The New Student's Reference Work/D'Alembert, Jean le Rond

D'Alembert (dä′lon′bêr), Jean le Rond, a distinguished French mathematician and dynamicist, born in 1717, died in 1783. He was the illegitimate son of a French artillery general, Destouches, and of Mme. de Tencin. Left on the steps of a church in Paris, he was sent, not to a foundling asylum, but to a small town near Amiens. His father, returning from foreign lands, rescued the boy, took him to Paris, and educated him at the Mazarin College. It was at this institution that he assumed the name D'Alembert. At the age of 20 he settled to his life-work, the study of geometry and dynamics. He published an enormous number of papers; but his Treatise on Dynamics, which he completed at the age of 26, transcends all his other work in importance. The greatest advance which we owe to him is the introduction of a method (known as D'Alembert's principle) by which any of the complex problems of dynamics may be reduced to a corresponding problem of statics. By this simplification he obtained the solution of many otherwise insoluble problems. D'Alembert's Dynamics has been translated into German in volume 106 of Ostwald's Classics of the Exact Sciences, where it may be had at small cost.