# 1911 Encyclopædia Britannica/Lalande, Joseph Jérôme Lefrançais de

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​LALANDE, JOSEPH JÉRÔME LEFRANÇAIS DE (1732–1807), French astronomer, was born at Bourg (department of Ain), on the 11th of July 1732. His parents sent him to Paris to study law; but the accident of lodging in the Hôtel Cluny, where J. N. Delisle had his observatory, drew him to astronomy, and he became the zealous and favoured pupil of both Delisle and Pierre Lemonnier. He, however, completed his legal studies, and was about to return to Bourg to practise there as an advocate, when Lemonnier obtained permission to send him to Berlin, to make observations on the lunar parallax in concert with those of N. L. Lacaille at the Cape of Good Hope. The successful execution of his task procured for him, before he was twenty-one, admission to the Academy of Berlin, and the post of adjunct astronomer to that of Paris. He now devoted himself to the improvement of the planetary theory, publishing in 1759 a corrected edition of Halley’s tables, with a history of the celebrated comet whose return in that year he had aided Clairault to calculate. In 1762 J. N. Delisle resigned in his favour the chair of astronomy in the Collège de France, the duties of which were discharged by Lalande for forty-six years. His house became an astronomical seminary, and amongst his pupils were J. B. J. Delambre, G. Piazzi, P. Mechain, and his own nephew Michel Lalande. By his publications in connexion with the transit of 1769 he won great and, in a measure, deserved fame. But his love of notoriety and impetuous temper compromised the respect due to his scientific zeal, though these faults were partially balanced by his generosity and benevolence. He died on the 4th of April 1807.
Although his investigations were conducted with diligence rather than genius, the career of Lalande must be regarded as of eminent service to astronomy. As a lecturer and writer he gave to the science unexampled popularity; his planetary tables, into which he introduced corrections for mutual perturbations, were the best available up to the end of the 18th century; and the Lalande prize, instituted by him in 1802 for the chief astronomical performance of each year, still testifies to his enthusiasm for his favourite pursuit. Amongst his voluminous works are Traité d’astronomie (2 vols., 1764; enlarged edition, 4 vols., 1771–1781; 3rd ed., 3 vols., 1792); Histoire céleste française (1801), giving the places of 50,000 stars; Bibliographie astronomique (1803), with a history of astronomy from 1781 to 1802; Astronomie des dames (1785); Abrégé de navigation (1793); Voyage d’un françois en Italie (1769), a valuable record of his travels in 1765–1766. He communicated above one hundred and fifty papers to the Paris Academy of Sciences, edited the Connoissance des temps (1759–1774), and again (1794–1807), and wrote the concluding 2 vols. of the 2nd edition of Montucla’s Histoire des mathématiques (1802).
See Mémoires de l’Institut, t. viii. (1807) (J. B. J. Delambre); Delambre, Hist. de l’astr. au XVIII $^e$ siècle, p. 547; Magazin encyclopédique, ii. 288 (1810) (Mme de Salm); J. S. Bailly, Hist. de l’astr. moderne, t. iii. (ed. 1785); J. Mädler, Geschichte der Himmelskunde, ii. 141; R. Wolf, Gesch. der Astronomie; J. J. Lalande, Bibl. astr. p. 428; J. C. Poggendorff, Biog. Lit. Handwörterbuch; M. Marie, Hist. des sciences, ix. 35.