Jean Baptiste Joseph Delambre (September 19, 1749 in Amiens – August 19, 1822 in Paris) was a French mathematician and astronomer.

Delambre was born in Amiens, France. In collaboration with Pierre Méchain, his greatest achievement was the measurement of the length of the meridian between Dunkerque and Barcelona. This portion of the meridian, which also passes through Paris, was to serve as a basis for the calculation of the length of the quarter meridian, connecting the North Pole with the Equator. The expedition lasted from 1792 to 1799. Its purpose was to establish a universally accepted foundation for the definition of the metre, which was to be defined as 1 / 10,000,000 of the distance from the North Pole to the equator.

Delambre crater is named for him on the Moon.

External links

• http://www.surveyhistory.org/jean_baptiste_delambre.htm
• http://www-gap.dcs.st-and.ac.uk/history/Mathematicians/Delambre.html

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