Keeler, James Edward

(b. La Salle, Illinois, 10 September 1857; d. San Francisco, California, 12 August 1900)

astronomy.

When he died at the age of forty-two, Keeler was the leading astrophysicist in the United States. He is best remembered today for his spectroscopic proof that the rings of Saturn are composed of small particles moving independently, and for his discovery of the abundance of spirals among the nebulae.

His father was William F. Keeler, who served as a paymaster in the U.S. Navy during the Civil War; his mother, Anna, was the daughter of Henry Dutton, onetime governor of Connecticut. Keeler attended public schools in La Salle until 1869, when the family moved to Mayport, Florida. In this small settlement a few miles east of Jacksonville, Keeler helped his father and older brother to build the house they lived in. He had no formal secondary education. At age eighteen, Keeler sent away for two lenses and made a telescope. This was the beginning of his “Mayport Astronomical Observatory”; other equipment included a quadrant, chronometer, and meridian circle—all homemade.

Providentially, Charles H. Rockwell, of Tarrytown, New York, learned of Keeler’s interest in astronomy and made it possible for him—by then twenty years old—to enroll as a freshman at the newly opened Johns Hopkins University in Baltimore, Maryland. Keeler earned part of his expenses there as assistant to Charles S. Hastings, professor of physics, and with him took part in the U.S. Naval Observatory expedition to Central City, Colorado, to observe the solar eclipse of 29 July 1878.

Upon receiving his B.A. degree in June 1881, Keeler went to Pittsburgh, Pennsylvania, as assistant to Samuel P. Langley, who was then director of the Allegheny Observatory. Keeler arrived just in time to take part in the expedition to Mount Whitney, California (July, 1881), when Langley’s new bolometer was used to measure the infrared radiation of the sun.

In 1883 Keeler went abroad for a year, to study at Heidelberg under G. H. Quincke and at the University of Berlin under H. L. F. von Helmholtz. He then returned to Allegheny, to remain until 1886, when he became the first professional astronomer to reside on Mount Hamilton, where the Lick Observatory was under construction; his main job was to set up a time service for distribution from there to various commercial interests.

When the University of California took formal possession of Lick in 1888, Keeler remained, with the title of astronomer. Here it was that he used the thirty-six-inch refracting telescope and a spectroscope incorporating one of Henry A. Rowland’s concave gratings to measure (1890) the wavelengths of the bright lines in nebular spectra. His accuracy was sufficient to show that—like stars—gaseous nebulae have measurable motions toward or away from the earth. The precision of these measurements also helped to show that some of the wavelengths did not correspond to any atomic transitions known to occur on earth; this led to Keeler’s involvement in the early stages of the “nebulium” controversy, which was finally resolved by Ira S. Bowen in 1927.

In June of 1891 Keeler married Cora Slocomb Matthews, niece of the president of the Lick board of trustees. That same year he left Lick for seven years, having been appointed successor to Langley as director of the Allegheny observatory. Langley had become secretary of the Smithsonian Institution. During this period of his life Keeler designed a spectrograph—differing from a spectroscope in that spectral lines are recorded photographically rather than being located by eye—and with it obtained (1895) the classic proof of James Clerk Maxwell’s theoretical prediction that the rings of Saturn are meteoritic in nature.

Returning to Lick in 1898 to succeed Edward S. Holden as director, Keeler was able to put into use the thirty-six-inch Crossley reflecting telescope, which had defied earlier astronomers (it was difficult to operate because of an unusual mounting, designed, furthermore, for its original location in England). With the Crossley, Keeler took a series of photographs that revealed how greatly spiral nebulae—later identified as exterior galaxies—outnumbered all the other hazy objects detectable in the sky. He was awaiting the completion of a slitless spectrograph he had designed for use with this telescope when he had a heart attack and died.

Keeler was granted an honorary Sc.D. by the University of California in 1893. He was elected a fellow and foreign associate of the Royal Astronomical Society (London) in 1898, and awarded the Rumford Medal of the American Academy of Arts and Sciences that same year, for his applications of spectroscopy to astronomy. On the same basis he received the Henry Draper medal from the National Academy of Sciences in 1899 and was elected to membership in 1900. He was coeditor with George Ellery Hale of the Astrophysical Journal from its inception.

BIBLIOGRAPHY

I. Original Works. Abstracts from Keeler’s “Records of Observations Made at the Mayport Observatory” are included in the second obituary notice by Campbell (see below); the original work seems to have disappeared.

Keeler’s first published work, a description of the solar corona during the eclipse of 29 July 1878, appeared as “Addendum E of Appendix III,” to Astronomical and Meteorological Observations Made During the Year 1876 at the U.S. Naval Observatory (Washington, 1880), pp. 170–173; his second work, describing what he saw during the transit of Venus on 5 December 1882, was “The Ring of Light Surrounding Venus,” in Sidereal Messenger, 1 (1882–1883), 292–294.

Products of Keeler’s early days at Lick were “The Time Service of the Lick Observatory,” ibid., 6 (1887), 233–248; and “First Observations of Saturn With the 36-Inch Equatorial of Lick Observatory,” ibid., 7 (1888), 79–83; the latter records the very first use of that great refracting telescope.

Keeler’s second solar eclipse expedition was one he led from Lick to Bartlett Springs, California; it is described in “Total Eclipse of the Sun of January 1, 1889,” in Contributions From the Lick Observatory, 1 , pt. 2 (1889), 31–55. His work on the radial velocities of nebulae with bright line spectra appeared as “On the Motions of the Planetary Nebulae in the Line of Sight,” in Publications of the Astronomical Society of the Pacific, 2 (1890), 265–280, with an expanded version, “Spectroscopic Observations of Nebulae,” in Publications of the Lick Observatory, 3 (1894), 161–229. Criticism of these results can be found in the verbatim account of the Royal Astronomical Society’s meeting of 8 May 1891, in Observatory, 14 (1891), 209–213; for Keeler’s reply, see “Elementary Principles Governing the Efficiency of Spectroscopes for Astronomical Purposes,” in Sidereal Messenger, 10 (1891), 433–453.

While he served as director of the Allegheny observatory, Keeler published forty-eight papers, including “Physical Observations of Mars, Made at the Allegheny Observatory in 1892,” in Memoirs of the Royal Astronomical Society, 51 (1892–1895), 45–52, with 12 sketches tipped in: “A Spectroscopic Proof of the Meteoritic Constitution of Saturn’s Rings,” in Astrophysical Journal, 1 (1895), 416–427; and “The Importance of Astrophysical Research and the Relation of Astrophysics to the Other Physical Sciences [Address Delivered at the Dedication of Yerkes Observatory, 21 Oct. 1897],” ibid., 6 (1897), 271–288, reprinted in Science, n.s. 6 (19 Nov. 1897), 745–755; this address provides a good summary of the current state of astrophysics and also displays the clarity of Keeler’s thinking.

Among Keeler’s publications while director of Lick are “The Crossley Reflector of the Lick Observatory,” in Astrophysical Journal11 (1900), 325–349, reprinted in Publications of the Astronomical Society of the Pacific, 12 (1900), 146–167, and also in Publications of the Lick Observatory, 8 (1908), see below; and “Photograph of the Trifid Nebula, in Sagittarius,” in Publications of the Astronomical Society of the Pacific, 12 (1900), 89–90, with photogravure repro. facing p. 89. Keeler’s program for work with the Crossley was completed after his death by Charles Dillon Perrine and appeared as “Photographs of Nebulae and Clusters, Made with the Crossley Reflector, by James Edward Keeler, Director of the Lick Obervatory, 1898–1900.” in Publications of the Lick Observatory, 8 (1908), 1–46, followed by 70 plates.

A list of 126 publications by Keeler is included in Campbell’s first obituary notice and reprinted in Hastings’ biographical memoir (see below for both).

II. Secondary Literature. Charles Sheldon Hastings wrote the entry on Keeler in Biographical Memoirs. National Academy of Sciences, 5 (1905), 231–246, which includes a portrait facing p. 231 and a list of publications, pp. 241–246. This memoir is based on obituaries by John Alfred Brashear (covering Keeler’s days at Allegheny) in Popular Astronomy, 8 (1900), 476–481; William Wallace Campbell (Lick) in Astrophysical Journal, 12 (1900), 239–253, including a list of publications; and George Ellery Hale in Science, n.s. 12 (1900), 353–357, reminiscences of their long association.

Other obituaries are those by William Wallace Campbell, in Publications of the Astronomical Society of the Pacific, 12 (1900), 139–146, with excerpts from the Mayport Observatory records; and by Charles Dillon Perrine in Popular Astronomy, 8 (1900), 409–417.

Sally H. Dieke