Alexander Oliver Rankine (8 December 1881 – 20 January 1956) was a British physicist who worked on the viscosity of gases, molecular dynamics, optics, acoustics and geophysics.
Career
Rankine carried out government research during both World Wars, working on anti-submarine technology and on fog dispersal systems. He studied and worked at University College London, and was a professor of physics at Imperial College London.
Rankine is most associated with the Trouton–Rankine experiment of 1908, but he also worked on early devices for the optical transmission of sound, and improved gravimeter and magnetometer designs. The latter part of his career was spent working for the Anglo-Iranian Oil Company. He also served in a range of positions with many learned societies, including periods as president of the Physical Society and secretary to the Royal Institution.
Early years
Alexander Oliver Rankine was born on 8 December 1881 in Guildford, Surrey, England. The son of the Reverend John Rankine, a Baptist minister of Scottish descent, Alexander was brought up in and was a member of the Baptist Church. Like his father, his mother was also of Scottish ancestry.
Rankine was educated at the Royal Grammar School, Guildford, and then studied at University College London (UCL), graduating in 1904 with first-class honours in physics. Following graduation, he worked as an assistant in the UCL physics department from 1904, a position he remained in until 1919 apart from a period spent doing wartime research. In 1907, he married Ruby Irene Short, with whom he had two sons and two daughters.
University College and World War I
During this period at UCL, Rankine worked under the Irish physicist Frederick Thomas Trouton. In 1908, he and Trouton carried out what become known as the Trouton–Rankine experiment. This experiment was among a number being carried out at the time, and was intended as a test of aether theory and Einstein's special relativity, with Trouton and Rankine's null result providing support for the latter theory.
Two years later, in 1910, Rankine obtained his D.Sc in Physics (awarded by the University of London). A further two years after that, in 1912, he was elected a fellow of University College. His research in this period was on the viscosity of gases, and he invented a viscosimeter (the Rankine viscosimeter), enabling him to carry out experimental determinations of the Sutherland constant (described by William Sutherland). The aim of this work was to produce estimates of the size and shape of gas molecules, and Rankine's results in this area were published between 1910 and 1926. While at UCL, Rankine also served twice as President of 'The Chemical and Physical Society' (ChemPhysSoc), the students' society of the chemistry and physics departments, doing so in the years 1910–11 and 1915–16.
During World War I, many scientists were seconded to carry out wartime research for the government. Rankine's wartime research took place in 1917 and 1918, and he worked under recently appointed UCL professor William Henry Bragg and British-born Canadian physicist Arthur Stewart Eve. Rankine worked first at Aberdour on the Firth of Forth in Scotland, then at the Harwich research station, both as part of work by the Admiralty Research Laboratory. His final posting was as Director of the research station at Kingswear. Rankine's work during this period included developing submarine detection technology.
Rankine's research during and immediately after the war also looked at ways to achieve the optical transmission of sound, a problem being worked on by other scientists and engineers in several countries. The device was similar to the photophone constructed by US inventor Alexander Graham Bell in the 1880s, and the system being developed by the Polish engineer Joseph Tykociński-Tykociner from 1918. Rankine's work in this area was mentioned in Popular Science in 1922, and has been described as an "effective technique for the transmission of speech by sunlight".
For his government research work during World War I, Rankine was made an OBE in 1919.
Imperial College and geophysics
By the time the war had ended, Rankine had added to the distinguished reputation he had gained from work in fields such as molecular dynamics, acoustics and electromagnetics. In 1919, he was appointed Professor of Physics at Imperial College, succeeding to the position held by Lord Rayleigh. It was around this time that Rankine wrote for the Encyclopædia Britannica under the initials AOR (1922 edition), contributing the article on 'Sound'