The question of the ``Centre of oscillation'' from 1660 until 1690 (Q2717924)

The early history of the study of the compound pendulum over the century 1643-1743 can be divided into three periods: (1) the work of Torricelli, Mersenne and Roberval prior to the publication of \textit{Horologium} of C. Huygens; (2) the theories of Huygens, Wren, Catalan, Mariotte, de l'Hôspital and Jacob Bernoulli; (3) later developments up to the investigations of d'Alembert. The author finds that the middle period, which involved disputes over the principles underlying possible theories, has not been studied in sufficient detail and sets out to remedy this here. The purpose of the paper is ``to shed light on, what must be at that time, a good principle for mechanics'' and ``to provide an insight on what became methodologically important for new mechanics''.