Jacques, a laborious French mathematician, was of Jewish extraction, and was born at Bouligneux, in the principality of Dombes, in 1640. His passion for mathematics was developed at an early age. On the death of his father, who had designed him for the church, Ozanam abandoned divinity and took to mathematics, at Lyons. His removal to Paris soon afterwards was the means of increasing alike his zeal and his fame. He devoted much of his time to his pupils, both native and foreign; and he wrote many valuable mathematical works. The latter part of the career of Ozanam was clouded with domestic suffering; and the war of the Spanish succession deprived him of many of his pupils. Yet he preserved his cheerful and amiable disposition, until a stroke of apoplexy closed his career on the 3d April 1717.

Among a great number of works on theoretical and practical mathematics, the best known and most esteemed are the Dictionnaire Mathématique, Paris, 1690, 4to; Cours de Mathématiques, ibid., 1693, 5 vols., 8vo; Récérations Mathématiques et Physiques, ibid., 1694, 2 vols., 8vo, improved by Monnecu, Paris, 1778, 4 vols., 8vo, and still further improved in the English edition of Dr Hutton, London, 1803, 8vo. Ozanam left in manuscript a treatise on the Analysis of Diophantus, which was in the library of D'Aguesseau. (See his Eloge by Fontenelle, the Mémoires of Niceron, and the Dictionary of Chauffepié.)