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Richtmyer, Floyd Karker


(b. Cobleskill, New York, 12 October 1881; d. Ithaca, New York, 7 November 1939), physics.

Richtmyer’s chief contributions to science were his enthusiastic teaching of physics, his zeal for administration in the community of physicists, and his experimental researches in X-ray spectra. He was brought up in the country, where he attended local public schools. After receiving the Ph.D. at Cornell University in 1910, he remained on the physics staff there until his death, becoming a full professor in 1918 and dean of the graduate school in 1931.

Richtmyer’s first researches were in photometry, specifically, the application of photoelectricity to this field. After 1918, however, he turned his attention to X-ray spectroscopy and worked in this domain for the rest of his life. He became particularly interested in low-intensity satellite lines in X-ray spectra and developed high-precision methods for studying them. This research led to a broader program of investigation of widths and shapes of X-ray lines and absorption limits. This program was carried on at Cornell for many years, largely by Richtmyer’s graduate students under his guidance.

Richtmyer’s interest in teaching is reflected not only in the courses he gave and in his supervision of graduate students but also in his celebrated book, Introduction to Modern Physics (1928), which had considerable influence on the teaching of atomic physics and, with revisions and additions by colleagues after his death, remained a valuable work.

Richtmyer devoted much attention to professional societies and served as president of the American Physical Society, the Optical Society of America, and the American Association of Physics Teachers. In 1932 he was elected a member of the National Academy of Sciences. For several years he was also a member of the executive committee of the American Institute of Physics and was a long-time editor of the Review of Scientific Instruments. All who met Richtmyer were impressed with his active and unselfish devotion to the advancement of the profession of physics.


I. Original Works. Richtmyer’s complete bibliography includes one book and seventy-three articles. A complete list is given by Ives, below. His book is Introduction to Modern Physics (New York, 1928). His major articles include “Dependence of Photoelectric Current on Light Intensity,” in Physical Review, 29 (1909), 71–78; “Photoelectric Effect With Alkali Metals. II,” ibid., 404–408; “Photoelectric Cells in Photometry,” in Transactions of the Illuminating Engineering Society, 8 (New York, 1913), 459–469; “Comparison of Flicker and Equality-of-Brightness Photometer,” in Bulletin of the Bureau of Standards, 14 (1918), 87–113, written with E. C. Crittenden; “The Mass-Absorption Coefficient of Water, Aluminum, Copper and Molybdenum for X-rays of Short Wavelength,” in Physical Review, 15 (1920), 547–549, written with Kerr Grant; “Absorption of X-rays,” ibid., 18 (1921), 13–30; and “The Size of the Electron as Determined by the Absorption and Scattering of X-rays,” ibid., 20 (1922), 87–88.

Subsequent writings include “The Structure of the K Lines of Molybdenum,” ibid., 23 (1924), 550–551, written with R. C. Spencer; “The Apparent Shape of X-ray Lines and Absorption Limits,” ibid., 26 (1925), 724–735; “Absorption of X-rays in Various Elements,” in Nature, 120 (1927), 915–916; “Multiple Ionisation and Absorption of X-rays,” in Philosophical Magazine, 6 (1928), 64–88; “Satellites of X-ray Lines Lα, Lβ1, and Lβ2,” in Physical Review, 34 (1929), 574–581, written with R. D. Richtmyer; “Hyperfine Structure of X-ray Lines,” ibid., 36 (1930), 1017, written with S. W. Barnes and K. V. Manning; “Intensity of X-ray Satellites,” ibid., 36 (1930), 1044–1049, written with L. S. Taylor; “X-rays and Their Uses,” in Scientific Monthly, 32 (1931), 454–463; and “The Romance of the Next Decimal Place,” in Science, 75 (1932), 1–5.

Later works are “Relative Intensities of Certain L-series X-ray Satellites in Cathode-ray and in Fluorescence Excitation,” in Physical Review44 (1933), 955–960. written with F. R. Hirsh, Jr.; “The Widths of the L-series Lines and of the Energy Levels of Au(79).” ibid., 46 (1934), 843–860, written with S. W. Barnes and E. Ramberg; “Determination of the Shape, Wavelength and Widths of an X-ray Absorption Limit,” ibid., 43 (1933), 754, written with S. W. Barnes; “L-satellites in the Atomic Number Range 73 < Z < 79,” ibid., 51 (1936), written with C. H. Shaw and R. E. Shrader; and “Determination of Widths of Energy States: Argon K Absorption Limit,” ibid., 52 (1937), 678–679, written with L. G. Parratt.

II. Secondary Literature. On Richtmyer and his work, see Herbert E. Ives, “Floyd Karker Richtmyer 1881–1939,” in Biographical Memoirs. National Academy of Sciences, 22 (1941), 71–81, with portrait and bibliography; and F. R. Hirsh’s notice in Dictionary of American Biography, XXII. supp. 2 (New York, 1958), 556–557.

R. B. Lindsay

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