The Satellites of Mars: Prediction and Discovery

Swift Jonathan , Gulliver's travels (London, 1726), part 3, ch. 3.

See Nicolson Marjorie H. and Mohler Nora M. , “The scientific background of Swift's Voyage to Laputa” reprinted in Nicolson's Science and imagination (Cornell, 1956); Boyd's Lyle “The provenance of Swift” in The graduate journal, vii (1965), 235–43, provides the whimsical explanation that Swift was a Martian transported to earth.

Gould S. H. , “Gulliver and the moons of Mars”, Journal of the history of ideas, vi (1945), 91–101.

de Morgan Augustus , in A budget of paradoxes (London, 1872), 133–4, proposes that John Arbuthnot advised Swift on the mathematics.

Voltaire , Micromegas (1752), ch. 3. Father Louis-Bertrand Castel (1688–1757) was a prolific and determined critic of the new Newtonian science, who looked back to Descartes and Kircher for inspiration (see Schier Donald S. , Louis Bertrand Castel, Anti-Newtonian scientist (Cedar Rapids, Iowa, 1941)). A rapid examination of Castel's principal work, Traité de physique sur la pesanteur universelle des corps (1724) has failed to locate the argument cited by Voltaire, although I have found a series of curious propositions based on a theory of vortices, such as “109—if the moon is destroyed, it is possible that Mars would take its place; it is possible that Venus and the earth would change places; it is possible that the earth would be overpowered by Venus, or Mars, or Mercury and become its satellites”. Perhaps an explicit denial of the existence of Martian satellites is found in one of his 50 articles on the theory of vortices written between 1724 and his death.

le Bovier de Fontenelle Bernard , Entretiens sur la pluralité des mondes (1866); the quotation here is from p. 211 of an anonymous translation published in London in 1767, but an English translation by Glanvill was already available in 1702.

Quoted by Hall Asaph in Observations and orbits of the satellites of Mars (Washington, 1878) from Brewster's David “Life of Galileo”, pp. 33–4 in Martyrs of science (London, 1874). Actually the quotation is from Kepler's Dissertatio cum nuncio sidereo—see pp. 14 and 77 of Rosen's Edward Kepler's Conversation with Galileo's Sidereal messenger (New York, 1965).

Kepler J. , Narratio de observatis quatuor Jouis satellitibus (Frankfurt, 1611), p. 3v; Johannes Kepler Gesammelte Werke, iv (Munich, 1941), 319.

Carlos Stafford Edward , The sidereal messenger, and a part of the Preface to Kepler's Dioptrics (London, 1880), 88.

The original letter is unknown except for its publication in Kepler's Dioptrice (Augsburg, 1611), 15–16; see Hammer's F. note in Johannes Kepler Gesammelte Werke , iv (Munich, 1941), 515.

The order of the observations is given explicitly here because of the light it sheds on a statement written by Todd about 30 years later for the Cosmopolitan magazine of 11 March 1908, p. 343: “So mine was the first eye that ever saw Phobos recognizing it as a satellite.”

Hall Asaph , op. cit. (n. 7); d'Arrest H. , Astronomische Nachrichten, lxiv (1865), 73–4.

Newcomb Simon , The reminiscences of an astronomer (Boston, 1903), 192.

I am indebted to the Hall family for allowing me to quote a portion of this letter; it is currently in the possession of Nancy Hall Denio. Asaph Hall further described his observing method in an unindexed letter in Monthly notices of the Royal Astronomical Society, xxxviii (1877), 205–8: “I began to examine the region close to the planet, and within the glare of light that surrounded it. This was done by keeping the planet just outside the field of view, and turning the eye-piece so as to pass completely around the planet.”

Holden to Rogers Admiral John Rear , Superintendent of the Naval Observatory, Ferry Dobbs , New York, 28 August 1877; the letter is presumably at the U.S. Naval Observatory.

Hall to Searle Arthur , Washington, 9 October 1877, in the Harvard University Archives; Hall's greatest potential competition was from the great 48-inch Melbourne reflector, especially since Mars was better placed for southern observers.

Nature, xvi (1877), 456–7.

Newcomb Simon , op.cit. (n. 13), 141–2.

Hall to Professor Newcomb, South Norfolk, Conn., 23 August 1901, in the Simon Newcomb papers in the Library of Congress.

Hall to Pickering E.C. , quoted with permission of the Harvard University Archives.