RANKINE, ALEXANDER OLIVER

(b. Guildford, England, 1881; d. Hampton, Middlesex, England, 20 January 1956)

physics, geophysics.

Rankine’s father, the Reverend John Rankine, was a Baptist minister; and Rankine himself remained a member of the Baptist church. He received his professional education at University College, London, where he studied under Trouton, obtaining the D.Sc. in 1910. In 1907 he married Ruby Irene Short, the daughter of Samuel Short of Reading.

Rankine was an assistant in the physics department of University College from 1904 to 1919 and professor of physics at the Imperial College of Science and Technology, South Kensington, from 1919 to 1937, when he resigned his chair to become chief physicist with the Anglo-Iranian Oil Company. He retired from this post in 1947 but continued to act as geophysical adviser to the company until 1954. He held military research posts in both world wars and received the Order of the British Empire in 1919 for his work during World War I . He was elected a fellow of the Royal Society (1934), was an active member of several professional societies, and held various honorary positions throughout his life.

Although Rankine’s career involved him in much work of an administrative or advisory character, he also produced valuable research. His major contribution was the invention and use of an apparatus for measuring the viscosity of a gas. This apparatus, known as the Rankine viscosimeter, consisted of a vertical glass tube in which a pellet of mercury could slide downward, thereby forcing the air below it through a capillary tube connecting the lower end of the glass tube with the upper end. By enclosing the viscosimeter in a heat bath and measuring the viscosity of various gases as a function of temperature, Rankine was able to determine the so-called Sutherland constant. This constant entered into a theoretical formula—relating viscosity with temperature—that Sutherland had derived from kinetic theory and mean-free-path considerations; and the determination of its numerical value allowed Rankine to estimate the diameter of gas molecules and to arrive at some notions of their shape and atomic arrangement. This work was published in a series of articles during the period 1910–1926.

Rankine later became interested in geophysics and improved the Eötvös gravimeter; this work led him to construct a magnetometer of great sensitivity. This later instrument was used for measuring distortions, and thus susceptibilities, in weak magnetic fields.

BIBLIOGRAPHY

A complete list of Rankine’s scientific papers is given in G. P. Thomson’s biography, “Alexander Oliver Rankine,” in Biographical Memoirs of Fellows of the Royal Society, 2 (1956), 249–255.

Ole Knudsen