Midgley, Thomas, Jr.

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(b. Beaver Falls, Pennsylvania, 18 May 1889; d. Worthington, Ohio, 2 November 1944)


Midgley was the son of Thomas Midgley, a successful inventor, and Hattie Lena Emerson. Following graduation from Betts Academy, he entered Cornell University where he took the course in mechanical engineering; he graduated in 1911. His subsequent work, however, lay in industrial chemistry, to which he brought a mastery of scientific fundamentals and a talent for ingenious experimentation.

In 1916, shortly after he had joined Charles F. Kettering’s Dayton Engineering Laboratories, Midgley was assigned the problem of reducing internalcombustion knock. Gaseous detonation, or knock, was obstructing the development of Kettering’s Delco engine; the phenomenon was only imperfectly understood, and was initially attributed to the ignition of the battery employed in Kettering’s self-starting device for automobiles. From 1917 until 1921, Midgley used a variety of experimental techniques directed toward finding a chemical antiknock agent.

Midgley and Kettering assumed that knock was an inverse function of volatility. They first tried iodine as a fuel additive, supposing that a red dye might cause low-volatility fuel to absorb radiant heat and citing the example of the red-backed trailing arbutus that blooms under snow. They found that knocking did decrease greatly, although further tests demonstrated that the red color was inconsequential. They had nonetheless shown that a chemical antiknock agent does exist; since iodine proved impractical as a fuel additive, Midgley undertook to test at least one compound of each chemical element in an attempt to find something better. After months of research he established that aniline and its homologues—as well as other nitrogenous compounds—are effective chemical agents, but that they also give off an unbearable smell.

Midgley then began to make use of Robert E. Wilson’s arrangement of the periodic table, which was based on Langmuir’s theory of atomic structure and chemical valence. He employed a bouncing-pin indicator to measure knock quantitatively, then correlated these measurements with the table to establish trends; he thus discovered the antiknock properties of lead and, on 9 December 1921, singled out the remarkable effectiveness of tetraethyl lead. Added to gasoline, tetraethyl lead improved the engine compression ratio, thereby economizing fuel. The substance was put into large-scale production after a number of difficulties had been overcome, including a moratorium placed upon its use to allow a U. S. surgeon general’s committee to investigate any possible danger of widespread lead poisoning. Midgley was then appointed general manager of the Ethyl Gasoline Corporation.

In 1930 Kettering, who was in charge of research at General Motors, asked Midgley to find a nontoxic, nonflammable, and cheap refrigerant for use in household appliances. Again drawing upon the periodic table, Midgley discovered dichlorodifluoromethane within three days, a compound that possessed all the desired qualities. He was less successful in his investigations of natural and synthetic rubber, however. These constitute the most purely scientific of his works.

Midgley recehed the four principal American medals for achievement in chemistry: the Nichols Medal (1922), the Perkin Medal (1937), the Priestley Medal (1941), and the Willard Gibbs Medal (1942). He was president of the American Chemical Society; in his presidential address to that body, delivered only a few months before he died, he suggested that scientists older than forty should remove themselves from positions requiring a high order of creativity, since he thought that most of the great discoveries and inventions had been made by workers between the ages of twenty-five and forty-five.


I. Original Works. Two articles indicative of Midgley’s formal and informal communications are, respectively, “The Chemical Control of Gaseous Detonation With Particular Reference to the Internal-Combustion Engine,” in Journal of Industrial and Engineering Chemistry, 14 (1922), 894–898, written with T. A. Boyd; and “From the Periodic Table to Production,” ibid., 29 (1937), 241–244.

II. Secondary Lierature. Biographical essays on Midgley include one by his mentor, professional associate, and friend, Charles F. Kettering: “Biographical Memoir of Thomas Midgley, Jr.,” in Biographical Memoirs. National Academy of Sciences,24 (1947), 361–380, which includes a list of 57 articles by Midgley but does not list his patents. An extremely useful essay is by Midgley’s close research associate, T. A, Boyd: “Thomas Midgley, Jr.,” in Journal of the American Chemical Society, 75 (1953), 2791–2795, abo with a list of articles, Williams Haynes, the historian of the American chemical industry, has written an essay on Midgley in Great Chemists, Eduard Farber, ed. (New York, 1961), 1589–1597, On Midgley’s work, especially the history of tetraethyl lead, see T. A. Boyd, “Pathfinding in Fuels and Engines,” in S.A.E. Quarterly Transactions, 4 (1950}, 182–185; and Professional Amateur; The Biography of Charles Franklin Kettering (New York, 1957); and Williams Haynes, American Chemical Industry, IV (New York, 1948).

Thomas Parke Hughes