Frost, Edwin Brant

(b. Brattleboro, Vermont, 14 July 1866; d. Chicago, Illinois, 14 May 1935)

astronomy.

The second son of Carlton Pennington Frost and Eliza Ann DuBois, Frost spent most of his youth at Hanover, New Hampshire, where his father held a professorship in medicine at Dartmouth College and was later dean of the medical school. He was much influenced by the astronomer C. A. Young. Frost’s early education was at home, his first experience of a formal classroom being at the age of eleven. He graduated from Dartmouth in 1886 with honors in physics. After remaining at Dartmouth a few months to do graduate work in chemistry, Frost taught for a term in Hancock, New Hampshire. He spent the spring of 1887 learning practical astronomy under Young at Princeton and in the autumn returned to Dartmouth as instructor in physics and astronomy. In 1890 he left for two years’ study in Europe, first for a semester at the University of Strasbourg and then with H. C. Vogel at the Potsdam Observatory. Frost returned to Dartmouth as assistant professor in astronomy, being promoted to full professor in 1895. In 1896 he married Mary Elizabeth Hazard. In 1898 he became professor of astrophysics at the new Yerkes Observatory, although he continued to spend part of his time teaching at Dartmouth until 1902. He succeeded Hale as director of the Yerkes Observatory in 1905, a position he held until 1932.

In 1915, while observing with the forty-inch telescope at Yerkes, his right retina became detached, and vision with this eye was completely lost within a year. A cataract developed in his left eye, and a hemorrhage occurred a few years later. Almost total blindness was only a minor inconvenience to him; if he had not been so afflicted, he would probably not have discovered that one can determine the temperature (in degrees Fahrenheit) by counting the number of chirps of the snowy tree cricket (Oecanthus niveus) in thirteen seconds and adding forty-two.

It was during his stay at Potsdam that Frost became involved in stellar spectroscopy, and the appearance of the nova T Aurigae (1891) prompted him to obtain photographs of the spectrum of this and other stars. On returning to Dartmouth he published under the title A Treatise on Astronomical Spectroscopy (1894) a translation and revision of Scheiner’s Die Spectralanalyse der Gestirne; this was a standard text for many years. He made routine solar, cometary, and meteorological observations and participated in some of the first X-ray experiments outside Europe; he also made a qualitative study of the spectrum of Beta Lyrae (1895). At the 1900 eclipse he obtained photographs of the flash spectrum and also of the spectrum of the corona. He secured spectrograms of Comet Morehouse 1908 III and nova DI Lacertae 1910. He edited the extensive series of solar observations by C. H. F. Peters (1906) and subsequently Barnard’s micrometric measurements of star clusters (1931).

Frost’s principal research field, however, was stellar spectroscopy, specifically the determination of radial velocities of stars and especially stars of early spectral type. By 1895 radial velocities had been determined for only fifty stars. Soon after arriving at Yerkes, Frost designed for the forty-inch refractor the Bruce spectrograph; it is in no small measure due to the observations by Frost and his colleagues with this instrument that the number of stars whose radial velocities were known increased more than a hundredfold during the following forty years. Frost was the first to realize that there are systematic differences between the velocities of stars of different spectral types. He early recognized the need for calibrating the results obtained with different instruments and by a variety of methods. A natural outcome of radial velocity studies is the discovery of spectroscopic binaries; this is particularly true for stars of early spectral type, of which Frost found and determined the orbits of a considerable number.

Frost received honorary D.Sc. degrees from Dartmouth (1911) and Cambridge (1912). He was an associate of several foreign astronomical societies. He served as an assistant editor of the Astrophysical Journal from its inception in 1895 and as an editor from 1902 until his death.

BIBLIOGRAPHY

I. Original Works. Frost’s works include A Treatise on Astronomical Spectroscopy (Boston, 1894), a trans. and rev. of J. Scheiner’s Die Spectralanalyse der Gestirne; “Spectroscopic Observations of Standard Velocity Stars,” in Astrophysical Journal, 18 (1903), 237–277, written with W. S. Adams; “Radial Velocities of Twenty Stars Having Spectra of the Orion Type,” in Publications of the Yerkes Observatory, 2 (1904), 145–250, written with W. S. Adams; “Radial Velocities of 368 Helium Stars,” in Astrophysical Journal, 64 (1926), 1–77, written with S. B. Barrett and O. Struve; “Radial Velocities of 500 Stars of Spectral Class A,” in Publications of the Yerkes Observatory, 7 (1929), 1–79, written with S. B. Barrett and O. Struve; and An Astronomer’s Life (Boston-New York, 1933).

II. Secondary Literature. An obituary notice by P. Fox appeared in Astrophyscial Journal, 83 (1936), 1–9.

Brian G. Marsden