RICHARDSON, OWEN WILLANS

(b. Dewsbury, Yorkshire, England, 26 April 1879; d. Alton, Hampshire, England, 15 February 1959) physics, electronics, thermionics.

Richardson was one of the outstanding pure scientists behind the application of physics to the development of radio, telephony, television, and X-ray technology. An experimentalist of first rank and a foremost exponent of electrons and quantum theory throughout the first half of this century in the English-speaking world, Richardson was awarded the Nobel prize in 1928 “for his work on the thermionic phenomenon and especially for the discovery of the law named after him.” In 1939 he was knighted for his services. Between 1901 and 1953 he published over 133 papers and three books. The quality of his long and productive career as experimentalist, teacher, and administrator makes him one of the prominent physical scientists of this century.

The only son of Joshua Henry and Charlotte Maria Richardson, Owen grew up near Leeds and later in the small mining town of Askern, near Doncaster. His father was a salesman of industrial tools. By the age of twelve the boy’s precocity was so evident from his performance on parish-school examinations and his avid interest in plant life that he was admitted on a full scholarship to Batley Grammar School. From 1891 to 1897 he was a model pupil at Batley, winning many contests and exhibitions, including a scholarship to Cambridge, where he entered Trinity College in 1897. Studying at the Cavendish Laboratory under J. J. Thomson, with the group of scholars that included Ernest Rutherford, C. T. R. Wilson, Paul Langevin, and Harold A. Wilson, Richardson achieved highest distinction in classes in the natural and physical sciences. He placed first in the tripos for physics, chemistry, and botany and received his bachelor’s degree in 1900.

Invited to remain at the Cavendish Laboratory after graduation, Richardson quickly became interested in the implications of Thomson’s work on “cathode rays” and subatomic electrical “corpuscles.” Neither the physical atom nor the concept of the electron was as yet widely accepted within the physics profession; but since 1897 Thomson among others had steadily built an edifice of evidence for the particulate nature of electricity, demonstrated through the use of high vacuum techniques applied to glass tubes impregnated by electrodes. While Rutherford and others were studying the ionic forms and processes related to Röntgen rays, radioactive elements, and radiation more generally, Richardson turned to the problem of describing how the metals of heated filaments emitted their streams of charged radiant energy. In 1901 he read his first two scientific papers before the Cambridge Philosophical Society, officially announcing in the second of them (25 November 1901) an empirical law regarding the emission behavior of electrical “corpuscles” per unit time from heated platinum surfaces in a vacuum. Its immediate consequence was to win young Richardson a promising reputation and election as a fellow of Trinity College in 1902, followed by the Clerk Maxwell scholarship and a D.Sc. from University College, London, in 1904. Also during these years Richardson collaborated with H. A. Wilson and H. O. Jones on other studies in physical and organic chemistry.

In 1906, the year that Thomson became a Nobel laureate for his work on the transmission of electricity through rarefied gases, Richardson accepted an appointment as professor of physics at Princeton University. Before leaving for New Jersey, he married Lillian Maud Wilson, the sister of his friend Harold. During their seven-year stay in the United States, their two sons and one daughter were born.

Having grown ever more concerned with both Boltzmann’s statistical thermodynamics and Planck’s quantum theory for electrodynamics, Richardson while at Princeton worked sometimes alone and sometimes in collaboration with F. C. Brown, Soddy, H. L. Cooke, and R. C. Ditto to perfect apparatus, to experiment, and to publish papers on photoelectricity, spectroscopy, X rays, and thermodynamics. In 1909 he coined the term “thermionics” as a title for an article (Philosophical Magazine, 17, 6th ser., 813–833). He also then began the manuscript of his first book, The Electron Theory of Matter (1914), developed from lectures given to graduate students at Princeton, among whom were Robert H. Goddard and the brothers Arthur H. and Karl T. Compton. This book became a classic text for a generation of students interested in radio and electronics. In 1911 Richardson was elected a member of the American Philosophical Society and was thinking of becoming an American citizen. Then in 1913 the offer of the Wheatstone professorship of physics at King’s College, plus election as a fellow of the Royal Society, lured him back to the University of London.

Returning to England, Richardson left in America a legacy of rigorous teaching and research in what was beginning to be called electronic physics. Two of his sisters had married Princeton colleagues; and his brother-in-law, H. A. Wilson, had migrated from Canada to Texas. Thus family ties remained strong with the United States. Toward the end of his American sojourn, Richardson had published experimental proof that the electric current in tungsten is carried by electrons, and he had completed many other experiments on thermionic emission from various materials, on the photoelectric effect, and on positive ionization. He returned to Britain an acknowledged authority on metallic conduction, electrons, and heal.

The move back to London in 1914 was disruptive at first, yet Richardson was able to finish his first book and to start and complete his second, The Emission of Electricity from Hot Bodies (1916). Far more disruptive were the outbreak of World War I and the demands for secret military research into telecommunications. By now Richardson’s expertise was a British asset. His reputation for having made possible the rapid development of J. A. Fleming’s “thermionic valve” connected him with the growing industries for wireless telegraphy and telephony. During the war he managed, with C. B. Bazzoni and others, to publish a few works on spectroscopy, on tests of Bohr’s theory of the atom, and on Einstein’s analysis of the photoelectric effect. Also about this time his concern with the gyromagnetic effect led to his anticipating the electron-spin momentum later attributed to G. E. Uhlenbeck and S. A. Goudsmit. In the midst of the war Wilhelm Wien even published a Richardson chapter, “Glühelektroden,” in his anthology Kanalstrahlen und Ionizations … (Leipzig, 1917).

After the war Richardson continued teaching in classroom and laboratory. In 1920 he received the Hughes Medal of the Royal Society, and in 1921–1922 he served as president of Section A (physics) of the British Association for the Advancement of Science. He relinquished all teaching duties in 1924, when he was given a dual appointment as Yarrow research professor of the Royal Society and as director for research in physics at King’s College. In 1926–1928 he served also as president of the Physical Society. On 12 December 1929 he was awarded the 1928 Nobel prize , for physics. The presentation speech stressed Richardson’s originality both in advancing a theory for the electrical conductivity of metals and in pursuing strenuously for twelve years the experimental researches necessary to verify the nature of electronic flow in and emission from glowing filaments in vacuum tubes.

“Richardson’s law,” an abstruse empirical formula that allowed him to elaborate in detail the effect of heat on the interaction between electricity and matter, was by this time widely recognized as the scientific explanation for Fleming’s rectifier and amplifier devices and for Lee de Forest’s triode and Audion, as well as for modern X-ray and cathode-ray tubes of all sorts. It is significant that Richardson had entitled his first two papers in 1901 “On an Attempt to Detect Radiation From the Surface of Wires Carrying Alternating Currents of High Frequency” and “On the Negative Radiation From Hot Platinum” (see Proceedings of the Cambridge Philosophical Society. Mathematical and Physical Sciences, 11 [1901], 168–178, and 286–295, respectively). At the beginning of the century neither the concept of the electron nor of the physical atom was fully acceptable, and Richardson’s work had centered on his intuition that both negatively and positively charged radiation emanate directly from the heated solid filaments themselves, rather than from interactions of neighboring gas molecules with hot bodies or with the electromagnetic ether.

In his Nobel acceptance lecture, “Thermionic Phenomena and the Laws Which Govern Them,” Richardson recalled his predecessors briefly and his contemporaries at length. Remembering the difficulty of his early efforts to get rid of residual gas effects (by hand pumps; through weeks of baking; without the benefit of ductile tungsten, which only became available in 1913), Richardson recounted how he had struggled from 1901 to 1911 to test and perfect his thermionic theory of electron emission. Theories of metallic conduction advanced by Thomson, Drude, and Lorentz were maturing at the same time; but the main rival to the thermionic theory was the view that these emissions were not primary physical phenomena but rather secondary chemical reactions between hot filaments and residual gases. Richardson was proud to point to 1913 as the zenith of his confidence in this research:

The advent of ductile tungsten enabled me, in 1913, to get very big currents under better vacuum conditions than had hitherto been possible and to show that the mass of the electrons emitted exceeded the mass of the chemicals which could possibly be consumed. This experiment, I think, ended that controversy so far as it could be regarded seriously [Nobel Lectures …, p. 227].

Meanwhile the progress of the rest of physics was so rapid that the canonical formulation of Richardson’s law passed through several changes in notation. It is commonly known as the Richardson-Dushman equation, after Saul Dushman (1883–1954), a Russian-American electronics expert who, beginning in 1923, reinterpreted its implications in view of Langmuir’s researches and in terms of Fermi-Dirac instead of Maxwell-Boltzmann statistics. Although Laue, Tolman, Sommerfeld, and Fowler, among others, also contributed to this ferment, Richardson himself remained acutely aware of the unsolved mysteries in electrodynamics, and he continued to lead his profession in thermionics for two decades after the quantum mechanical revolution of the 1920’s. Since his own Nobel lecture was delayed a year and thus delivered on the same day that Louis de Broglie received his 1929 prize for the wave nature of electrons, Richardson alluded to the new matter waves of de Broglie and to the new quantum mechanics as promising new ways to understand old mysteries. Yet Richardson was pleased to note that the basic equation of thermionic emission “is still valid with the magnitude of the universal constant A unaltered in any essential way” (Nobel Lectures …, p. 233). Thus, we may give Richardson’s law here as he modified it in 1911, reinterpreted it in 1915 with the universal constant A, and reexpressed it in 1929:

where i is the thermionic current density; A is a universal constant based on the mass and charge of the electron as well as Boltzmann and Planck’s constants; T is the absolute temperature in degrees Kelvin; e is the natural logarithmic base; w is a specific constant or the electronic work function of the metal used; and k is Boltzmann’s constant.

Since first suggested in 1901 and extended in 1903, this equation had been based on the simple hypothesis that freely moving electrons in the interior of a hot conductor escape when they reach the surface, if the kinetic energy of their velocity is great enough to overcome the binding forces of the material. Thus, the central idea behind this equation (“that of an electron gas evaporating from the hot source”) proved immensely fertile, suggesting all sorts of tests for electrons flowing against electromotive forces, electronic cooling of hot bodies by evaporation, and electronic heating of cool bodies independently of molecular chemical reactions. In short, Richardson said in 1929, “We could at that time [1900–1913] find out a great deal more about what the electrons in an electron gas were doing than we could about the molecules of an ordinary gas.”

Richardson always found that his facility in mathematical calculations served him in good stead. He was dexterous and soft-spoken. His patience and precautions in the laboratory taught many students of electronics not to rush to rash conclusions about mentalists’ faith that hunches for tests based on carefully controlled conditions will force nature to yield its secrets. Like Thomson, Richardson influenced a number of students and peers who became Nobel laureates, including A. H. Compton (1927), C. J. Davisson (1937), and Irving Langmuir (1932). Working with such collaborators as T. Tanaka, F. S. Robertson, P. M. Davidson, S. R. Rao, and A. K. Denisoff, Richardson’s influence spread widely around the world.

During the 1920’s and 1930’s, Richardson published about three scientific papers each year, all meticulous and treating his chief interest—trying to understand the nexus between physics and chemistry. In 1930 he received the Royal Medal of the Royal Society, and in 1932 he was invited to deliver the Silliman memorial lectures at Yale University. When the lectures were published as his third and last book, Molecular Hydrogen and Its Spectrum (1934), it quickly became a classic exposition of experimental knowledge interacting with the new theories of quantum mechanics. More than a decade of intensive studies of the diatomic hydrogen molecule as revealed by thermionic and spectroscopic techniques were codified in this work.

During his years as foreign secretary for his section of the Royal Society, Richardson often played host to visiting scholars and scientists, including Lorentz, Bohr, Planck, Debye, and Sommerfeld. Richardson talked with them about hydrogen, the simplest of all atoms and molecules; why its structure had seemed inexplicable in the old quantum theory; and how its behavior might be better described or explained either by Heisenberg’s matrix mechanics or by Schrödinger’s wave mechanics. Dirac’s theory of electrons, “holes,” and positrons seems to have been of less interest to him than the excitation of soft X rays, the emission of electrons under the influence of chemical action, and the determination of Rydberg constants. Richardson’s analyses of the multiplex lines of the H₂ spectrum and of the old question of why it happens that such an apparently simple structure should exhibit such complexity led him in 1934 to the judgment that “wave mechanics emerges triumphantly.”

In 1939 Richardson was knighted. When World War II broke out, he reduced his worldwide correspondence on behalf of physics and concentrated on radar, sonar, electronic test instruments, and associated magnetrons and klystrons.

Richardson retired from the University of London in 1944 and moved to his country house, Chandos Lodge, near Alton, Hampshire. There he and his wife gardened, ran a dairy farm, and walked in the country until her death the next year. Their elder son, Harold, had joined the physics department at Bedford College, University of London, and their younger son, John, had entered the practice of medicine and psychiatry. In 1948 Richardson married Henrietta M. G. Rupp, a distinguished physicist in her own right who had been among the first to observe electron diffraction and who was an established authority on luminescence in solids.

Richardson was awarded honorary doctorates from the universities of Leeds, St. Andrews, and London. He maintained his membership in the American Philosophical Society and was elected a foreign member of academies of science in Norway, Sweden, Germany, and India. He was chosen an honorary fellow of the Institute of Physics in 1952. After retirement to northeast Hampshire, he worked with the new large reflection echelon spectrometer, designed by W. E. Williams, and published two papers with E. W. Foster on the fine structure of hydrogen lines. Answers about the ultimate nature of hydrogen were elusive, but Richardson seems to have enjoyed the quest more than the goal. His bookplate carried the simple sign for infinity, ∞, and his collection of 2,700 books on the atom remains intact as a monument to that quest.

BIBLIOGRAPHY

I. Original Works. Richardson’s books are The Electron Theory of Matter (Cambridge, 1914; 2nd ed., 1916); The Emission of Electricity From Hot Bodies (London, 1916; 2nd ed., 1921); and Molecular Hydrogen and Its Spectrum (New Haven, 1934).

Translations and 133 major articles are listed by William Wilson: “Owen Willans Richardson, 1879–1959,” in Biographical Memoirs of Fellows of the Royal Society, 5 (1959), 207–215.

MS and memorabilia material is in the Sir Owen Richardson collection, consisting of about 25,000 items, in the Miriam Lutcher Stark Library at the University of Texas at Austin. A typescript “Catalog of the Sir Owen Richardson Collection,” compiled by James H. Leech and Dessa Ewing, was completed in 3 vols, in Nov. 1967: I, letters sent and received; II, works, including unpublished papers, notes, editions; III, miscellaneous, family letters, papers, grades, referee reports.

II. Secondary Literature. See E. W. Foster, “Sir Owen Richardson, F.R.S.,” in Nature, 183 (4 Apr. 1959), 928–929; N. H. de V. Heathcote, Nobel Prize Winners in Physics, 1901–1950 (New York, 1953), 278–286; NobelLectures—Physics, Including Presentation Speeches and Laureates’ Biographies, II, 1922–1941 (Amsterdam, 1965), 220–238; and an obituary in the Times (London) (16 Feb. 1959), 10, col. 3.

Loyd S. Swenson, Jr.