The academician astronomers travelling in the 18th century

In the 18th century, astronomers of the Academie des sciences of Paris made various contributions to the improvement of navigation: terrestrial determ inants of longitude which improved charts for navigators, testing of marine clocks for longitude determinations at sea. They were also invited to join exploratory voyages; such as d'Agelet, who accompanied Kerguelen and later La Perouse. In order to resolve the Cassini-Newton controversy regarding t he shape of the Earth, the Academie proposed, in 1735, that two expeditions should be ,ade with a view to measuring a meridian arc: one in "Perou" clo se to the equator (Godon, Bouger, La Condamine); the other in Lapland (Maup ertuis, Clairaut). The results concluded that the Earth was flat on the sid es of the poles, as predicted by Newton. By mid-18th century, the first pur ely astronomical expedition (La Caille, Cape of Good Hope) led to the creat ion of an austral celestial map and new parallaxes. Later, Clappe d'Auteroc he, Le Gentil and Pingre travelled to observe two transits of Venus over th e Sun (1761, 1769) for the improvement of the solar parallax. (C) Academie des sciences/Elsevire, Paris.