Today is the birthday of Carl Graebe, a German organic chemist born in 1841 whose work helped create the synthetic dye industry. Graebe and co-worker C. Liebermann discovered that a red dye called alizarin--then made from madder, a Eurasian herb--was a derivative of anthracene, a crystalline cyclic hydrocarbon. The duo built on the discovery to invent a commercial method of synthesizing alizarin, which became one of the early products of the German dyestuffs industry. Graebe also introduced the chemical terms "ortho," "meta," and "para," well known to organic chemistry students, which indicate the position of groups attached to a benzene ring.
[Source: Trevor I. Williams, Ed., A Biographical Dictionary of Scientists (John Wiley & Sons, ed. 3, New York, 1982).]