ABSTRACT
This chapter aims to discuss the differences between the two editions of Jean d'Alembert's Traite de Dynamique as regards the controversy over living force. In his preface to the 1743 edition of the Traite de Dynamique, d'Alembert stated that he would consider the motion of a body only as the traversal of a certain space for which it uses a certain time. The two parties, d'Alembert added in 1758, are entirely in accord over the fundamental principles of equilibrium and motion, and their solutions are in perfect agreement. Although the 1758 edition of the Traite did point out that momentum could be considered as a force acting during a given time, and vis viva as a force acting over the space traversed, d'Alembert likewise was anticipated in this insight by Roger Boscovich. Pierre Costabel has shown that Boscovich's De Viribus Vivis suggested a separate graphical representation for each of the two measures of force.
