The coal tar industry holds a unique position in the industrial world. as it is entirely the outcome of scientific research. The first seed was planted in 182,5 when Faraday discovered benzene, which he obtained from the liquid products condensed on compressing the gas obtained from coal oil. A year later. 1626. Unverdorben obtained aniline by the mere distillation of indigo and called it "crystalline". Runge afterwards obtained it from coal tar oil, and having observed that it produced a violet blue coloration with chloride of lime, called it "kyanol." It was subsequently obtained from indigo by Fritsche by distilling this coloring matter with caustic alkali. Mitsch-erlich later obtained benzene from benzoic acid and from this produced nitrobenzene, this discovery paving the way for Zinin, who showed that benzidam (aniline) could be produced by the action of sulphuretted hydrogen in the presence of ammonia on an alcoholic solution of nitrobenzene.