Dunkirk-Barcelona meridian measurement and the definition of the metre
Medición del meridiano Dunkerque-Barcelona y definición del metro
- Date
- 1792-1798 · confidence high
- Place
- Paris, Île-de-France, France
- Credited to
- Jean-Baptiste Delambre and Pierre Méchain
- Field
- Cosmos & Earth
What was discovered
Triangulation of the meridian arc between Dunkirk and Barcelona, from which one ten-millionth of the Earth's quadrant was taken to define the metre. It is the first length unit defined from a dimension of the Earth.
Méchain found an error in Barcelona's latitude and concealed it until his death. The defined metre turned out about 0.2 mm shorter than intended because of flattening and measurement errors.
What it led to
- the decimal metric system
- geodetic data on the Earth's flattening