PRONY, GaspardClair François Marie Riche de (1755-1839), a celebrated French engineer, was born at Chamelet, in the department of the Rhone, 2 2d July 1755, and was educated at the École des Ponts et Chaussées. His Mémoire sur la poussée des voûtes published in 1783, in defence of the principles of bridge construction introduced by his master Peronnet, attracted special attention. Under Peronnet he was engaged in restoring the fort of Dunkirk in 1785, and in erecting the bridge of Louis XVI. in 1787. The laborious enterprise of drawing up the famous Tables du Cadastre was entrusted to his direction in 1792, and in 1798 he was appointed director at the École des Ponts et Chaussées. He was employed by Napoleon to superintend the engineering operations both for protecting the province of Ferrara against the inundations of the Po and for draining and improving the Pontine Marshes. After the Restoration he was likewise engaged in regulating the course of the Rhone, and in several other important works. He was made a baron in 1828, and a peer in 1835. He was also a member of the principal academies and scientific societies of Europe. He died at Lyons 31st July 1839.