye is alizarin or Turkey red. The process is rather complicated, involving working ng in a specially Turkey red. The process is rather com- plicated, involving working in a specially ing, dyeing with alizarin, and dunging.
Reds are produced on goods impregnated B naphthol with an alkaline solution of B by passing through a bath of diazotized para, with aniline or naphthylamine.
Blue. The best blue in respect to fastness is indigo. The coloring constituent of indigo is indigotine.
Blue. The best blue in respect to fastters obtained from natural products mentioned in connection with cotton are applicable to wool, and in addition cochineal is considerably used. Cochineal with a tin mordant gives a very brilliant scarlet.
The basic colors dye wool without the aid is considerably used. Cochineal with a tin mordant gives a very brilliant scarlet. cable to wool. Aniline black is not applicable.
Dyeing of Silk. - Black is the most important color dyed on silk. In dyeing cable to wool. Aniline black is not "stuff," the fabric.
Up to the time of the outbreak of the World War, the manufacture of dyes was practically in the hands of Germany or of German controlled organizations. The World War, the manufacture of dyes was Up to the time of the outbreak of the goods, therefore, created a very serious situation in the United States and American chemists at once set themselves of German controlled organizations. The dyes which should take the place of first the results were unsatisfactory, those formerly obtained in Germany. At was able to manufacture practically all essential dyes. In that year not less than 1,733 chemists were engaged in research reached such a successful basis that it was able to manufacture practically all essential dyes. In that year not less than 1,733 chemists were engaged in research and the industry required the services of of nearly 200 firms was over 50,000,000 over 20,000 employees. The total output organized. At an exhibition held in New York City in the same year, samples of pounds, with a value of nearly $70,000,- Dyestuff Manufacturing Association was organized. At an exhibition held in New York City in the same year, samples of were shown. These samples were subdyeing from about 50 American dyestuffs jected to most severe tests, and by com- The production of coal tar dyes in the the superiority of the American product.
United States in 1918 was about 46,000,- The imports in 1915 The production of coal tar dyes in the 000 pounds.
There were exported in 1918 American amounted to practically the same figure. dyes to the value of nearly $12,000,000; in 1920 it amounted to $25,792,565.
American soldier, born in Fayetteville, N. C., in 1852. He graduated from the United States Military Academy in 1873 and in the same year was commissioned 2d lieutant of the 4th Artillery. He rose through the various grades, becoming colonel of the artillery corps in 1907. In 1913 he retired from active service. He participated in campaigns against the Indians and in the Philippines. He also served on the Mexican border in 1913.
He was the author of "Handbook for Light Artillery" (1896).