Alexander Oliver Rankine was born at Guildford in 1881, the son of the Rev. John Rankine, a Baptist minister. Both his father and mother were of Scottish descent. He had one brother and two sisters. He was educated at the Royal Grammar School, Guildford, after a period at a Board School. From Guildford he went with a county major scholarship to University College London, where he graduated with first class honours in physics in 1904. In 1910 he became a D.Sc. of the University. He was assistant in the Department of Physics in University College from 1904 to 1919, except for a period of war service from 1917-1918. He worked then under W. H. Bragg (later Sir William) first at Aberdour on the Firth of Forth, then at Harwich as Deputy Resident Director under Professor (then Colonel) A. S. Eve, and finally as Director of a new station at Dartmouth, or rather Kingswear. This involved some administrative responsibilities, and he showed tact and ability in handling the problems in war-time of an experimental station concerned with getting scientific gear into service. His main personal research contribution was a device, called the Photophone, for transmitting speech by means of a beam of light, but he also worked on acoustic and electromagnetic means of submarine detection. For his work in the War he received the O.B.E. Soon after the end of the War, in 1919, he was appointed Professor of Physics at Imperial College, South Kensington, in succession to Lord Rayleigh, this was the second chair in the department, Callendar holding the first. However, when Professor F. J. Cheshire retired in 1925 from the post of Director of the Technical Optics Department, Rankine was appointed to that post, which he held until 1931 when the Technical Optics Department was amalgamated with that of Physics, and he returned to his former position.
