OBITUARY NOTICES OF FELLOWS DECEASED. 



Jean Victor Poncelet, Foreign Member of the Royal Society, was 

 born at Metz on the 1st of July, 1/88. After having studied Mathe- 

 matics for two years at the Lycee Imperial of Metz, he was admitted to 

 the Ecole Poly technique, where he remained till 1810, his studies in 

 the meanwhile having been interrupted by a serious illness. He then 

 entered the Ecole d'Application of Metz as Sublieutenant of Engineers, 

 and left it in March 1812, in order to assist in constructing the defen- 

 sive works of Ramekens in the island of Walcheren. His first engineering 

 work here was the erection of a casemated fort in a very limited time, on 

 a peat soil, without having at his command proper materials for a foundation. 

 In the month of June IS12 he was called away to take part in the Rus- 

 sian campaign, and joined the invading army at Vitepsk. On the 18th of 

 August he reconnoitred Smolensk, exposed to the fire of the garrison, and 

 afterwards took an active share in the battle fought the same day. On the 

 1 9thhe was employed in throwing bridges over the Dnieper below Smolensko, 

 under the fire of the Russian batteries on the opposite bank of the river. 

 Deceiving the enemy by an ostentatious display of preparations for cross- 

 ing at a particular spot, he succeeded in constructing bridges at other 

 points better protected from the Russian fire. During the retreat from 

 Moscow, at Krasnoi, not far from Smolensko, seven thousand French sol- 

 diers under the command of Xey, without artillery, encountered twenty- 

 five thousand Russians with forty-five pieces of artillery, under Prince 

 Miloradowich, on the 18th of November, 1812. In this battle Poncelet 

 charged the Russian batteries at the head of a column of sappers and 

 miners ; his horse was killed under him, and he was taken prisoner. After 

 a painful four months' march through snow, half naked and ill fed, in a 

 season when mercury was repeatedly frozen, he arrived at Saratoff on the 

 Volga. In April 1813, on recovering from an illness brought on by the 

 hardships he had endured, he resolved to occupy his unwelcome leisure 

 with the study of descriptive geometry. But his recollections of the 

 teaching of Monge, Carnot, and Brianchon had been totally effaced by the 

 privations and sufferings he had undergone. Without books to aid him he 

 was obliged, with much labour, to construct bit by bit the elementary pro- 

 positions required for the line of research he was desirous of following. The 

 results of his labours at this time were afterwards published in Gergonne's 

 'Annales, 5 from 181 7 to 1821; and the original manuscripts, written at Sara- 

 toff, were published in 1862. On the conclusion of peace in June 1814, he 

 quitted Saratoff for France, where he arrived in September of the same 

 year. From 1815 to 1825, as Captain of Engineers, he superintended the 

 construction of machinery in the arsenal of Metz. From 1825 to 1835 he 

 was Professor of Mechanics ; and while he imparted to the young officers 

 clear ideas of mechanical science, capable of immediate practical applica- 

 tion, he delivered, at the suggestion of Baron Dupin, gratuitous evening 



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