Tolman, Richard Chace
TOLMAN, RICHARD CHACE
(b.West Newton, Massachusetts, 4 March 1881; d. Pasadena, California, 5 September 1948),
Physical chemistry, mathematical physics.
Tolman came from a prosperous New England family with close ties to the business and academic world. Following in his father’s footsteps, Tolman enrolled at the Massachusetts Institute of Technology after attending the public schools in West Newton. He received a bachelor of science degree in chemical engineering in 1903. He spent the following year in Germany, at the Technische Hochschule at Charlottenburg, and later at Crefeld in an industrial chemical laboratory. Upon his return to M.I.T. in 1904 as a graduate student, Tolman joined Arthur Amos Noyes’s Research Laboratory of Physical Chemistry and earned his Ph.D. in 1910. Tolman taught briefly at the University of Michigan and the University of Cincinnati before going to the University of California, Berkeley (1912–1916). He became professor of physical chemistry at the University of Illinois in 1916.
In Washington, D.C., i 1918, while serving as chief of the dispersoid section of the Chemical Warfare Service, Tolman crossed paths again with Noyes, then chairman of the Committee on Nitrate Supply. Noyes was already working hard to persuade the government to continue after the war its research program on the nitrogen products used in explosives and fertilizers. His efforts led to the creation of the Fixed Nitrogen Research Laboratory in 1919, and to Tolman’s appointment as associate director (1919–1920) and director (1920–1922). The laboratory flourished under Tolman’s direction, and became a mecca for bright young physical chemists. In 1922 Tolman joined the faculty of the California Institute of Technology through Noyes’s efforts. As professor of physical chemistry and mathematical physics, Tolman served as dean of the graduate school and was a member of the executive council for many years.
The main thrust of Tolman’s work in statistical mechanics, relativistic thermodynamics, and cosmology was mathematical and theoretical. His earliest scientific research (1910) involved measuring the electromotive force produced when a centrifugal force is applied to an electrolytic solution. Tolman based the derivation of an expression for the electromotive force on kinetic arguments, in addition to the customary thermodynamic ones, and showed that both yield the same equation. Turning to metallic conductors next, Tolman, working with T. Dale Stewart at Berkeley, demonstrated the production of an electromotive force by measuring the flow of electric current when a coil of wire rotating about its axis is mechanically accelerated and then brought to a sudden halt. In 1916 they made the first laboratory determination of the mass of the electric carrier in metals.
Tolman also published a number of important papers in the field of chemical kinetics in gaseous systems, that is, the problem of accounting for the rate at which chemical reactions take place. His theoretical treatment of monomolecular thermal and photochemical reaction rate underscored the need to clarify the meaning of the loosely defined concept of the energy of activation. This done, Tolman turned to the experimental work of Farrington Daniels and his co-workers on the decomposition of nitrogen pentoxide, the best example of a first-order unimolecular reaction over a range of concentrations and at a series of temperatures, as a check on the proposed mechanisms of chemical reaction then current. In particular, he showed in 1925 that the simple radiation theory of reaction proposed by Jean Baptiste Perrin and W. C. McC. Lewis did not adequately account for known rates of reaction. The papers not only reveal Tolman’s precise reasoning and great physical intuition, but also his consuming interest in the application of statistical mechanics to rates of physical–chemical change.
With Gilbert N. Lewis, Tolman published the first American exposition of the special theory of relativity in 1909. Tolman later wrote The Theory of the Relativity of Motion (Berkeley, 1917). This early interest in relativity theory was further stimulated by Hubble’s discovery in 1929 that red shifts are proportional to distance, and led to a series of studies on the applications of the general theory to the overall structure and evolution of the universe. In his comprehensive treatise on relativistic thermodynamics, Tolman presented his theory of a universe expanding and contracting rhythmically like a beating heart, arguing that gravity has the effect of counteracting the influence of radiation, thus preventing the complete cessation of motion as predicted by the second law of thermodynamics.
During World War II, Tolman served as vicechairman of the National Defense Research Committee, as scientific adviser to General Leslie R. Groves on the Manhattan Project, and as United States adviser to the wartime Combined Policy Committee. Afterwards, he became scientific adviser to Bernard Baruch on the United Nations Atomic Energy Commission. Honors received during his lifetime included the Medal for Merit and election to the National Academy of Sciences in 1923.
Tolman married Ruth Sherman, a psychologist, in 1924. They had no children. He willed the bulk of his estate to the California Institute of Technology.
Tolman published four books and over 100 scientific papers, all of which are chronologically listed in the bibliography appended to the biographical introduction prepared by J. G. Kirkwood, O. R. Wulf, and P. S. Epstein, in Biographical Memoirs, National Academy of Sciences, 27 (1952), 139–153. In Principles of Statistical Mechanics (Oxford, 1938), a monograph that remains a classic in its field, Tolman refashioned statistical mechanics by using quantum rather than classical mechanics as the starting point for the science. Details about his family and childhood can be gleaned from his brother’s autobiographical notes, found in B. F. Ritchie, “Edward Chace Tolman,” ibid., 37 (1964), 293–324. Bernard Jaffe, Outposts of Science (New York, 1935), 506–516, gives a vivid picture of Tolman’s work in cosmology at Caltech in the 1930’s. His World War II activities are thoroughly covered in Albert B. Christman’s Sailors, Scientists and Rockets, I (Washington, D. C., 1971).
Manuscript sources include letters in the papers of Gilbert N. Lewis, now in the office of the Chemistry Department, Berkeley, and Several boxes of correspondence and unpublished manuscripts in the archives of the California Institute of Technology.
Judith R. Goodstein