Lyon Playfair (1819-1898) in 1885 when President of the British Association for the Advancement of Science. Scottish chemist and politician. He studied chemistry at Glasgow under Thomas Graham, and under Liebig at Giessen. Professor chemistry at Edinburgh university 1858-1896. Discovered the nitroprusside class of salts. Chemist to the Geological Survey, 1846. Fellow of the Royal Society 1848. Liberal MP for the universities of Glasgow and Edinburgh 1868-1885. Secretary of State for Science and Art 1855. Deputy Speaker of the House of Commons 1880-1883. (London 1877). Etching from Quasi Cursores by William Hole (Edinburgh, 1884).