Indigo is one of the oldest and fastest of the dyestuffs. To see that it is both ancient and lasting look at the unfaded blue cloths that enwrap an Egyptian mummy. When Caesar conquered our British ancestors he found them tattooed with woad, the native indigo. But the chief source of indigo was, as its name implies, India. In 1897 nearly a million acres in India were growing the indigo plant and the annual value of the crop was $20,000,000. Then the fall began and by 1914 India was producing only $300,000 worth! What had happened to destroy this profitable industry? Some blight or insect? No, it was simply that the Badische Anilin-und-Soda Fabrik had worked out a practical process for making artificial indigo.
That indigo on breaking up gave off aniline was discovered as early as 1840. In fact that was how aniline got its name, for when Fritzsche distilled indigo with caustic soda he called the colorless distillate "aniline," from the Arabic name for indigo, "anil" or "al-nil," that is, "the blue-stuff." But how to reverse the process and get indigo from aniline puzzled chemists for more than forty years until finally it was solved by Adolf von Baeyer of Munich, who died in 1917 at the age of eighty-four. He worked on the problem of the constitution of indigo for fifteen years and discovered several ways of making it. It is possible to start from benzene, toluene or naphthalene. The first process was the easiest, but if you will refer to the products of the distillation of tar you will find that the amount of toluene produced is less than the naphthalene, which is hard to dispose of. That is, if a dye factory had worked out a process for making indigo from toluene it would not be practicable because there was not enough toluene produced to supply the demand for indigo. So the more complicated napthalene process was chosen in preference to the others in order to utilize this by-product.
The Badische Anilin-und-Soda Fabrik spent $5,000,000 and seventeen years in chemical research before they could make indigo, but they gained a monopoly (or, to be exact, ninety-six per cent.) of the world's production. A hundred years ago indigo cost as much as $4 a pound. In 1914 we were paying fifteen cents a pound for it. Even the pauper labor of India could not compete with the German chemists at that price. At the beginning of the present century Germany was paying more than $3,000,000 a year for indigo. Fourteen years later Germany was selling indigo to the amount of $12,600,000. Besides its cheapness, artificial indigo is preferable because it is of uniform quality and greater purity. Vegetable indigo contains from forty to eighty per cent. of impurities, among them various other tinctorial substances. Artificial indigo is made pure and of any desired strength, so the dyers can depend on it.
The value of the aniline colors lies in their infinite variety. Some are fast, some will fade, some will stand wear and weather as long as the fabric, some will wash out on the spot. Dyes can be made that will attach themselves to wool, to silk or to cotton, and give it any shade of any color. The period of discovery by accident has long gone by. The chemist nowadays decides first just what kind of a dye he wants, and then goes to work systematically to make it. He begins by drawing a diagram of the molecule, double-linking nitrogen or carbon and oxygen atoms to give the required intensity, putting in acid or basic radicals to fasten it to the fiber, shifting the color back and forth along the spectrum at will by introducing methyl groups, until he gets it just to his liking.
Art can go ahead of nature in the dyestuff business. Before man found that he could make all the dyes he wanted from the tar he had been burning up at home he searched the wide world over to find colors by which he could make himself—or his wife—garments as beautiful as those that arrayed the flower, the bird and the butterfly. He sent divers down into the Mediterranean to rob the murex of his purple. He sent ships to the new world to get Brazil wood and to the oldest world for indigo. He robbed the lady cochineal of her scarlet coat. Why these peculiar substances were formed only by these particular plants, mussels and insects it is hard to understand. I don't know that Mrs. Cacti Coccus derived any benefit from her scarlet uniform when khaki would be safer, and I can't imagine that to a shellfish it was of advantage to turn red as it rots or to an indigo plant that its leaves in decomposing should turn blue. But anyhow, it was man that took advantage of them until he learned how to make his own dyestuffs.
Our independent ancestors got along so far as possible with what grew in the neighborhood. Sweetapple bark gave a fine saffron yellow. Ribbons were given the hue of the rose by poke berry juice. The Confederates in their butternut-colored uniform were almost as invisible as if in khaki or feldgrau. Madder was cultivated in the kitchen garden. Only logwood from Jamaica and indigo from India had to be imported. That we are not so independent today is our own fault, for we waste enough coal tar to supply ourselves and other countries with all the new dyes needed. It is essentially a question of economy and organization. We have forgotten how to economize, but we have learned how to organize.
The British Government gave the discoverer of mauve a title, but it did not give him any support in his endeavors to develop the industry, although England led the world in textiles and needed more dyes than any other country. So in 1874 Sir William Perkin relinquished the attempt to manufacture the dyes he had discovered because, as he said, Oxford and Cambridge refused to educate chemists or to carry on research. Their students, trained in the classics for the profession of being a gentleman, showed a decided repugnance to the laboratory on account of its bad smells. So when Hofmann went home he virtually took the infant industry along with him to Germany, where Ph.D.'s were cheap and plentiful and not afraid of bad smells. There the business throve amazingly, and by 1914 the Germans were manufacturing more than three-fourths of all the coal-tar products of the world and supplying material for most of the rest. The British cursed the universities for thus imperiling the nation through their narrowness and neglect; but this accusation, though natural, was not altogether fair, for at least half the blame should go to the British dyer, who did not care where his colors came from, so long as they were cheap. When finally the universities did turn over a new leaf and began to educate chemists, the manufacturers would not employ them. Before the war six English factories producing dyestuffs employed only 35 chemists altogether, while one German color works, the Höchster Farbwerke, employed 307 expert chemists and 74 technologists.
This firm united with the six other leading dye companies of Germany on January 1, 1916, to form a trust to last for fifty years. During this time they will maintain uniform prices and uniform wage scales and hours of labor, and exchange patents and secrets. They will divide the foreign business pro rata and share the profits. The German chemical works made big profits during the war, mostly from munitions and medicines, and will be, through this new combination, in a stronger position than ever to push the export trade.
As a consequence of letting the dye business get away from her, England found herself in a fix when war broke out. She did not have dyes for her uniforms and flags, and she did not have drugs for her wounded. She could not take advantage of the blockade to capture the German trade in Asia and South America, because she could not color her textiles. A blue cotton dyestuff that sold before the war at sixty cents a pound, brought $34 a pound. A bright pink rhodamine formerly quoted at a dollar a pound jumped to $48. When one keg of dye ordinarily worth $15 was put up at forced auction sale in 1915 it was knocked down at $1500. The Highlanders could not get the colors for their kilts until some German dyes were smuggled into England. The textile industries of Great Britain, that brought in a billion dollars a year and employed one and a half million workers, were crippled for lack of dyes. The demand for high explosives from the front could not be met because these also are largely coal-tar products. Picric acid is both a dye and an explosive. It is made from carbolic acid and the famous trinitrotoluene is made from toluene, both of which you will find in the list of the ten fundamental "crudes."
Both Great Britain and the United States realized the danger of allowing Germany to recover her former monopoly, and both have shown a readiness to cast overboard their traditional policies to meet this emergency. The British Government has discovered that a country without a tariff is a land without walls. The American Government has discovered that an industry is not benefited by being cut up into small pieces. Both governments are now doing all they can to build up big concerns and to provide them with protection. The British Government assisted in the formation of a national company for the manufacture of synthetic dyes by taking one-sixth of the stock and providing $500,000 for a research laboratory. But this effort is now reported to be "a great failure" because the Government put it in charge of the politicians instead of the chemists.