Hall, Edwin Herbert

Hall, Edwin Herbert

(b. Great Falls [now North Gorham], Maine, 7 November 1855; d. Cambridge, Massachusetts, 20 November 1938)

physics.

One of five children of Joshua Emery Hall and Lucy Ann Hilborn, only he and a younger brother survived to maturity. He prepared for college at Gorham Seminary for two years and graduated from Bowdoin in 1875. On the advice of John Trowbridge at Harvard, Hall entered the Johns Hopkins graduate school to study physics with Henry Rowland. He discovered the “Hall effect” in 1879 as a consequence of his dissertation research and received his Ph.D. in 1880. Hall remained at Johns Hopkins for another year and spent the summer of 1881 in Europe, visiting Hermann von Helmholtz’ laboratory long enough to finish some measurements on the Hall effect. In the fall he went to Harvard as an instructor; he was appointed assistant professor in 1888, professor in 1895, and Rumford professor in 1914, becoming emeritus in 1921. He was elected to the National Academy of Sciences in 1911. Hall married Caroline Eliza Bottum in 1882; they had two children.

Hall is best known for the effect bearing his name; it formed the basis of his Ph.D. dissertation and was the subject of many of his later researches. He was stimulated by Rowland to question a statement in Maxwell’s Electricity and Magnetism that the force acting on a conductor in a magnetic field acts on the conductor directly and not on the electric current. Hall’s experimental persistence was rewarded when he found that a current through a gold conductor in a magnetic field produced an electric potential perpendicular to both the current and the field. The notion that this was due to simple interaction between the current and the field had to be abandoned, however, when other metals were found for which the effect was in a direction opposite to that predicted.

Hall’s discovery was termed by Kelvin as comparable with the greatest ever made by Michael Faraday. It sparked interest in studies in this area, and three other transverse effects were soon discovered; they bear the names of Andreas von Ettingshausen, Walther Nernst, and Augusto Righi and Sylvestre Leduc.

Hall paid a great deal of attention to the possible methods of electron conduction in metals and was particularly interested in thermoelectric phenomena, especially in the years following 1914. He considered reactions between free electrons, bound electrons, and positive ions in the metallic structure; by setting up some rather arbitrary parameters and determining their values empirically, he managed to obtain reasonably consistent numbers for coefficients of the Thomson and Peltier effects. He was, however, unable to place his notions in a broader theoretical context.

Starting in 1911, Hall devoted considerable effort to very delicate experiments designed to determine precise values—measured on the same samples—for the four transverse effects. He was still at work on this problem shortly before his death.

Hall helped to stimulate the introduction of laboratory work into secondary schools and prepared a set of forty experiments that could be performed with simple apparatus. Published as Harvard Descriptive List of Elementary Physical Experiments in 1886 (later called National Physics Course), the list was designed to allow secondary schools to meet a new Harvard entrance requirement for laboratory work in physics. The effect on schools was considerable, as can be measured in part by instrument makers’ catalogs which soon appeared, describing apparatus designed for Hall’s experiments.

BIBLIOGRAPHY

I. Original, Works. A bibliography of Hall’s scientific works is given in the Bridgman article mentioned below. The Hall effect was announced in “On a New Action of the Magnet on Electric Currents,” in American Journal of Mathematics, 2 (1879), 287–292. His work on conduction theory is best represented by “On Electric Conduction and Thermoelectric Action in Metals,” in Proceedings of the American Academy of Arts and Sciences, 50 (1914), 67–103; and by “Thermo-electric Action With Dual Conduction of Electricity,” in Proceedings of the National Academy of Sciences of the United States of America, 4 (1918), 98–103; it is summarized in A Dual Theory of Conduction in Metals (Cambridge, Mass., 1938).

II. Secondary Literature. A biographical sketch of Hall, written by his colleague at Harvard, P. W. Bridgman, appears in Biographical Memoirs. National Academy of Sciences, 21 (1939–1940), 73–94; it includes a portrait and an extensive bibliography. A short notice also appears in the Dictionary of American Biography.

Bernard Finn