A sophisticated work tracing the arduous mid-18th-century international expedition to the Latin American equator to determine the “figure of the earth.”
The reigning scientific debate of the Enlightenment concerned the shape of the earth—was it round or flat at the poles? France’s Academy of Sciences, founded by Louis XIV’s Minister of Finance Jean-Baptiste Colbert in 1666, had relied on Descartes’ theory of vortices and believed strongly that the earth was elongated at the poles. On the other hand, Isaac Newton postulated daringly that due to the force of gravity, the earth bulged out at the equator and was flattened at the poles. The two camps needed to prove decisively who was correct. French Minister of the Navy Maurepas was anxious to know if Newton was correct, as the shape of the earth could affect navigation, so he organized a geodesic mission to the equator in order to measure the length of latitude to determine it. The mission to equatorial Peru included French mathematician Pierre Bouguer, chemist Charles-Marie de la Condamine and astronomer Louis Godin. The Geodesic Mission to the Equator invited several Spanish scientists as well and set out in 1735 on what was deemed a three- or four-year mission. It actually lasted nearly 10, involving unbelievable delays, money squandered disgracefully by their leader Godin, long periods of separation, native hostility, war with Spain, a rival expedition to the Arctic Circle and innumerable hardships. In the end, the mission was remarkably accurate, proving the earth was oblate and that Newton was right, and influencing subsequent expeditions by Alexander von Humboldt, Darwin and others.
Ferreiro’s fascinating, absorbing journey involves some complicated explanations, and he lays them out patiently for general readers.