French Geodesic Mission to Lapland

[1] By measuring the length of the arc, Maupertuis's team was able to prove that the Earth is, indeed, flattened at the poles as Sir Isaac Newton had predicted.

After arriving in Tornio in summer, the team moved north along the Meänmaa valley, making precise angle measurements between reference points to lay down a system of triangulations.

After analyzing their data, they found that the length of 1 degree of latitude to be 57,422 toise in Lapland.

Jean Picard had surveyed the Paris-Amiens region in 1669, finding a figure of 57,060 toise.

Maupertuis' Letter to James Bradley, third Astronomer Royal of Great Britain.Later, Euler used figures from these expeditions, as well as later data, to compute the shape of the Earth.