AN ADVENTURE OF HISTORIC MEASURES.

• Author: Taylor, David
• Position: An exhibition to determine the dimensions of the earth

Although failing to determine the earth dimensions, the scientific expedition led by Charles-Marie de La Condamine revealed little-known marvels of South America

In the bustling heart of modern Quito, the Parque Alameda holds a quiet reminder of a journey that blended Enlightenment with adventure. Before the old observatory, amid streetside photographers booths, a circle of six gray stone busts portrays the members of the Geodesic Expedition of 1736-44--the first scientific expedition from Europe to South America. Led by a former soldier and friend of Voltaire, this group of French and Spanish scientists set out to solve an international puzzle about the shape of the earth. This aim would pit them against intrigues, malaria, huge cultural chasms, and murderous jealousy.

After Copernicus, a question that absorbed scientists was the earth's precise shape. By then it seemed clear from imperfections in navigation that the world was not a perfect sphere. In 1687, Sir Isaac Newton postulated that the diameter through the equator was slightly greater than its axis through the poles, like a squashed grapefruit. In France, the astronomer Gian Domenico Cassini and his son Jacques disagreed: Their measurements of the length of one meridian degree north of Paris and one south of Paris suggested that the equatorial axis was shorter than the polar axis--the opposite of Newton's theory.

The bickering across the English Channel in the name of science lasted for years after both Newton and Cassini had died. Finally, in 1735, the French Academy of Sciences dispatched two expeditions to settle the issue. One would journey north to Lapland (in present-day Sweden and Finland) to measure the length of a meridian degree there. The second, led by Charles-Marie de La Condamine, would do the same at the equator near Quito, in what was then the viceroyalty of Peru. Using both sets of measurements and convoluted calculations, scientists would calculate the earth's diameter on both axes and solve the riddle.

La Condamine might not seem an obvious choice to lead a scientific inquiry: A young aristocrat, he had shown bravery as an eighteen-year-old soldier in the siege of Rosas, in northeastern Spain, in 1719. His biggest accomplishment had been a tour de force of insider trading: When Paris launched a monthly lottery in 1728, he helped his friend Voltaire calculate that if a group bought all the lottery tickets, it could still make a profit from the winnings. Together, their syndicate carried off this sure-win scheme for at least ten months, raking in up to 7.5 million francs of prize money before closing the lottery down in June 1730. In journeys to the Middle East he had also proven to be a capable mathematician and astronomer, as well as an observant traveler.

In fact, La Condamine didn't join the expedition as its leader. That role was taken by the astronomer Louis Godin. Only later, when Godin became overbearing, did La Condamine and a gifted mathematician named Pierre Bouguer step in to manage the task together. Bouguer, a frail academic, hadn't planned on joining the expedition at all; he was recruited at the last minute as a replacement. Amid the frenzied preparations, they received a surprising and invaluable aid: a letter from Spain's King Philip V, granting safe passage and consideration in the Spanish colonies. (The interests of France and Spain found rare common ground in a shared, grievance against the Hapsburgs; the fact that Philip was grandson of the French Louis XIV also helped.) Philip provided an escort of two Spanish naval officers skilled in mathematics, who could also keep an eye on the Frenchmen. On April 14, 1735, the French expedition left Paris for Quito. The Spanish officers, Antonio de Ulloa and Jorge Juan y Santacilia, left from Cadiz.

After fourteen months, stops in Martinique and Cartagena, and a portage across the Panama isthmus, they rendezvoused in the Quito valley in June 1736. Bells rang from the city's elaborate church towers. Children in blue tunics waved bright flags of welcome, and the scientists were greeted by the president of the audiencia, Don Dionisio de Alcedo y Herrera. The visitors found a colonial society sharply and visibly stratified: One-sixth of the thirty-five thousand citizens were Spaniards, whose men wore black cloaks down to the knees; one-third were...