Australian Dictionary of Biography

John Keith Roberts (1897-1944), physicist, was born on 16 April 1897 at Kew, Melbourne, elder child of Australian-born parents Henry Charles Roberts, sharebroker, and his wife Winifred Mary, née French. His parents and his sister Winifred were capable musicians. Keith sang and played the violin; music was always an important part of his life. At Camberwell Grammar School he qualified for university entrance in 1913. His father was keen for him to go into commerce and he spent an unhappy year working for a firm in the city before enrolling at the University of Melbourne (B.Sc., 1918; M.Sc., 1920).

Graduating with first-class honours, the Dixson scholarship in natural philosophy and a government research scholarship, Roberts assisted Professor T. H. Laby in the early stages of the latter's classic redetermination of the mechanical equivalent of heat. Roberts wrote two papers (one jointly with Laby) which were published by the Royal Society of Victoria in 1920. An 1851 Exhibition science research scholarship enabled him to go to England to work at the Cavendish Laboratory, Cambridge (Ph.D., 1923; Sc.D., 1941), under Sir Ernest (Baron) Rutherford.

Roberts became briefly involved in the initial, unsuccessful search for the neutron. Chiefly, however, his research continued to focus on precision measurement, and he wrote a thesis on conservation of energy in hydrogen discharge. Appointed to Britain's National Physical Laboratory in October 1922, he worked in the heat section, making precise determinations of the thermal properties of metallic crystals. At the register office, Kensington, London, on 5 June 1924 he married Margaret Sylvia Whyte, a divorcee and daughter of the wallpaper manufacturer Harold Sanderson. Later that year Roberts developed a tubercular hip. Seriously ill, he was sent to a sanatorium in Switzerland where he spent much of the next four years lying on his back. In this position he wrote his well-known treatise, Heat and Thermodynamics (London, 1928).

In 1928 Roberts returned to England and rejoined the Cavendish Laboratory. An excellent lecturer, and a careful and conscientious teacher, he transferred in 1933 to Cambridge's colloid science laboratory as assistant-director of research. An investigation of energy exchanges between hot surfaces and the gases in contact with them led him into a long and highly successful study of the adsorption of gases by metal surfaces. For this work he was elected a fellow (1942) of the Royal Society.

Following the outbreak of World War II, Roberts became a senior scientific officer with the Royal Navy, working first on the degaussing of ships and then on minesweeping. Late in 1942, at the height of the battle of the Atlantic, he was appointed chief scientist in the Anti-Submarine Experimental Establishment, Fairlie, Scotland, where he oversaw one of the great scientific achievements of the war—the development of improved equipment for detecting submarines. In February 1944 he was elected a fellow of Christ's College, Cambridge. He planned to take up the position when his wartime work finished, but he developed Addison's disease. Survived by his wife and their two daughters, he died of pneumonia and pericarditis on 26 April that year at St Marylebone, London, and was cremated.

Selfless, affectionate and humorous, Roberts was held in high regard by friends and colleagues. In his wartime posts he proved an excellent leader of large and complex projects. 'Had he survived', his obituarist in The Times asserted, 'there can be little doubt that the future of the Cavendish Laboratory would have been largely dependent on him'.