Lord Kelvin

(William Thomson). Born June 26, 1824, in Belfast; died Dec. 17, 1907, in Largs, near Glasgow; buried in London. British physicist; one of the founders of thermodynamics and the kinetic theory of gases. Fellow of the Royal Society of London (1851); president of the society from 1890 to 1895.

Thomson studied at the universities of Glasgow and Cambridge from 1834 to 1845. For a few months in 1845 he worked in the laboratory of H.-V. Regnault in Paris. He was a professor at the University of Glasgow from 1846 to 1899. For his contributions to science, he was raised to the peerage in 1892 as Baron Kelvin of Largs.

While still a student, Thomson published a number of papers on the application of Fourier series in various areas of physics. In 1845 he developed an electrical method of obtaining images.

Influenced by the work of J. P. Joule, Thomson turned his attention to fundamental problems of the theory of heat. He proposed an absolute temperature scale in 1848 and set forth a formulation of the second law of thermodynamics in 1851. He introduced the concept of the dissipation of energy and advanced the hypothesis of the heat death of the universe. During this period, it may be noted, Thomson continued to work in other areas of physics; in 1851, for example, he discovered that the electrical resistance of ferromagnetics changes when they are magnetized. In 1853 and 1854, in collaboration with Joule, he discovered what is now called the Joule-Thomson effect: the change of temperature of a gas undergoing adiabatic expansion. Thomson developed a thermodynamic theory of thermoelectric phenomena. In 1854 he predicted that heat is transferred between a current-carrying conductor and its surroundings in the presence of a temperature gradient; this phenomenon is now known as the Thomson effect.

Thomson made important contributions to the difficult problem of laying a telegraph cable under the Atlantic. He developed a theory of electromagnetic oscillations and derived a formula giving the dependence of the period of the oscillations of a circuit on the circuit’s capacitance and self-inductance.

Thomson’s calculation of the sizes of molecules on the basis of measurements of the surface energy of a liquid film was of considerable importance in the development of atomistic concepts. In 1870 he established the dependence of the pressure of a saturated vapor on the shape of the liquid surface. Thomson studied various problems in hydrodynamics, particularly in the theory of tides and in the theory of wave propagation over a surface. He developed a theory of vortex motion and derived a theorem stating that the circulation around a closed path in an ideal fluid does not change with time.

Thomson did considerable work in other fields as well. In astrophysics, for example, he set forth a theory of the origin of the zodiacal light. In geophysics he advanced a theory of the cooling of the earth. Among his inventions are the siphon recorder, the quadrant electrometer, and the absolute electrometer. He made improvements in the mirror galvanometer, the magnetic compass, and a number of other devices.

Thomson was elected an honorary corresponding member of the St. Petersburg Academy of Sciences in 1877 and an honorary member of the academy in 1896.