(b. Paris, France, 28 February 1704; d. Cádiz, Spain, 11 September 1760)
The son of François Godin, a lawyer in the Parlement, and Elisabeth Charron, Louis received his early training at the Collège de Beauvais. Although his courses in humanities were intended as a background for legal studies, he turned thereafter to philosophy and ultimately to astronomy, in which he received instruction under Joseph Delisle at the Collège Royal.
Having entered the Academy of Sciences in 1725, Godin presented his first memoir there the following year. Inspired by an appearance of a meteor which had frightened many people, Godin addressed himself to such transient phenomena, offering, for example, both a history and a physical explanation of displays of northern lights. It was partially the superiority of that historical analysis that led the Academy to involve Godin in its own historical project. For the next few years Godin concerned himself with editing the eleven volumes of the Academy’s Mémoires from 1666 to 1699, the writing of its Histoire for nineteen of those years, and the preparation of a four-volume index of the materials included in this basic collection (Histoire et les Mémoires de l’Académie Royale des Sciences) from 1666 to 1730.
As time-consuming as these activities were, they did not prevent Godin from engaging in astronomical work. In addition to observing some eclipses at the royal observatory, he brought out, in 1727, an appendix to Philippe de La Hire’s astronomical tables, a work which indicated his suitability for assuming, in 1730, the preparation of the Academy’s annual ephemeris, the Connaissance des temps; he continued this task until 1735. Meanwhile, Godin had obtained his own observational site, where he viewed various eclipses of 1731, 1732, and 1733 and duly reported the observations to the Academy. The observation dealing with the lunar eclipse of 1732 was more than a simple report, since it offered a comparison with corresponding observations elsewhere and utilized these data to deduce longitudinal differences between observation sites. Moreover, his concern with the phenomenon in general led him to propose a method for the determination of lunar parallax by means of lunar eclipses.
Of Godin’s other works of this period, about half were devoted to various instrumental and observational problems. These included a memoir and a later addendum on the construction, verification, and placing of a mural quadrant in the plane of the meridian, a description of a commodious observational tower, a means of determining the height of the pole independently of refraction, and a method for observing the variation of the magnetic needle at sea. The other half dealt with various aspects of planetary theory and positional changes of standard reference lines and points. Included here were memoirs concerned with the problem of the place of greatest reduction from the ecliptic to the equator and with a method for determining planetary nodes, with the apparent movements of the planets in epicycles, and with the diminution of the obliquity of the ecliptic and its amount. In none of these works was Godin responsible for any new insight or basic improvement.
Similar judgment would also apply to the one remaining memoir of this period, the 1733 paper on a means for tracing parallels of latitude. But because it contained reflections on the proportions of these circles in differing figures of the earth, this memoir led Godin soon thereafter to propose that the Academy send an expedition to the equator to resolve the issue between the “Cassinians” and the “Newtonians” with their respective views of the earth’s prolateness or oblateness. Having accepted this plan, the Academy logically named Godin to undertake this task, along with Pierre Bouguer and Charles de La Condamine. He went first to England to consult with Edmond Halley and other astronomers; there he was received into the Royal Society and furnished with several instruments. As it turned out, however, Godin contributed little to the expedition.
Despite great and various difficulties, the members of the expedition did ultimately measure an arc of about three degrees in Ecuador, a province of the Spanish viceroyalty of Peru. Two slightly different figures for the length of a degree were arrived at by Bouguer and La Condamine, each of whom published an account of the voyage after returning to Paris. On the basis of his separate effort undertaken with Jorge Juan and Antonio de Ulloa, the two Spanish naval officers whose collaboration was one of the costs of Spain’s cooperation, Godin produced still another figure. Because the later-dispatched but earlier completed expedition to Lapland had already resolved the basic issue in favor of oblateness, these equatorial figures immediately served only as verifications, although subsequently they were employed in the calculations establishing the metric system.
Godin never published his account of the voyage, despite subsequent claims that he was working on it, but he did accomplish other works during this period. La Condamine related Godin’s 1737 experiments on the speed of sound, and Godin himself reported to the Academy on the length of the seconds pendulum observed at Santo Domingo on the way to Ecuador and on a lunar eclipse viewed in Quito in 1737. Finally, in 1738, he submitted a memoir on a method for determination of solar parallax.
Bouguer and La Condamine left Peru in 1743; Godin stayed on, as professor of mathematics at the University of San Marcos, until 1751. After a year in Paris, during which he fruitlessly sought the return of his academic place and pension, he went to Spain and became the director of the Academy of Naval Guards at Cádiz. Although he returned to Paris briefly in 1756, reentering the Academy in “veteran” status and participating in a base-line verification, the preparation of a mathematics course for his Cádiz students was the principal occupation of his last years. Like his expedition account, a planned astronomical bibliography and a collection of astronomical observations remained unrealized.
Godin’s 1728 marriage to Rose-Angélique le Moyne produced a son and a daughter, both of whom predeceased him. Godin died in 1760, following an attack of apoplexy.
I. Original Works. Godin’s only publication independent of Academy sponsorship was his Appendice aux tables astronomiques de Lahire (Paris, 1727). Under the aegis of the Academy, he constructed five vols. of the Connaissance des temps, drew up and published the fourvolume Table alphabétique des matières continues dans l’Histoire et les Mémoires de l’Académie royale des sciences ... (Paris, 1734), in the preparation of which collection he participated and presented many papers. His first contribution was “Sur le météore qui a paru le 19 octobre 1726,” in the Mémoires for 1726, 287–302. His reports of eclipses may be seen in the Mémoires as follows: lunar (1729), 9–11, 346–349; (1731), 231–236: (1732), 484–494; (1733), 195–197; (1739), 389–392; solar (1726), 330–331; (1733), 149–150. His suggestions for lunar and solar parallax determinations appeared in the Mémoires as “Sur la parallaxe de la lune” (1732), 51–63; and “Méthode de déterminer la parallaxe du soleil par observation immédiate” (1738), 347–360.
Godin’s pendulum observation, “La longueur du pendule simple, qui bat les secondes du temps moyen, observée à Paris et en petit Goave en l’ile Saint-Domingue,” was in Mémoires (1735), 505–521. Most of his other instrumental and observational offerings were also in the Mémoires: “Du quart de cercle astronomique fixe” (1731), 194–222; “Addition qu’il faut faire aux quarts-decercle fixes dans le méridien” (1733), 36–39; “Méthode nouvelle de trouver la hauteur de pôle” (1734), 409–416; “Méthode d’observer la variation de l’aiguille aimantée enmer” (1734), 590–593; his tower description, however, appeared in M. Gallon, ed., Machines et inventions approuvées par l’Académie royale des sciences depuis son établissement jusqu’ à présent, avec leurs descriptions, 7 vols. (Paris, 1735–1777), VI, 49–52.
Godin’s remaining contributions to the Mémoires were “Solution fort simple d’un problème astronomique d’oú l’on tire une méthode nouvelle de déterminer les noeuds des planétes” (1730), 26–33; “Des apparences du mouvement des planétes dans un épicycle” (1733), 285–293; “Méthode pratique de tracer sur terre un paralléle par un degré de latilude donnée; et du rapport du même parallèle dans le sphéroïde oblong et dans le sphéroïde aplati” (1733), 223–232; and “Que l’obliquité de l’écliptique diminue, et de quelle manière; et que les noeuds des planètes sont immobiles” (1734), 491–502.
II. Secondary Literature. The “official” éloge for the Academy was written by Grandjean de Fouchy, another Delisle student and Godin’s friend, and appeared in the Histoire de l’Académie...(1760), 181–194. Although mentioning, and lauditorily analyzing, many of his memoirs and other works, this éloge does not provide explicit citations; better for the latter, although weak on analysis, are several subsequent biographical treatments: J. M. Quérard, La France littéraire ou Dictionnaire bibliographique des savants..., 10 vols. (Paris, 1827–1839), III, 391; J. F. Michaud, ed., Biographie universelle, 45 vols. (Paris, 1843–1858), XVII, 23; and Niels Nielsen, Géomètres français du dis-huitième siècle (Paris, 1935). pp. 192–195. The best general account of his astronomical work, with fair bibliographical information, is J. B. J. Delambre, Histoire de l’astronomie au dix-huitième siècle (Paris, 1827). pp. 331–136; he also provides a separate treatment of Godin’s arc-measurement venture in G. Bigourdan, ed., Grandeur et figure de la terre (Paris, 1912), pp. 85–145.
Recent treatments of the problem of the shape of the earth are the brief but general account of Seymour L. Chapin, “The Size and Shape of the World,” in UCLA Library Occasional Papers, no. 6 (1957), 1–7; and the large-scale account of the mid-1730’s expeditions by Tom B. Jones, The Figure of the Earth (Lawrence, Kans., 1967), esp. ch. 6.
On Godin’s observational site, see G. Bigourdan, Histoire de l’astronomie d’observation et des observatoires en France, II (Paris, 1930), 42–47.
Seymour L. Chapin