Belidor, Bernard Forest De

, a member of the academies of sciences of Paris and Berlin, was born in Catalonia in 1697. Being left an orphan at the age of five years, he was educated by an engineer, a friend of his father’s family, and very early discovered a genius for mathematics. In the course of time he was appointed royal professor of the schools of artillery of la Fere, and superintended the education of some scholars who proved worthy of him. His success in this situation procured him also the place of provincial commissary of artillery, but here' his zeal cost him both places. Having discovered by some experiments that a smaller quantity of powder was sufficient to load a cannon than commonly employed: that, for example, eight pounds of powder would produce the same effect as twelve, which was the usual quantity, he thought to pay court to the cardinal de Fleury, then prime minister, by communicating to him in private a scheme by which government might make so important a saving. The cardinal, who was partial to all schemes of economy, listened with pleasure to this of Belidor, and spoke of it to the prince de Dombes, who was master of the ordnance. The prince was astonished that a mathematician, who served under him, and on whom he had conferred favours, should not have communicated this to him, and irritated by what he considered as a mark of disrespect, dismissed him from the posts he held, and obliged him to leave la Fere. t De Valliere, lieutenant-general of artillery, took upon him on this occasion to justify the prince’s conduct, in a printed memorial, and endeavoured at the same time to refute | Belidor’s opinion and experiments, with what success we are not told. Belidor, however, originally born without fortune, was now stripped of the little he had acquired by his talents, and might probably have remained in poverty, had not the prince of Conti, who knew his merit, taken him with him to Italy, and bestowed on him the cross of St. Lewis, an honour which procured him some notice at court. The marshal Bellisle engaged him in his service, and when war-minister, appointed him to the office of inspector of artillery, and gave him apartments in the arsenal at Paris, where he died in 1761. During his laborious and checquered life, he found leisure to write, 1. “Sommaire d‘un cours d’architecture rnilitaire, civil et hydraulique,” 1720, 12 mo. 2. “Nouveau cours de Mathematique, a T usage de I’Artilierie et du Genie,” 4 to, Paris, 1725, a work previously examined by a committee of the academy of sciences, and approved and recommended by them. 3. “La Science des ingenieurs,”. 1729, 4to. 4. “Le Bombardier Francoise,” 1731, 4to. 5. “Architecture Hydraulique,” 1735 1737, 4 vols. 4to. 6. “Dictionnaire portatif de l’ingenieur,” 1738, 8vo. S. “Traite des Fortifications,” 2 vols. 4to. 9. “La science des Ingenieurs dans la concluite des travaux des Fortifications,” 1749, 4to. His biographer says that the most of these works are useful, but that Belidor was not a mathematician of the first order. ¹