Sir Harold Brewer Hartley GCVO CH FRS was a British physical chemist. He moved from academia to important positions in business and industry.
He was the son of the collector and bibliophile Harold T. Hartley, and was educated at Dulwich College, and Balliol College, Oxford. As a tutor at Balliol, he supervised the research of Edmund Bowen and Cyril Hinshelwood.
Hartley served in the First World War and was awarded the Military Cross. He was Bedford Lecturer in Physical Chemistry, at Balliol College, University of Oxford. He was knighted in 1928, made KCVO in 1944, GCVO in 1957 and Companion of Honour in 1967.
He was elected a Fellow of the Royal Society in May, 1926. His candidacy citation read: "Distinguished for his investigations in physical and mineralogical chemistry, including electrical conductivity, ionisation, and electrolytic equilibria in aqueous and non-aqueous solutions. Has greatly contributed by his own work and that of his pupils to the building up of a notable school of physico-chemical research at Oxford. During the war and afterwards has done valuable work in connection with gas services. Acted as Chemical Adviser to the Third Army in France. Appointed Assistant Director of Gas Services, GHQ. Later appointed Controller of Chemical Warfare Department, with the rank of Brigadier-General". He received the Hoover Medal in 1968.