Joseph Jerôme Lefrançais de Lalande

His parents sent him to Paris to study law; but the accident of lodging in the Hôtel Cluny, where JN 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 NL 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 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 JN Delisle resigned in his favour the chair of astronomy in the College 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 JBJ 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.

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 that science unexampled popularity; his planetary tables, into which he introduced corrections for mutual perturbations, were the bes 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:

• Traite d'astronomie (2 vols., 1764 enlarged. edition, 4 vols., 1771-1781; 3rd ed., 3 vols., 1792)
• Histoir celeste française (1801), giving the places of 50,000 stars
• Bibliographie astronomique (1803), with a history of astronomy from 1780 to 1802
• Astronomie des dames (1785)
• Abrege de navigation (1793)
• Voyage d'un français en Italie (1769), a valuable record of his travel in 1765-1766.

He communicated above one hundred and fifty papers to the Paris Academy of Sciences, edited the Connoissance de temps (1759-1774), and again (1794-1807), and wrote the concludin 2 vols. of the 2nd edition of Montucla's Histoire des mathematique (1802).

See Memoires de I'lnstitut, t. viii. (1807) (JBJ Delambre) Delambre, Hist, de I'astr. au XVIII" siècle, p. 547; Magazin encyclopedique, ii. 288 (1810) (Mme de Salm); JS Bailly, Hist, de I'astr moderne, t. iii. (ed. 1785); J Madler, Geschichte der Himmelskunde ii. 141; R Wolf, Gesch. der Astronomie; JJ Lalande, Bibl. astr p. 428; JC Poggendorff, Biog. Lit. Handworterbuch; M Marie Hist, des sciences, ix. 35.

This entry was originally from the 1911 Encyclopedia Britannica.