Jean Baptiste Joseph, chevalier Delambre (September 19, 1749 -August 19, 1822) was a French mathematician and astronomer. In 1790, in order to establish a universally accepted foundation for the definition of measures, the National Constituent Assembly asked the French Academy of Sciences to introduce a new unit of measurement. They chose the meter, defined as 1/10,000,000 of the distance from the North Pole to the equator, and prepared to organize an expedition to measure the length of the meridian arc between Dunkirk and Barcelona. In 1792 Delambre was placed in charge of the northern expedition, measuring the meridian from Dunkirk to Rodez. In 1801 Napol矇on Bonaparte took the presidency of the French Academy of Sciences and appointed Delambre its Permanent Secretary for the Mathematical Sciences, a post he held until his death. In 1804, he was appointed director of the Paris Observatory and professor of Astronomy at the Coll癡ge de France. He was one of the first astronomers to derive astronomical equations from analytical formulas, was the author of Delambre's Analogies and, the author of works on the history of astronomy. He died in 1824 at the age of 72. His name is also one of the 72 names inscribed on the Eiffel tower.