
The expedition on the map
The story of the expedition is recorded in the detailed journal entries on which Réginald Outhier based his Journal of a voyage to the North (Journal d’un voyage au Nord) from 1744. He also drew several maps for his work.
The maps on this page show a selection of the degree-measuring expedition’s journeys. The journey between Paris and Tornio took about two months in each direction. The expedition also spent two months crossing the Torne back and forth as they were building a chain of survey triangulations.
Spring and early summer 1736 | Journey from Paris to Tornio

The expedition set off from Paris at the end of April 1736 and arrived in Tornio by Midsummer. The journey was made by boat and carriage.
In his book, Outhier describes the journey in detail, stage by stage. The road north from Stockholm was beautiful and well maintained. Every 2.5 kilometres or so, there was a red wooden pole along the road indicating the distance to Stockholm.
On the coast, there were no bridges over the rivers that flowed into the sea. The rivers were crossed on ferries, which slowed down the journey.
The first to arrive was a servant on horseback to announce the arrival of the carriages. Then the first carriage announced that the second carriage would arrive in about eight hours. This allowed the stables to prepare for the travellers and arrange for the horses, which made the journey quicker.
People travelling from one province to another had to report to the governor, including the members of the French expedition.
After reaching their destination in Tornio, the French rested for two days from the stresses of the journey.
Summer 1736 | Construction of the chain of survey triangulations in the Torne Valley

When they arrived in Tornio after two months of travelling, the members of the expedition rested for a few days. Then the planning work began.
At the beginning of July, the expedition decided to carry out a triangulation in the hills of the Torne Valley. The original plan had been to build a chain of triangles on the islands along the coast of the Bay of Bothnia. However, the islands proved to be too low.
In the summer of 1736, the French were moving back and forth between the measurement points, moving steadily northwards. New measurement points were sought and markers were set up in smaller groups. All the time, a number of local workers helped with the process.
The map shows extracts from the construction of the chain of survey triangulations. Later in the autumn, the expedition returned to the northern end of the chain in Pello to take astronomical measurements.
Autumn and winter 1736–1737 | Astronomical measurements in Pello and Tornio, baseline measurement in Ylitornio

In the autumn, the expedition took astronomical measurements in Pello and Tornio. Using the stars, they determined the positions of the ends of the chain of survey triangulations on the latitude.
In December, a baseline was measured in Ylitornio. The expedition spent the long and cold winter mainly in Tornio. During the winter, they had time to socialise with the locals.
Spring and summer 1737 | Return journey from Tornio to Paris

Once the sea had thawed and travel by boat was possible, the expedition began to make its way back to France.
Johan Wegelius, the schoolmaster and curate of Tornio, had written a poem in honour of the French, which he recited to the expedition members before they left. In Tornio, too, people said goodbye to the people they had become acquainted with in the form of parties.
Two maps of the Torne
Outhier drew a beautiful map of Torne and the triangulation chain between Tornio and Pello. Carte du Fleuve de Torneå, or map of the Torne, was published as part of his journal.
Want a map for yourself? The map is currently sold as a poster (225 mm x 707 mm) in the shop of the Museum of Torne Valley (address Torikatu 4, Tornio).

The following map was published in Maupertuis's book La figure de la Terre (1738).

These and other Outhiers maps can be downloaded here. Unfortunately the page is currently only in Finnish.
Extracts from the maps
The purpose of the expedition. The purpose of Maupertuis' degree-measuring expedition was to clarify information about the shape of the Earth. The more accurately the Earth's dimensions were known, the more accurately maps could be drawn. The geometric accuracy of maps began to develop in Europe in the 15th century: the growth of shipping during the Age of Discovery accelerated the development.
Lack of accurate maps. The Maupertuis expedition could not plan their measurements precisely in advance because they did not have access to accurate maps of the northern regions. In Stockholm, they obtained a map of the coastline of the bottom of the Bay of Bothnia from the land survey office. The expedition had originally planned to take measurements on islands in the Bay of Bothnia, but the islands turned out to be too low.
Cartographer Outhier. During the trip, Outhier drew several maps, including ones of the Torne Valley, Pello, Tornio and Piteå. They were the most accurate maps of these areas at their time. In Piteå, for example, Outhier walked the silent streets of the town at night, measuring their lengths with his steps.