A NEW TRIUMPH OF CHEMICAL SYNTHESIS

Abstract

THE year 1868 was a marked epoch in the progress of chemical synthesis as well as of tinctorial processes. The German chemists. Profs. Graebe and Liebermann, succeeded at that date in preparing from the hydrocarbon anthracene manufactured from coal tar the brilliant dye-stuffs hitherto won from madder, and in establishing also the chemical constitution of these various compounds and their relationship to other well-known bodies. This was the first instance in which the chemist had succeeded in artificially preparing colours occurring in the vegetable kingdom; and although the manufacture of artificial madder colouring matters has assumed at the present day colossal proportions and bids fair to entirely supersede the preparation of the natural products, it has hitherto remained the only instance of the kind in the history of chemistry, all other vegetable and animal dyes obstinately refusing to disclose the secret of their composition and be classified among the compounds of well-defined molecular structure. Within the past few weeks the madder colours have ceased to occupy this unique position. Modern chemistry has succeeded in preparing synthetically none other than common indigo, the well-known product of the Isatis tinctoria, and Nerium tinctorium of India and South America.