During the 17th century mathematicians and scientists increasingly exchanged and communicated their ideas through publications and meetings. This led to the creation of societies and academies, such as the French Académie des Sciences, founded in 1666. Under the secretaryship of Bernard Fontanelle (1657–1757), the Académie paved the way for the scientific ideas of the Enlightenment in France.
Jean Le Rond d’Alembert (1717–1783) was a leading Enlightenment figure. He stated the ratio test for the convergence of an infinite series and tried to formalise the idea of a limit so as to put the calculus on a firm basis. He was the first to obtain the wave equation that describes the motion of a vibrating string. In his later years he wrote most of the mathematical and scientific articles for Denis Diderot’s Encyclopédie, which attempted to classify all the knowledge of the time.
The Académie’s members included Georges-Louis Leclerc, Comte de Buffon (1707–1788), best remembered for his ‘needle experiment’ for estimating experimentally: if we throw N needles of length L randomly onto a grid of parallel lines at distance d apart, then the expected number crossing a line is 2NL/pi d.
[France 1949, 1966, 1959; Wallis and Futuna Islands 1984]