Measure of the Earth: The Enlightenment Expedition That Reshaped Our World by Larrie D. Ferreiro (review)

The subject of Measure of the Earth is the first geodesic expedition to the equator to measure a three-degree arc of the meridian by a team of French academicians, Spanish naval officers and their assistants in the first half of the eighteenth century (1735 to 1744). Their journey to the Spanish province of Quito (Ecuador) was, Ferreiro writes, “one of the most famous and widely published tales of science, travel and adventure during the eighteenth and nineteenth centuries” (p. 259). Ferreiro’s aim is to recover some of the former glory and intrigue associated with this expedition—and to tell a good story in the process. He has woven together a tale, intended for a popular audience, about how a series of debates about the earth’s shape, combined with a bit of luck, imperial ambition, and persistence resulted in an unforgettable adventure to determine, once and for all, the real shape of the earth.

Measure of the Earth introduces readers to many of the challenges and intrigue that French academicians and Spanish officers faced when they arrived in South America. The book also makes the scientific debates that gave way to the expedition accessible to nonexperts. In short, members of the Paris Academy of Science, many of whom were followers of René Descartes, believed that the earth was spherical and elongated (like an egg) at the poles; they adamantly opposed the mainly British followers of Isaac Newton, who argued that the earth was actually flattened at the poles. With the collapse of the Anglo-French alliance in 1731, the intellectual rift that had emerged between French and British scientists became increasingly politicized. Resolving the question of the earth’s exact size became a matter of national pride as much as those who justified the expedition insisted upon the practical reasons to undertake it. In order to put an end to the debate, French academicians knew they needed to take a series of latitudinal measurements at the equator. The problem was, they had no access to territories in equatorial regions; however, all this changed when France signed the Treaty of El Escorial with Spain in late November 1733 and the Spanish agreed to allow a jointly led geodesic mission to their equatorial kingdom.

Ferreiro attributes the eventual success of the expedition mainly to the power of its leaders’ efforts and personalities, especially Jean Baptiste Godin, Charles-Marie de la Condamine, Pierre Bougher, Jorge Juan, and Antonio de Ulloa. He describes La Condamine, for example, as “intrepid and daring,” “scientifically curious and a keen observer,” someone with a “cool head and good judgment” (p. 39). Yet, after reading historian of science Neil Safier’s recent treatment of this same expedition in his book, Measuring the New World: Enlightenment Science and South America (2008), one cannot help but question this portrayal of La Condamine and the other Europeans involved in the expedition. As Safier shows, after he returned from South America, La Condamine worked hard to portray himself as a hero and a scientific authority, one who had been ideally suited for this particular enterprise—and the key to its success. In other words, the very same texts that Ferreiro has read in order to affirm the power of La Condamine’s personality and heroism were texts that La Condamine helped produce when he returned to Europe in order to ensure that he was remembered in precisely this way.

Safier’s book also unsettles the binary opposition Ferreiro accepts between European scientists and the “Indian workers whose names,” Ferreiro writes, “have been lost to history” (p. 156). The assumption here is that La Condamine, Bougher, and other team members created scientific knowledge through instruments and practices that were separated from and inaccessible to the Indian workers who helped them—and that European team members were mostly indifferent to local knowledge(s). “The supposedly careful European scientists,” Ferreiro notes, “seemed almost determined to take...