Henry Enfield Roscoe (January 7, 1833 - December 18, 1915) was an English chemist. His scientific work includes a memorable series of researches carried out with Bunsen between 1855 and 1862, in which they laid the foundations of comparative photochemistry. In 1864 they carried out what is reputed to be the first flashlight photography, using magnesium as a light source. In 1867, he began an investigation of vanadium and its compounds, and devised a process for preparing it pure in the metallic state, at the same time showing that the substance which had previously passed for the metal was contaminated with oxygen. He also carried out researches on niobium, tungsten, uranium, perchloric acid, and the solubility of ammonia. He was knighted in 1884. He served on several royal commissions appointed to consider educational questions, and from 1896 to 1902 was vice-chancellor of the University of London. He died in 1915 at the age of 82.