Stokes, George Gabriel

Born Aug. 13, 1819, in Skreen, County Sligo, Ireland; died Feb. 1, 1903, in Cambridge. British physicist. Fellow of the Royal Society of London (1851). The society’s secretary from 1854 to 1885 and its president from 1885 to 1890.

After graduating from Cambridge University in 1841, Stokes joined the university’s teaching staff. In 1849 he was appointed Lucasian professor of mathematics, a position that at one time had been held by I. Newton. Stokes served as a member of Parliament for Cambridge University from 1887 to 1892. In recognition of his scientific work, he was created a baronet in 1889.

Many of Stokes’ papers deal with wave processes in various media. Between 1842 and 1851 he studied the steady motion of incompressible fluids, the friction of fluids in motion, and the motion of a sphere in a viscous fluid. His work in this period is of fundamental importance for hydrodynamics (seeNAVIER-STORES EQUATIONS and STOKES’ LAW OF RESISTANCE OF A SPHERE). In 1852, Stokes described the phenomenon of fluorescence; he showed how the fluorescence spectrum depends on the spectrum of the exciting light (see), and he suggested a way of using fluorescence to investigate the ultraviolet region of the electromagnetic spectrum. Stokes’ other works on optics deal with problems of, for example, spectrum analysis, diffraction, the polarization of light waves, double refraction, the reflection of light by various surfaces, and the theory of optical instruments. In the field of optical instruments, he showed a way of improving achromatic refractor telescopes. Stokes also did important work in such areas as acoustics, heat conduction in crystals, and gravitation. His contributions to mathematics include papers on vector analysis (see), the theory of series, and the theory of definite integrals.

The unit of kinematic viscosity is named after Stokes. He was a member of many foreign academies, including the Military Medical Academy in St. Petersburg.