A French mathematician and philosopher, born near St. Quentin; contributed to the "Encyclopédie"; was of the Encyclopedist school; took sides with the Revolutionary party in the interest of progress; voted with the Girondists usually; suspected by the extreme party; was not safe even under concealment; "skulked round Paris in thickets and stone-quarries; entered a tavern one bleared May morning, ragged, rough-bearded, hunger-stricken, and asked for breakfast; having a Latin Horace about him was suspected and haled to prison, breakfast unfinished; fainted by the way with exhaustion; was flung into a damp cell, and found next morning lying dead on the floor"; his works are voluminous, and the best known is his "Exquisse du Progrès de l'Esprit Humain"; he was not an original thinker, but a clear expositor (1743-1794).