Chappe D’auteroche, Jean-Baptiste

(b. Mauriac, Cantal, France, 23 March 1728; d. San José del Cabo, Cape Lucas, Baja California, 1 August 1769),

astronomy.

An outstanding record at the Collège Louis-le-Grand in Paris brought Chappe to the attention of Jacques Cassini at the Paris observatory. Under the lalter’s direction he published one of the newly augmented editions of Halley’s astronomical tables that had begun to appear in the 1750’s.¹

Chappe’s fame rests essentially on his role in the observation of the transits of Venus of 1761 and 1769, but his first important scientific communication was connected with the antecedent though not unrelated transit of Mercury of 1753.² Between this event and his election to the Académie des Sciences as adjoin tastronomer in 1759, Chappe undertook surveys in Lorraine that involved latitude determinations derived from measurement of the meridian altitudes of selected stars or the sun’s limb, and longitude determinations from lunar eclipses and the occultations of stars.³ Following his appointment to the Academy, he joined the Paris observatory staff, rapidly acquiring a reputation as a skilled observer in close association with J. D. Maraldi, Cassini de Thury, and Lalande.

The twin transits of Venus were the capstone of eighteenth-century observational activity, and Chappe shared in these great events, in the former through his participation in a Siberian winter expedition in 1761 and in the latter through his participation in an expedition to southern California to observe the transit of Venus in 1769. The voyage to Siberia led to studies beyond astronomy and controversies with Empress Catherine II and her spokesmen over the ecological and biological determinants in Russian life and character. Ancillary activity in science was part of the California expedition too, although beyond some minor oceanographic studies (partly inspired by Lavoisier) and an associated natural history of the region around Mexico City, little resulted from Chappe’s final effort. However, his astronomical observations entered into the calculations that J. D. Cassini⁴ employed in 1772 to arrive at a solar parallax of 8.5″.

Between the years of the two transits, Chappe was also involved in the sea tests of Ferdinand Berthoud’s chronometer. Chappe’s report on this never appeared in either the Histoire or Mémoires of the Academy, but was appended afterwards to Berthoud’s own work.⁵ Observations of the meridian transit of Mercury in 1764, of the eclipses of the satellites of Jupiter in 1760–1764, of the solar eclipses of 1765 and 1766 and the lunar eclipse of 1768, and of the comet of 1766 also occupied Chappe’s time between the two great voyages that are the high points of his career. A middling miscellany of other activities in science also marks his achievements, but these are best gleaned from his own works or from the secondary studies listed below.

He died of an unknown epidemic disease that killed all but one of the group sent to California.

NOTES

1. Tables astronomiques de M Halley (Paris, 1752; 2nd ed., Paris, 1754), consisting of the portion of Halley’s tables dealing with the sun and moon with full, explanatory notes by Chappe. The French ed. of the tables dealing with comets and planets came out in 1759, ed. by Lalande.

2. Chappe observed the event from the inner terrace of the Paris observatory. See Procès verbaux de l’Académie royale des sciences (1753), fols. 173–179.

3. These constituted his first contributions to the Mémoires de l’Académie royale des sciences. See Mémoires (1760), pp. 158 ff.

4. Histoire de l’Académic royale des sciences (1769), p. 172.

5. F. Berthoud Traité des horloges marines (Paris, 1773), pp. 539 ff.

BIBLIOGRAPHY

I. Original Works. Further observations are in “Addition au mémoire précédent, sur les remarques qui ont rapport à l’anneau lumineux, et sur le diamétre de Vé nus, observé à Tobolsk le 6 Juin 1761.” in Mémoires l’Aca-démie royale des sciences (1761), 373–377. His travels to Siberia and California are covered in “Extrait du voyage fait en Sibérie, pour l’observation de Vénus sur le disque du Soleil, faite à Tobolsk le 6 Juin 1761,” ibid., 337– 372, freely trans. as “Extract from a Journey to Siberia, for Observing the Transit of Venus over the Sun,” in Gentleman’s Magazine, 33 (Nov. 1763). 547–552; “The Same Transit al Tobolsk in Siberia.” in Philosophical Transactions of the Royal Society, 70 (1761), 254 ff.; Mémoire du passage de Vénus sur le Soleil; contenant aussi quelques autres observations sur l’astronomie, et la déclinaison de la boussole faites à Tobolsk en Sibérie l’année 1761 (St. Petersburg, 1762); Voyage en Californie pour l’observation du passage de Vé nussur le disque du Soleil, le 3 Juin 1769; contenant les observations de ce phénomène. et la description historique de la route de l’auteur à travers le Mexique (Paris, 1772); A Journey into Siberia Made by Order of the King of France (London, 1774); Voyage en Sibérie, fait par ordre du Roi en 1761; contenant les moeurs, les usages des Russes, et l’é talactuel de cette puissance: la description géographique et le nivellement de la route de Paris à Tobolsk (Paris, 1778); and A Voyage to California to Observe the Transit of Venus (London, 1778).

II. Secondary Literature. On Chappe d’Auteroche or his work, see Angus Armitage. “Chappe d’Auteroche: A Pathfinder for Astronomy,” in Annals of Science, 10 (1954), 277–293: J. P. G. de Fouchy, “Éloge de M. l’Abbé Chappe,” in Histoire de l’Académie royale des sciences (1769), 163–172: “Éloge de M. l’Abbé Chappe,” in Né cro-loge des hommes célèbres de France par line société de gens de lettres (Paris, 1771), VI, 133–157: and Harry Woolf, The Transits of Venus. A Study of Eighteenth-Century Science (Princeton, 1959).

Harry Woolf