Jean le Rond d' Alembert

Alembert, Jean le Rond d' (1717–83), French philosopher, physicist, and mathematician, a leading figure in the French Enlightenment, and coeditor with Denis Diderot of the Encyclopedie. His early fame rested on his formulation of d'Alembert's principle in mechanics (1743). His other works treat calculus, music, philosophy, and astronomy.