SAUNDERS, FREDERICK ALBERT

(b. London, Ontario, Canada, 18 August 1875; d. South Hadley, Massachusetts, 9 June 1963)

spectroscopy, acoustics.

Saunders was the youngest of six children born to William Saunders and Sarah Agnes Robinson Saunders, both of whom had immigrated to Canada from England. Music filled the Saunders home, and a powerful telescope and microscope provided scientific entertainment for the entire family. William Saunders, a druggist, managed a pharmaceutical company and an experimental farm near London, Ontario. In 1886 the family moved to a farm near Ottawa, from which the elder Saunders directed a system of government-sponsored experimental farms throughout Canada.

Frederick Saunders attended school in London and Ottawa. He entered the University of Toronto intending to study chemistry, but soon transferred to physics. After receiving the bachelor of arts degree in 1895, he entered the doctoral program in physics at Johns Hopkins University, where he studied under Henry A. Rowland, a leading American spectroscopist.

Spectroscopy at that time offered insights into two significant fields of research: blackbody radiation and atomic structure. When heated, perfectly absorbing blackbodies emit heat radiation at energy intensities that form a characteristic curve (at each temperature) as a function of emitted frequencies. Saunders’ dissertation, completed in 1899, involved experimental tests of available expressions for this curve for temperatures below 500°C. The results, not published until 1901, showed major deviations from Wilhelm Wien’s distribution law, similar to those obtained in 1900 by experimenters at the Imperial Physical-Technical Institute in Berlin who included Heinrich Rubens, Ferdinand Kurlbaum, and Ernst Pringsheim. The latter prompted Max Planck’s hypothesis of the correct distribution law and the notion of energy quanta.

After receiving his doctorate Saunders taught physics at Haverford College for two years and then transferred to Syracuse University, becoming full professor in 1905. In 1900 he married Grace A. Elder, with whom he had a son and a daughter. He married Margaret Tucker in 1925.

At Syracuse, Saunders turned to atomic spectroscopy. He utilized the concave grating method developed by Rowland to obtain the spectra of the alkali metals (such as lithium, sodium, and potassium) and the alkaline earths (magnesium, calcium, barium), grouping the observed frequencies into series. In 1904 he discovered several lines of the subsequently well-known “fundamental series”.

A sabbatical year, 1913-1914, enabled Saunders to visit European laboratories. He worked at Tübingen and was greatly impressed by Friedrich Paschen, a foremost spectroscopist and a skillful administrator. After returning to the United States, Saunders was appointed professor of physics at Vassar College. He pursued refined spectroscopic analyses learned in Tübingen and examined data supplied by his former Tübingen colleagues.

U.S. entry into World War I interrupted Saunders’ research. In 1917 he joined scientists at Princeton University who were developing methods of sound ranging. Among the group was his later collaborator, the Princeton astronomer Henry Norris Russell. In 1918 Saunders moved to Washington, where he tested the military feasibility of new optical devices. Following the war he served on the National Research Council committees on spectroscopy and atomic structure.

In 1919 Theodore Lyman invited Saunders to fill a vacant position in the department of physics at Harvard University. Besides modernizing the introductory physics course, which he taught until his retirement in 1941, Saunders succeeded Lyman as department chairman in 1926, a post he also held until shortly before his retirement.

Saunders is most remembered for his work with Russell. The 1922 discovery of multiplet spectra brought a new challenge to atomic physics. Russell, according to Saunders, found a theoretical account of the effect for alkaline earths, while Saunders provided most of the experimental data. During the period 1923 to 1925 Russell and Saunders extended Alfred Landé’s vector atomic model by hypothesizing that the orbital angular momenta of the two valence electrons couple together to form a resultant (L) that interacts with the angular momentum of the core (the Rumpf) to generate complex energy levels that in turn yield the multiplet spectra. Later identification of the core momentum with the resultant electron spin (S) led to modern L-S or “Russell-Saunders” coupling.

After several studies with Lyman of noble-gas spectra, Saunders turned to teaching, administration, and the field of musical acoustics. With the formulation of quantum mechanics and the discovery of electron spin, the heyday of atomic spectroscopy had ended by 1927. With funds provided by Henry S. Shaw, a Boston philanthropist, Saunders, an accomplished violinist, used modern techniques to examine the tonal qualities of violins. The pioneering research followed three methods: the harmonic analysis of each note, using an acoustic analyzer; comparative curves of total sound intensity, using a sound meter; and electromagnetic analysis of vibrations, using an oscilloscope. The results were surprising. Comparison of the best antique and modern instruments showed little tonal difference. Any advantage of the older instruments lay in their more rapid response to movements of the bow, often essential for complicated pieces.

As a charter member and later president (1937-1939) of the Acoustical Society of America, Saunders brought his research to wider circles. Following his retirement from Harvard, he became visiting lecturer at Ml. Holyoke College, where he established an acoustics laboratory. Collaboration with A. S. Hopping, an electronics engineer, and Carleen M. Hutchins, a constructor of violas, led to more sophisticated studies of instrument construction. Beginning in 1948, at the urging of Henry Brandt, composer-in-residence at Bennington College, Hutchins and Saunders invented and constructed a new “family of fiddles”, consisting of eight physically similar stringed instruments ranging between the treble violin and large bass. Although the success of the experiment is still in question, musicians remain favorably intrigued.

Saunders continued to study and play stringed instruments to the end of his life. He also pursued his interests in ornithology, becoming a recognized authority on the identification and behavior of birds. He served from 1952 until his death as an honorary vice president of the Massachusetts Audubon Society.

BIBLIOGRAPHY

I. Original Works. Saunders published most of his papers on spectroscopy in Astrophysical Journal; most of his work on acoustics appeared in Journal of the Acoustical Society of America. A bibliography of most of his publications is in Harry F. Olson, “Frederick Albert Saunders”, in Biographical Memoirs, National Academy of Sciences, 39 (1967), 403-416. Omissions from the list include “Some Additions to the Arc Spectra of the Alkali Metals”, in Astrophysical Journal, 20 (1904), 188-201; “On the Spectra of Neon and Argon in the Extreme Ultraviolet”, in Nature, 116 (1925), 358, written with Theodore Lyman; and “Physics and Music”, in Scientific American, 179 (July 1948), 32-41. Manuscript sources include Saunders’ membership file for the National Academy of Sciences and the papers of committees of the National Research Council’s Division of Physical Sciences, all in the archive of the National Academy of Sciences, Washington, D.C. Scattered correspondence may be located through the Inventory of Sources for Twentieth-Century Physics, University of California, Berkeley.

II. Secondary Literature. The most complete biographical notice is by Harry A. Olson, cited above. Obituaries were published in the New York Times, 10 June 1963, 31, and Physics Today, 16 (August 1963), 74. An account of the Saunders family is Elsie Pomeroy. William Saunders and His Five Sons (Toronto, 1956), Some details about Harvard physics may be gleaned from the annual Harvard University Catalogue and the annual Harvard University, President’s Report. Historical works on spectroscopy include Paul Forman, “Alfred Landé and the Anomalous Zeeman Effect, 1919-1921”, in Historical Studies in the Physical Sciences, 2 (1970), 153-261; Hans Kangro, Early History of Planck’s Radiation Law, R, E. W. Maddison, trans. (London, 1976); and J. H. Van Vleck, “Quantum Principles and Line Spectra”, National Research Council Bulletin, 10 (1926). For discussions of Saunders’ acoustical research, see Carleen Maley Hutchins, “The Physics of Violins”, in Scientific American, 206 (November 1962), 78-93; and Lothar Cremer, The Physics of the Violin, John S. Allen, trans. (Cambridge, Mass., 1984), 352-356.

David C. Cassidy