James, a laborious mathematician, was born in the year 1640, at Bouligneux, in the principality of Dombes. His family was of Hebrew extraction, but had long been converts to the Catholic faith; and some of them had held considerable places in the parliament of Provence. Nature had given him a decided taste for the exact sciences; but his father, who intended him for the church, took care not to foster an inclination adverse to his views; and, during four years, young Ozanam studied divinity, though with little pleasure or success. As he advanced in years, his aversion to this study increased in the same proportion as his ardour for the sciences, to which he was denied access, became more and more intense. His father, however, died just as he was about to complete his course of theology; and being now his own master, he renounced all idea of entering the church, and, devoting himself entirely to the mathematics, made so great progress that, at the age of fifteen, he composed a work in which he afterwards found some things deserving of publication. As, by the custom of Bresse, the estate went to the eldest son, the subject of this notice had no other resource than to teach mathematics, which he had not been permitted to study; and, accordingly, having established himself at Lyons, he there supported himself for some time by the produce of his lessons, supplying the deficiency by his gains at play. Some foreigners, pupils of his, to whom he had lent fifty pistoles without taking any note or obligation for repayment, having mentioned the circumstance to the father of Chancellor d'Aguesseau, that magistrate, touched with so generous a trait of character, invited Ozanam to come to Paris, where he would necessarily find greater facilities for teaching than at Lyons. Ozanam accepted this proposition the more readily, because he desired above all things to make the acquaintance of the great geometers whose works he had studied; and having abandoned play in order to devote himself entirely to the mathematics, he had soon a great number of pupils. But at first he wanted the prudence necessary to profit by his success. He was young, handsome, and sprightly, and being addicted to gallantry, he became entangled in some intrigues which, besides the annoyance they gave him, exposed him to considerable ridicule. Reflection followed, and celibacy appearing to him a dangerous state, he married a young woman almost without fortune, who had interested him by an air of gentleness, modesty, and virtue. Nor, adds Fontenelle, did these fair appearances deceive him. Satisfied with his condition, he divided his time bet- between study and teaching. He gave lessons during peace; and the time of war he employed in composing works which added to his ease and comfort as well as to his reputation. He had as many as twelve children, who nearly all died at an early age, and whom he regretted, says his panegyrist, "comme s'il eût été riche, ou plutôt comme ne l'étant point; car ce sont les plus riches qui se tiennent les plus incommodes d'une nombreuse famille." He lost his wife in 1701, and with her all the comfort and happiness of his life. Neither did this misfortune come single. The war of the succession, by depriving him of his scholars, reduced him to a melancholy condition. But his patience was never for an instant ruffled, and notwithstanding the difficulties in which he found himself involved, he lost nothing of his gaiety. About this time he was admitted into the Academy of Sciences as an élève, a title which it was intended to elevate in general estimation by bestowing it on a man of Ozanam's age and merit. He appears to have had a prescience of approaching death, arising perhaps from some latent disorder within; and under this impression he refused to receive some foreign noblemen who wished to become his pupils, alleging that he should not live long enough to carry them through a regular course. At length, on the 3d of April 1717, immediately after dinner, which he had eaten with some relish, he felt himself unwell, and asked to be put to bed; but a few minutes afterwards he was struck with an apoplexy, which in less than two hours carried him off. Ozanam was a man of a mild and calm disposition, of a cheerful and pleasant temper, and endeared by a generosity almost unparalleled. After marriage his manners were irreproachable. He was sincerely pious, although in matters of religion he did not allow himself to know more than the people, and studiously avoided intermeddling in theological disputes. He used to say that it was the business of the doctors of the Sorbonne to dispute, of the pope to decide, and of a mathematician to go to paradise in a perpendicular line. He composed with extreme facility, and never made any erasure or correction on his manuscripts, his first copy being always the last.

Besides editions of the Éléments d'Euclide of Père de Challes, of the Géométrie Pratique, and the Traité du Sphère de Boulanger, and some Mémoires in the Collection of the Academy, the Journal des Savants, and other publications, Ozanam wrote, 1. Tables des Sinus, Tangentes, et Secantes, et des Logarithmes, Lyon, 1670, and Paris, 1685, in 8vo; 2. Traité de Gnomonique, Paris, 1673, in 12mo; 3. La Géométrie Pratique, ibid. 1684, in 12mo; 4. Traité des Lignes de premier genre, de la construction des Equations, etc., ibid. 1687, in 8vo; 5. L'Usage du Compas de Proportion expliqué, ibid. 1688, in 8vo; 6. Dictionnaire Mathématique, ibid. 1690, in 4to; 7. Cours de Mathématiques, ibid. 1693, in five vols. 8vo, reprinted at Amsterdam in 1799; 8. Traité de la Fortification, containing the ancient and modern method for the construction and defence of strong places; 9. Recréations Mathématiques et Physiques, ibid. 1694, in two vols. 8vo; 10. Nouvelle Trigonométrie, 1699, in 12mo; 11. Méthode facile pour arpentier ou mesurer toutes sortes de Superficies, ibid. 1699, in 12mo; 12. Nouveaux Éléments d'Algèbre, Amsterdam, 1702, in 8vo; 13. La Perspective Théorique et Pratique, ibid. 1711, in 8vo; 14. La Géographie et Cosmographie, qui traite de la Sphère, ibid. 1711, in 8vo. Ozanam left in manuscript a treatise on the Analysis of Diophantus, which was in the library of D'Aguessacu. (See his Eloge by Fontenelle, the Mémoires de Niceron, and the Dictionary of Chaufepié.)