Comstock, George Cary

(b. Madison, Wisconsin, 12 February 1855; d. Madison, 11 May 1934),

astronomy.

Comstock was the eldest son of Charles Henry and Mercy Bronson Comstock, an itinerant Midwestern family. His education, not atypical for his time, gave him a working knowledge of several fields of endeavor. While a student at the University of Michigan (1873–1877) Comstock was encouraged by James C. Watson to take his course in astronomy. To support his college career Comstock worked each summer, and for a year following his graduation, as recorder and assistant engineer on the U.S. Lake Survey; this practical fieldwork was later put to use in his teaching and in his textbooks. Some time later, to guard against the possibility that astronomy might not provide an adequate living, Comstock studied law, graduating from the University of Wisconsin law school (1883) and being admitted to the bar.

Astronomy, however, did become profitable. In 1879 Comstock moved to Madison, as assistant to Watson, who had recently been appointed the first director of the new Washburn Observatory of the University of Wisconsin; and, except for a brief stint teaching mathematics at Ohio State University (1885–1886) and a summer at the Lick Observatory (1886), Comstock spent the remainder of his scientific career at Wisconsin. He was elected to membership in the National Academy of Sciences (1899), the American Academy of Arts and Sciences, and the Astronomische Gesellschaft; for ten years he was first secretary of the American Astronomical Society and, in 1894, vice-president of the American Association for the Advancement of Science.

By all accounts Comstock was known as an excellent teacher and administrator. His varied teaching duties were directed toward undergraduate and graduate astronomy students, all civil engineering students, and, during World War I, prospective mariners needing knowledge of navigation techniques. In connection with teaching Comstock wrote four textbooks: An Elementary Treatise Upon the Method of Least Squares (1890), giving a working rather than an analytical knowledge of the subject; A Text-book of Astronomy (1901), for high school students; A Text-book of Field Astronomy for Engineers (1902); and The Sumner Line (1919). At the University of Wisconsin, Comstock held numerous administrative posts, including chairman, director, and dean of the graduate school.

Comstock’s two major scientific researches were primarily visual observational, in the area of precise position measurements; he pursued both problems assiduously for several decades. The first involved a redetermination of the constants of aberration and of atmospheric refraction. Although he did not derive new values for these constants, Comstock was able to verify, or support, Struve’s value for aberration and the Pulkovo tables for refraction. He then simplified the formula for atmospheric refraction, producing a formula useful for general work if not for observations of the highest possible precision. Comstock’s second investigation, concerning double stars, demonstrated the existence of relatively large proper motions for apparently faint (twelfth magnitude) stars—a question then much in doubt. He finally concluded, as is now well accepted, that there are a large number of intrinsically faint stars in the neighborhood of the sun.

BIBLIOGRAPHY

Comstock’s textbooks are An Elementary Treatise Upon the Method of Least Squares, With Numerical Examples of Its Applications (Boston, 1890); A Text-book of Astronomy (New York, 1901); A Text-book of Field Astronomy for Engineers (New York, 1902; 2nd ed., rev, and enl., New York, 1908); and The Sumner Line; or, Line of Position as an Aid to Navigation (New York, 1919).

A bibliography of Comstock’s writings is in Joel Stebbins, “Biographical Memoir of George Cary Comstock, 1855–1934,” in National Academy of Sciences. Biographical Memoirs, 20 (1939), 161–182.

Deborah Jean Warner