By Larrie D. Ferreiro. Basic Books. 350 pages, $28
Ship navigation in earlier centuries was by star sightings and luck. Better information on the shape and size of the Earth was critical for commerce and battle plans. French philosopher Rene Descartes argued that the Earth was elongated at the poles like an egg. British philosopher Isaac Newton suggested it had a bulge in the equator and flattened at the poles.
In 1734, the French, in cooperation with Spain, funded a scientific expedition called the Geodesic Mission. Eighteen scientists were to go to South America and, at the equator, measure the distance between one angle of the latitude. The author describes the incredible adversities encountered by the team: the jungles and highlands of equatorial Peru, attacks by local inhabitants, near-mutiny, war, siege and other trials.
In following the work in their project, it is most impressive to see the intellectual skills people possessed by that generation, particularly in mathematics and astronomy.
When the project was over, the author describes the return journey of each individual team member. Some took a direct route back to France, while others lingered for years before returning. One went by a tributary of the Amazon to a port on the Pacific.
The last section of the book is most interesting — describing the impact of this one scientific expedition on future expeditions in determining the size and shape of the Earth, with the goal of improving navigation.
Larrie Ferreiro spent years researching all over the world for information for this book. His fine writing skills give a very accurate technical and historical account of the Geodesic Mission.
Which was right: Descartes’ theory that the Earth was elongated or Newton’s theory that the Earth had a bulge at the equator? Sorry, you will have to read the book to find out.
– William Mashburn Sr. is professor emeritus of mechanical engineering at Virginia Tech and is executive director of the Institute of Energy Professionals.