Why Famous: Influential French mathematician and astronomer who was a major figure in the establishment of the new metric system in France.
In 1792 Delambre was commissioned to measure part of the meridian, to discover a more accurate measurement of the metre after the French had decided on a new metric system of weights and measures in 1790. Despite delays because of the French revolution, and being mistaken for a spy, Delambre finished his part in 1797 and reported his findings in 1799.
In 1801 he was appointed secretary to the Académie des Sciences. He was also director of the Paris Observatory, and wrote a number of well-known books on the history of astronomy.
- 1792-05-05 Jean Baptiste Joseph Delambre commissioned to measure the meridian between Dunkerque to Rodez to calculate accurate length of the metre
- 1795-04-07 France adopts the metre as the basic measure of length