permanent memorial to his name in Hofmann House, the home of the German Chemical Society (of which he was the founder), which was formally opened in 1900, appropriately enough with an account of that great triumph of German chemical enterprise, the industrial manufacture of synthetical indigo. Hofmann's work covered a wide range of organic chemistry, though with inorganic bodies he did but little. His first research, carried out in Liebig's laboratory at Giessen, was on coal-tar, and his investigation of the organic bases in coal-gas naphtha established the nature of aniline. This substance he used to refer to as his first love, and it was a love to which he remained faithful throughout his life. His perception of the analogy between it and ammonia led to his famous work on the amines and ammonium bases and the allied organic phosphorus compounds, while his researches on rosaniline, which he first prepared in 1858, formed the first of a series of investigations on colouring matters which only ended with quinoline red in 1887. But in addition to these and numberless other investigations for which he was responsible the influence he exercised through his pupils must also be taken into account. As a teacher, besides the power of accurately gauging the character and capabilities of those who studied under him, he had the faculty of infecting them with his own enthusiasm, and thus of stimulating them to put forward their best efforts. In the lecture-room he laid great stress on the importance of experimental demonstrations, paying particular attention to their selection and arrangement, though, since he himself was a somewhat clumsy manipulator, their actual exhibition was generally entrusted to his assistants. He was the possessor of a clear and graceful, if somewhat florid, style, which showed to special advantage in his numerous obituary notices or encomiums (collected and published in three volumes _Zur Erinnerung an vorangegangene Freunde_, 1888). He also excelled as a speaker, particularly at gatherings of an international character, for in addition to his native German he could speak English, French and Italian with fluency. See _Memorial Lectures delivered before the Chemical Society, 1893-1900_ (London, 1901).