1911 Encyclopædia Britannica/Poncelet, Jean Victor

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PONCELET, JEAN VICTOR (1788–1867), French mathematician and engineer, was born at Metz on the 1st of July 1788. From 1808 to 1810 he attended the École polytechnique, and afterwards, till 1812, the École d'application at Metz. He then became lieutenant of engineers, and took part in the Russian campaign, during which he was taken prisoner and was confined at Saratov on the Volga. It was during his imprisonment here that, “ privé de toute espèce de livres et de secours, surtout distrait par les malheurs de ma patrie et les miens propres,” as he himself puts it, he began his researches on projective geometry which led to his great treatise on that subject. This work, the Traité des propriétés projectives des figures, which was published in 1822 (2d ed., 2 vols. 1865–1866), is occupied with the investigation of the projective properties of figures (see Geometry). This work entitles Poncelet to rank as one of the greatest of those who took part in the development of the modern geometry of which G. Monge was the founder. From 1815 to 1825 he was occupied with military engineering at Metz; and from 1825 to 1835 he was professor of mechanics at the École d'application there. In 1826, in his Mémoire sur les roues hydrauliques à aubes courbes, he brought forward improvements in the construction of water-wheels, which more than doubled their efficiency. In 1834 he became a member of the Académie; from 1838 to 1848 he was professor to the faculty of sciences at Paris, and from 1848 to 1850 commandant of the École polytechnique. At the London International Exhibition of 1851 he had charge of the department of machinery, and wrote a report on the machinery and tools on view at that exhibition. He died at Paris on the 23rd of December 1867.

See J. Bertrand, Éloge historique de Poncelet (Paris, 1875).