Jean Picard, a priest, an astronomer and a geodesist, aged 49, has measured an arc of meridian between Paris and Amiens, hence the radius and the circumference of the earth by extrapolation. He is a pupil of Astronomer Pierre Gassendi (†1655), who was also a priest and a philosopher, and as of 1623 a promoter of heliocentricism, ten years before the sentence against Galileo Galilei (†1642). Picard is also one of the 21 first members of the Académie Royale des Sciences  founde

René Descartes ‘Les siècles n’ont rien produit de tel… Ce qui a surtout recommandé sa philosophie, c’est… qu’il a osé substituer des causes qu’on peut comprendre de tout ce qu’il y a dans la nature.’ Christiaan Huygens, natural philosopher, 31 years old, expressing scholars’ debt to René Descartes (†1650), figurehead of Rationalism Twelve outstanding natural philosophers , as we call the ones who study nature, a team of men bound by scholarly debates for years, held a landma