The French Expedition That Shaped the Earth

The French Expedition That Shaped the Earth

By Nick Dall


Because, in the end, science must prevail.

By Nick Dall

It had been two years since they left home, but their real journey was just beginning. In August 1737, French scientists, having traveled across the Atlantic to Ecuador, split into two groups and departed Quito for separate peaks. They would battle altitude sickness — a condition Europeans were oblivious to — and freezing cold to reach their respective summits and begin their work of triangulation.

At their destinations, the teams each erected a huge pyramid of wood and cotton that could be seen from 30 miles away. For 23 days straight, cloud, fog and mist prevented them from measuring a single angle, and they were forced to return to Quito no closer to their goal. The French Geodesic Mission to the Equator left France in 1735 to determine — enfin! — whether the Earth was squeezed at the Equator, as followers of René Descartes believed, or flattened at the poles, as English upstart Isaac Newton maintained.

Pierre Bouguer & Charles Marie de La Condamine

Charles-Marie de La Condamine (left) and Pierre Bouguer

Source Public Domain

How? By measuring the length of a degree of latitude at the equator and comparing the result to a measurement  already taken in Europe. If a degree at the equator was longer than one in Europe, Newton would be vindicated; shorter and Descartes’ supporters could crack open the Champagne. Akin to an 18th-century U.S.-Soviet space race, the expedition had political connotations aplenty, but the mission was about far more than solving a riddle; it also had military implications. It’s easier to conquer the world, after all, with accurate maps.

[The Frenchmen were] deskbound mathematicians who hadn’t the faintest clue what leadership meant.

Dr. Larrie D. Ferreiro, author and historian

Three French scientists — Pierre Bouguer, Louis Godin and Charles-Marie de La Condamine — were up against it from the moment they set off, according to Dr. Larrie D. Ferreiro in Measure of the Earth: The Enlightenment Expedition That Reshaped Our World. The Frenchmen were “deskbound mathematicians who hadn’t the faintest clue what leadership meant,” he says. Because Quito was under Spanish control, they were accompanied by two experienced but young (19 and 22, initially) Spanish naval officers who, as luck would have it, turned out to be the glue that held the whole thing together.


In a sign of things to come, it took the team 13 months just to reach Quito. After Godin spent a large chunk of the expedition’s funds on a diamond for a prostitute in Saint-Domingue (now Haiti), the French scientists had a huge bust-up at Manta, in modern-day Ecuador. There, La Condamine and Bouguer disembarked and continued on foot … before also splitting up. By the time the three factions arrived, they had burned through almost all of the expedition’s funds. If La Condamine hadn’t bailed out the expedition with his own money, the mission might never have gotten off the ground.

Over the next several years, everything that could go wrong did. They faced huge challenges in making measurements — scientists would have to climb 50 volcanoes and measure 50 angles to complete their calculations — but in Ferreiro’s assessment, the biggest setbacks were “self-inflicted wounds,” not scientific challenges. The gravest faux pas? When the expedition’s surgeon, Jean Seniergues, emboldened by a few too many glasses of aguardiente while in Cuenca in 1739, had the audacity to join his local lover in the very public setting of a bullfight … while she was sitting with her father. The situation escalated rapidly, with weapons drawn, insults hurled and a crowd of irate locals surrounding Seniergues, jabbing him with pikes and lances while shouting “Kill the French foreigners!” A week later, he died from his wounds, but the diplomatic fallout could have been far worse.

In spite of everything, the scientists were indeed able to ascertain that a degree of latitude at the equator measures 68.7 miles — we know they were accurate to within 50 yards, amazingly — confirming Newton’s theory and forever changing the way we see and think about the world. In 1743, the members of the expedition dispersed. Bouguer, who traveled via the Caribbean, was the first to make it back to France; Godin ended up taking a job in Lima, where he played a major role in rebuilding the city after the disastrous earthquake of 1746; and La Condamine returned via the Amazon, in the process penning one of the first scientific accounts of the world’s greatest river.

As well as reshaping the Earth, the expedition did a lot to mold a continent. Bouguer, La Condamine and both Spanish officers wrote books about their experiences, providing Europeans with some of the first observations of South America from a nonmilitary, nonreligious perspective.

Their writings painted a picture of South Americans as a brave and proud people that, ironically, half a century later, “filtered back to South America and acted as one of many catalysts that led to the independence wars that started in 1809,” observes Ferreiro. The great libertador Simón Bolívar even paid homage to two of the explorers in My Vision on Chimborazo. “I strove bravely forward in the footsteps of La Condamine and Humboldt, and nothing could hold me back,” he wrote.