The Man Who Flattened the Earth: Maupertuis and the Sciences in the Enlightenment

  • Mary Terrall
University of Chicago Press: 2002. 408 pp. $39, £27.50

Being Pierre-Louis Moreau de Maupertuis was hard work. Some of that work was deciding what kind of man of science he wanted to be. Starting out in mathematics and mechanics, he eventually made notable contributions to the study of heredity, and ended his career swept up in a series of metaphysical disputes. Some of the hard work was physical: his most notable scientific research in geodesy called for courage and a willingness to suffer for science. In 1736, he led an expedition to Lapland to establish the precise measure of a degree of latitude. Heavy astronomical instruments had to be lugged up mountains at the northern end of the Gulf of Bothnia, and measuring rods were laid end-to-end for miles over frozen rivers. In winter the cold was so cruel that the intrepid group's cups of eau-de-vie froze to their lips, and when summer came, swarms of mosquitoes drove them to the brink of madness.

The expedition to Lapland was a display of manly fortitude as much as an exercise in state-funded scientific rationality. When Maupertuis returned to Paris, he ensured that the world properly appreciated his achievements by publishing a vivid account, imaginatively combining the genres of travelogue, 'boy's own' adventure story and popular science.

Maupertuis had survived the rigours of Lapland, but now he had to make credible the precision knowledge brought back from the Arctic. What was at issue in the measure of equatorial and Arctic degrees of latitude was the bitterly contested question of whether the shape of the Earth was oblate (flattened at the poles), as Maupertuis maintained, or prolate (elongated at the poles), as was claimed by his local enemies in the Paris Academy of Sciences, the Cassini dynasty of astronomers. The problem of the Earth's exact shape was pertinent to practical cartography and navigation, but it was also connected in complicated ways to preferences for newtonian or cartesian theories of gravitation in particular, and philosophies of nature in general.

For Enlightenment men of science working in absolutist political settings, the question of the credibility of scientific knowledge was always linked to the security of their scientific careers. Science played to the sovereign and his courtiers, and without their approval there were limited resources to do research, few institutional stipends to sustain them, and only weak or marginalized cultural allies to support scientific positions. Part of Maupertuis' genius lay in the deft way that he kept audiences of scientific experts and polite society both in play. As Mary Terrall writes, after many years, Maupertuis refined “an identity as a public figure equally at home in academy and salon”.

When he returned from Lapland, Maupertuis was celebrated by both the court and the salons, falling into the arms of a series of married aristocratic literary ladies, whom he serenaded on his guitar, and securing a pension from the crown for his services to the state. He had his portrait painted dressed in exotic Lapp costume, with his left hand flattening the North Pole of a globe, just so no one could possibly miss the point. He never forgot the importance of amusing as well as instructing, and his literary merits were certified in 1743 by election to the Académie française, thus becoming an 'immortal', and one of the very few French men of science honoured by the élite academies of both of the 'two cultures'.

Having achieved all he could in Paris, Maupertuis was now tempted by Louis XV's absolutist rival, Frederick the Great, who wished his court in Berlin to be furnished and burnished by the best Enlightenment literati that money could buy. Frederick wanted Maupertuis to take charge of the Berlin Academy of Sciences, but the Prussian king's first approaches were rebuffed. Maupertuis eventually succumbed in 1745, seduced by the opportunity for dinner-table intimacy with a monarch, by the offer of total authority over the academy's affairs, by piles of cash, and possibly by Frederick's arrangement of a posh German wife for the now-47-year-old French bachelor savant.

Exile to the Prussian cultural hinterlands turned out to have limited charms for Maupertuis. He never mastered the language; he was irritated by German philosophers' preference for Christian Wolff's version of leibnizian metaphysics; and he got caught up in a nasty, and ultimately petty, polemical exchange with Voltaire, Frederick's other prize French catch. His health already suffering from the Prussian climate, Maupertuis faced personal disaster when Frederick and Louis, the two absolutist sovereigns to whom he owed allegiance, went to war with each other in 1756. Maupertuis died three years later, fittingly in Basel, about halfway between Paris and Berlin.

Maupertuis' life exposes some of the tensions that existed between the cultural powers of princely patronage and Enlightenment ideals of intellectual republicanism. This well-crafted biography is one of the better studies of the problems and opportunities of the eighteenth-century scientific career under the conditions of absolutism.