composed of Gabriel Císcar, Jean-Baptiste Delambre, Pierre- Simon Laplace, Adrien-Marie Legendre, Pierre Méchain, Jean Henri van Swinden and Johann Georg Tralles combined the results of the survey with those of the Geodetic Mission to Peru and found a value of 1/334 for the Earth's flattening. They then extrapolated from the measurement of the Paris meridian arc between Dunkirk and Barcelona the distance from the North Pole to the Equator which was 5,130,740 toises. As the metre had to be equal to one ten-millionth of this distance, it was defined as 0.513074 toise or 3 feet and 11.296 lines of the Toise of Peru. Their result came out at 0.144 shorter than the provisional value, a difference of about 0.03%. While Méchain and Delambre were completing their survey, the commission had ordered a series of platinum bars to be made based on the provisional metre. When the final result was known, the bar whose length was closest to the meridional definition of the metre was selected and placed in the National Archives on 22 June 1799 (4 messidor An VII in the Republican calendar) as a permanent record of the result. This standard metre bar became known as the . The metric system, that is the system of units based on the metre, was officially adopted in France on 10 December 1799 (19 frimaire An VIII) and became the sole legal system of weights and measures from 1801. After the restoration of the Empire, in 1812, the old names for units of length were revived but the units redefined in terms of the metre: this system was known as , and lasted until 1840, when the decimal metric system was again made the sole legal measure. In the meantime, the Netherlands had adopted the metric system from 1816. The first of several countries to follow the French lead, the Helvetic Republic had adopted the metre shortly before its collapse in 1803. With the extension of the survey it became apparent that Méchain and Delambre's result (443.296 ) was slightly too short for the meridional definition of the metre. While the Ordnance Survey extended the British survey northward to the Shetland Islands, Arago and Biot extended the survey southward in Spain to the island of Formentera in the western Mediterranean Sea (1806–1809), and found that one ten-millionth of the Earth's quadrant should be 443.31 : later work increased the value to 443.39