Delambre, JEAN JOSEPH

Delambre, JEAN JOSEPH, astronomer, born at Amiens, 29th September 1749, taught, and studied physics and astronomy under Lalande. The discovery of Uranus by Herschel in 1781 gave him the first opportunity of attracting the attention of the learned world in general by preparing tables of the motion of the new planet. Soon after, he commenced the construction of new solar tables, and tables of the motions of Jupiter and Saturn. Along with Méchain, he was appointed by the French government, in 1792, to measure the arc of the meridian between Dunkirk and Barcelona, which was completed in 1799 (see MÉTRE, ARAGO). He was elected member of the Academy, and in 1803 perpetual secretary of the mathematical section of the Institute. The result of his measurements appeared in his great work, Base du Système Métrique Décimal (1806-10). In 1807 he obtained the chair of Astronomy at the Collège de France, rendered vacant by the death of Lalande, his master and friend. In 1814 he was appointed a member of the Council of Public Instruction. He died at Paris, 19th August 1822. Delambre received a multitude of honours during his lifetime. He was a member of most of the learned bodies in Europe, and an officer of the Legion of Honour. His writings are very numerous. The principal are Traité d'Astronomie (1814), Histoire de l'Astronomie Ancienne (1817), Histoire de l'Astronomie du Moyen Âge (1819), Histoire de l'Astronomie Moderne (1821), and Histoire de l'Astronomie au Dix-huitième Siècle (1827). Besides these, Delambre wrote several excellent Mémoires.