Editing Jean Baptiste Joseph Delambre (section)

== Biography ==

After a childhood fever, he suffered from very sensitive eyes, and believed that he would soon go blind. For fear of losing his ability to read, he devoured any book available and trained his memory.  He thus immersed himself in Greek and Latin literature, acquired the ability to recall entire pages verbatim weeks after reading them, became fluent in Italian, English and German and even wrote an unpublished ''Règle ou méthode facile pour apprendre la langue anglaise'' (Easy rule or method for learning English).

Delambre quickly achieved success in his career in astronomy, such that in 1788, he was elected a foreign member of the [[Royal Swedish Academy of Sciences]].  In 1790, to establish a universally accepted foundation for the definition of measures, the [[National Constituent Assembly (France)|National Constituent Assembly]] asked the [[French Academy of Sciences]] to introduce a new unit of [[length]]. The academics decided on the [[metre]], defined as 1 / 10,000,000 of the distance from the North Pole to the equator, and prepared to organise an expedition to measure the length of the [[meridian arc]] between [[Dunkirk]] and [[Barcelona]]. This portion of the [[meridian (geography)|meridian]], which also passes through Paris, was to serve as the basis for the length of the quarter meridian, connecting the [[North Pole]] with the [[Equator]]. In April 1791, the academy's Metric Commission confided this mission to [[Dominique, comte de Cassini|Jean-Dominique de Cassini]], [[Adrien-Marie Legendre]] and [[Pierre Méchain]]. Cassini was chosen to head the northern expedition but, as a royalist, he refused to serve under the revolutionary government after the arrest of King [[Louis XVI]] on his [[Flight to Varennes]]. On 15 February 1792, Delambre was elected unanimously a member of the [[French Academy of Sciences]] and in May 1792, after Cassini's final refusal, was placed in charge of the northern expedition, measuring the meridian from Dunkirk to [[Rodez]] in the south of France. [[Pierre Méchain]] headed the southern expedition, measuring from Barcelona to Rodez. The measurements were finished in 1798. The gathered data were presented to an international conference of savants in Paris the following year.

In 1801, [[First Consul]] [[Napoleon|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 1803, he was elected a member of the [[American Philosophical Society]] in [[Philadelphia]].<ref>{{Cite web|title=APS Member History|url=https://search.amphilsoc.org/memhist/search?creator=+Delambre&title=&subject=&subdiv=&mem=&year=&year-max=&dead=&keyword=&smode=advanced|access-date=2021-04-01|website=search.amphilsoc.org}}</ref>

After Méchain's death in 1804, he was appointed director of the [[Paris Observatory]]. He was also professor of astronomy at the [[Collège de France]]. The same year he married Elisabeth-Aglaée Leblanc de Pommard, a widow with whom he had lived already for a long time. Her son, Achille-César-Charles de Pommard (1781–1807) assisted Delambre on several occasions in his astronomical and [[geodesy|geodetical]] surveys, notably the measuring of the baselines for the meridian survey, and the latitude definition for Paris in December 1799 which was presented to the Conference of Savants.

Delambre was one of the first astronomers to derive astronomical equations from analytical formulas, was the author of [[Delambre's analogies]] and, after the age of 70, also the author of works on the [[history of astronomy]] like the ''Histoire de l'astronomie''.  He was a knight (''chevalier'') of the [[Order of Saint Michael]] and of the [[Légion d'honneur]].  His name is also one of the [[The 72 names on the Eiffel Tower|72 names inscribed on the Eiffel tower]]. He was elected a Foreign Honorary Member of the [[American Academy of Arts and Sciences]] in 1822.<ref name=AAAS>{{cite web|title=Book of Members, 1780–2010: Chapter D|url=http://www.amacad.org/publications/BookofMembers/ChapterD.pdf|publisher=[[American Academy of Arts and Sciences]]|access-date=28 July 2014}}</ref>

Delambre died in 1822 and was interred in [[Père Lachaise Cemetery]] in Paris.  The crater [[Delambre (crater)|Delambre]] on the Moon is named after him.

Delambre was an atheist.<ref>George William Foote, ed. (1887). Progress: a monthly magazine of advanced thought, Volume 7. Progressive Publishing Co. p. 127. DELAMBRE (Jean Baptiste Joseph), French astronomer, born at Amiens, 19 September 1749, studied under Lalande and became, like his master, an Atheist.</ref>