Sampson, Ralph Allen

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SAMPSON, RALPH ALLEN

(b. Skull, County Cork, Ireland, 25 June 1866; d. Bath, England, 7 November (1939)

astronomy.

Sampson studied at St. John’s College, Cambridge, and in 1888 graduated third wrangler in the mathematical tripos. In 1891 he received the first Isaac Newton studentship in astronomy and physical optics at Cambridge, where he studied astronomical spectroscopy with Newall. In 1893 Sampson published “On the Rotation and Mechanical State of the Sun”, in which he discussed the distribution of temperature by radiation and absorption. In the same year he was elected professor of mathematics at the University of Durham and also started his great work on the four large satellites of Jupiter.

The advent of the Harvard photometric eclipse observations of the satellites of Jupiter stimulated Sampson to reexamine previous observations, and as a result he published in 1909 “A Discussion of the Eclipses of Jupiter’s Satellites 1878–1903.” He developed a new theory for the motions of the four satellites and in 1910 published Tables of the Four Great of Jupiter. (Sampson’s tables have since formed the basis for computing the phenomena for the national ephemerides.) The new theory itself was not published until 1921 in “Theory of the Four Great Satellites of Jupiter.”

In 1910 Sampson was appointed astronomer royal for Scotland and professor of astronomy at the University of Edinburgh, where he interested himself in problems concerning the determination of time. He encouraged the development of the Shortt free-pendulum clock, which became standard equipment in many observatories. Sampson also carried out photometric research and introduced the concept of spectrophotometric, gradients. He retired from the observatory in 1937.

BIBLIOGRAPHY

I. Original Works. Sampson’s major works are “On the Rotation and Mechanical State of the Sun,” in Memoirs of the Royal Astronomical Society, 51 (1893), 123–183: “Description of Adam’s Manuscripts on the Perturbation of Uranus,” ibid., 54 (1901), 143–170: “A Discussion of the Eclipses of Jupiter’s Satellites 1878–1903,” in Annals of Harvard College Observatory, 52 (1909), 149–343: “The Old Observations of the Eclipses of Jupiter’s Satellites,” in Memoirs of the Royal Astronomical Society, 59 (1909), 199–256: Tables of the Four Great Satellites of Jupiter (London. 1910): The Sun (Cambridge–New York, 1914): “A Census of the Sky,” in Observatory, 38 (1915), 415–426: and “Theory of the Four Great Satellites of Jupiter,” Memoirs of the Royal Astronomical Society, 63 (1921).

Sampson also edited the unpublished MSS of John C. Adams in Scientific Papers of John Couch Adans, II , pt. 1(Cambridge, 1896–1900).

II. Secondary Literature. On Sampson and his work. see W. M. H. Greaves, “Ralph Allen Sampson,” in Monthly Notice of the Royal Astronomical Society, 100 (1940), 258–263.

Lettie S. Multhauf

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