The arc measurement of Delambre and Méchain was a geodetic survey carried out by Jean-Baptiste Delambre and Pierre Méchain in 1792–1798 to measure an arc section of the Paris meridian between Dunkirk
The Panthéon in Paris. At the time of Jean-Baptiste Joseph Delambre, it served as a warehouse for all the old weights and measures which had been sent by towns throughout France in anticipation of the standardisation of weights and measures by the establishment of the new decimal metric system.
The triangulation mesh of the Anglo-French Survey (1784–1790).
Repeating circle devised by Jean-Charles de Borda and constructed by Étienne Lenoir
The free-standing belfry in Dunkirk on the French English Channel coast – the northerly end of the meridian survey of 1792–9
History of the metre
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During the French Revolution, the traditional units of measure were to be replaced by consistent measures based on natural phenomena. As a base unit of length, scientists had favoured the seconds pend
Replicas of historical metric standards, including an iron copy of the mètre des Archives.
A copy of the "provisional" metre located in the wall of a building, 15 rue de Vaugirard, Paris.
Closeup of National Prototype Metre Bar No. 27, made in 1889 by the International Bureau of Weights and Measures (BIPM) in collaboration with Johnson Mattey and given to the United States, which served as the standard for American cartography from 1890 replacing the Committee Meter, an authentic copy of the Mètre des Archives produced in 1799 in Paris, which Ferdinand Rudolph Hassler had brought to the United States in 1805.
A Krypton-86 lamp used to define the metre between 1960 and 1983