The Figure of the Earth

Summer 1736: a handful of French academicians land at Tornio, at the head of the Gulf of Bothnia, to settle the quarrel dividing learned Europe. Is the Earth flattened at the poles, as Newton holds, or elongated, as Cassini's measurements maintain?

At their head is Pierre Louis Moreau de Maupertuis. With Clairaut, Camus, Le Monnier, Abbé Outhier and the Swede Celsius, he goes up a river bristling with cataracts, crosses forests and marshes, and raises his signals from summit to summit to cast a chain of triangles across Lapland. The flies are so cruel that they drive the Lapps and their reindeer down to the sea; the scholars wrap themselves in skins and smoke to make their observations. One evening, the mountain of Horrilakero bursts into flames before their eyes.

Then comes winter. On 21 December, the day of the solstice, the party begins to measure its baseline on the ice of the river, so far from the sun that it shows itself only for a moment around noon. At Tornio, the mercury thermometers fall to 37 degrees below zero and the spirit of wine freezes.

As much an adventure narrative as a scientific report, this account tells how a measurement wrested from the Far North changed the image of our planet. But what is a figure obtained at the end of the world worth, and who will agree to believe it?