Editing Jean Baptiste Joseph Delambre

{{Short description|French mathematician and astronomer (1749–1822)}}
{{EngvarB|date=July 2017}}
{{Use dmy dates|date=May 2024}}
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{{Infobox scientist
|name              = Jean Baptiste Joseph Delambre
|image             = File:Delambre Boilly crop.jpg
|image_size       = 250px
|caption           = 
|birth_date        = {{birth date|df=yes|1749|9|19}} 
|birth_place       = [[Amiens]], [[Kingdom of France]]
|death_date        = {{death date and age|df=yes|1822|8|19|1749|9|19}}
|death_place       = Paris, [[Bourbon Restoration in France|Kingdom of France]]
|field             = [[Astronomy]]
|work_institutions = 
|alma_mater        = 
|doctoral_advisor  = [[Jérôme Lalande]]
|doctoral_students = [[Gerard Moll]]
|known_for         = 
|author_abbrev_bot = 
|author_abbrev_zoo = 
|influences        = 
|influenced        = 
|prizes            = 
|footnotes         = 
|signature         =
}}
'''Jean Baptiste Joseph, chevalier Delambre''' (19 September 1749 – 19 August 1822) was a French mathematician, [[astronomer]], [[historian of astronomy]], and [[geodesist]].<ref name="Ten2014">{{cite book | last=Ten | first=Antonio E. | title=Biographical Encyclopedia of Astronomers | chapter=Delambre, Jean-Baptiste-Joseph | publisher=Springer New York | publication-place=New York, NY | year=2014 | isbn=978-1-4419-9916-0 | doi=10.1007/978-1-4419-9917-7_346 | pages=542–543}}</ref><ref name="Nature1912">{{cite journal | title=Grandeur et Figure de la Terre | journal=Nature | publisher=Springer Science and Business Media LLC | volume=90 | issue=2239 | year=1912 | issn=0028-0836 | doi=10.1038/090101a0 | pages=101| bibcode=1912Natur..90..101. | s2cid=29711903 }}</ref> He was also director of the [[Paris Observatory]], and author of well-known books on the history of [[astronomy]] from ancient times to the 18th century.

== 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recall entire pages verbatim weeks after reading them, became fluent in Italian, English and German and even wrote an unpublished ''Règle ou méthode facile pour apprendre la langue anglaise'' (Easy rule or method for learning English).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>

==Works==
[[File:Delambre, Jean Baptiste Joseph – Histoire de l'astronomie ancienne, 1817 – BEIC 618287.jpg|thumb|Histoire de l'astronomie ancienne, 1817]]
[[File:Delambre-3.jpg|thumb|Title page of an 1817 copy of "''Tables écliptiques des satellites de Jupiter''"]]
*[https://books.google.com/books?id=-jIVAAAAQAAJ Méthodes analytiques pour la détermination d'un arc du méridien] (Crapelet, Paris, 1799)
*''Notice historique sur M. Méchain, lue le 5 messidor XIII'' (Baudouin, Paris, January 1806; this is the eulogy on the late Pierre Méchain, read at the academy by Secretary Delambre on 24 June 1805)
*[https://books.google.com/books?id=6DEVAAAAQAAJ Base du système métrique décimal, ou Mesure de l'arc du méridien – compris entre les parallèles de Dunkerque et Barcelone, exécutée en 1792 et années suivantes, par MM. Méchain et Delambre.] (editor; Baudouin, Imprimeur de l'Institut National; Paris; 3. vol.; January 1806, 1807, 1810; this includes both his own and Méchain's data gathered during the meridian survey 1792–1799 and calculations derived thereof)
*''Rapport historique sur le progrès des sciences mathématiques depuis 1799'' (Imprimerie Impériale, Paris, 1810)
*''[https://catalog.hathitrust.org/Record/011678884?type%5B%5D=title&lookfor%5B%5D=Tables%20%C3%A9cliptiques%20des%20satellites%20de%20Jupiter&ft=ft Tables écliptiques des satellites de Jupiter: d'après la théorie de M. le Marquis de Laplace, et la totalité des observations faites depuis 1662 jusqu'à l'an 1802]'' (Paris : Courcier, 1817.)
*A history of astronomy, comprising four works and six volumes in all:
**''Histoire de l'astronomie ancienne'', Paris: M<sup>me</sup> V<sup>e</sup> Courcier, 1817.  2 volumes; vol. 1, lxxii, 556 pp., 1 folded plate; vol. 2, viii, 639 pp., [1], 16 folded plates. {{OCLC|490232972}}.<br />Reprinted by New York and London: Johnson Reprint Corporation, 1965 (''Sources of Science'', #23), with a new preface by Otto Neugebauer.  {{OCLC|648488}}.<br />Text on line: vol. 1, [https://books.google.com/books?id=4qoaAAAAYAAJ], [http://hdl.handle.net/2027/mdp.39015073350236], [http://hdl.handle.net/2027/mdp.39015077830456]; vol. 2, [https://books.google.com/books?id=km0rAAAAYAAJ], [http://hdl.handle.net/2027/mdp.39015077830464].
**''Histoire de l'astronomie du moyen age'', Paris: M<sup>me</sup> V<sup>e</sup> Courcier, 1819.  lxxxiv, 640 pp., 17 folded plates.  {{OCLC|490233042}}.<br />Reprinted by New York and London: Johnson Reprint Corporation, 1965 (''Sources of Science'', #24.)  {{OCLC|647834}}.<br />Also reprinted by Paris: J. Gabay, 2006. {{OCLC|494627038}}.<br />Text on line: [https://books.google.com/books?id=QREOAAAAQAAJ].
**''Histoire de l'astronomie moderne'', Paris: M<sup>me</sup> V<sup>e</sup> Courcier, 1821.  2 volumes; vol. 1, lxxxii, 715 pp., [1], 9 folded plates; vol. 2, [4], 804 pp., 8 folded plates.  {{OCLC|490233154}}.<br />Reprinted by New York and London: Johnson Reprint Corporation, 1969 (''Sources of Science'', #25), with a new introduction and tables of contents by I. Bernard Cohen.  {{OCLC|647838}}.<br />Also reprinted by Paris: Editions Jacques Gabay, 2006.  {{OCLC|493779358}}.<br />This takes the history to the 17th century.<br />Text on line: both volumes, with usable plates, [http://nrs.harvard.edu/urn-3:FHCL:2404611]; vol. 1, [http://hdl.handle.net/2027/mdp.39015017146823], [https://books.google.com/books?id=MKwaAAAAYAAJ], [https://books.google.com/books?id=yRAOAAAAQAAJ]; vol. 2, [https://books.google.com/books?id=hrUaAAAAYAAJ].
**''Histoire de l'astronomie au dix-huitième siècle'', edited by Claude-Louis Mathieu, Paris: Bachelier (successeur de M<sup>me</sup> V<sup>e</sup> Courcier), 1827.  lii, 796 p., 3 folded plates.  {{OCLC|490233264}}<br />Reprinted by Paris: J. Gabay, 2004.  {{OCLC|470502171}}.<br />This includes the history of astronomy in the 18th century, especially critiques of his colleagues at the academy, which he withheld to be published posthumously.<br />Text on line: [https://books.google.com/books?id=1EgtAAAAYAAJ]; with usable plates, [http://gallica.bnf.fr/ark:/12148/bpt6k61990q].
*[[iarchive:grandeuretfigure00dela|Grandeur et figure de la terre, ouvrage augmenté de notes, de cartes (1912)]](edited by Guillaume Bigourdan, Gauthiers-Villars, Paris, 1912; about the [[figure of the Earth]])
[https://bibnum.obspm.fr/ark:/11287/27xc8 Some works are digitalized] on [[Paris Observatory]] digital library.<gallery>
File:Delambre-1.jpg|1817 copy of "''Tables écliptiques des satellites de Jupiter''"
File:Delambre-4.jpg|1817 introduction to "''Tables écliptiques des satellites de Jupiter''"
File:Delambre-5.jpg|1817 introduction to "''Tables écliptiques des satellites de Jupiter''"
File:Delambre-6.jpg|1817 introduction to "''Tables écliptiques des satellites de Jupiter''"
File:Delambre-7.jpg|Excerpt from an 1817 copy of "''Tables écliptiques des satellites de Jupiter''"
</gallery>

== See also ==
* [[Spherical trigonometry#Delambre (or Gauss) analogies|Delambre analogies]]
* [[History of the metre]]
* [[Arc measurement of Delambre and Méchain]]
* [[Seconds pendulum]]

==References==
{{reflist}}

==Further reading==
* Ken Alder: ''The Measure of All Things – The Seven-Year Odyssey and Hidden Error That Transformed the World'' (The Free Press; New York, London, Toronto, Sydney, Singapore; 2002; {{ISBN|0-7432-1675-X}})

==External links==
*{{Commons category-inline}}
{{EB1911 poster|Delambre, Jean Baptiste Joseph|Jean Baptiste Joseph Delambre}}
* {{MacTutor Biography|id=Delambre}}
* [http://www.surveyhistory.org/jean_baptiste_delambre1.htm A brief biography of Delambre], partly from the 1880 Encyclopædia Britannica, including an account of Delambre's intervention to request liberation (from French imprisonment) of James Smithson, who went on to endow the foundation of the Smithsonian Institution, national museum of the United States of America
* [http://digitalcollections.ucsc.edu/cdm/compoundobject/collection/p265101coll10/id/1499/rec/1 Portrait of Jean Baptiste Joseph Delambre from the Lick Observatory Records Digital Archive, UC Santa Cruz Library's Digital Collections] {{Webarchive|url=https://web.archive.org/web/20181215171519/http://digitalcollections.ucsc.edu/cdm/compoundobject/collection/p265101coll10/id/1499/rec/1 |date=15 December 2018 }}
*[http://archives.lib.byu.edu/repositories/14/resources/7396 Jean Baptiste Joseph Delambre papers Jean Baptiste Joseph Delambre papers, MSS 458] at [https://sites.lib.byu.edu/sc/ L. Tom Perry Special Collections], [[Brigham Young University]]
*[https://bibnum.obspm.fr/ark:/11287/27xc8 Delambre's publications] on Paris Observatory digital library (in French)

{{Authority control}}

{{DEFAULTSORT:Delambre, Jean Baptiste Joseph}}
[[Category:1749 births]]
[[Category:1822 deaths]]
[[Category:People from Amiens]]
[[Category:19th-century French astronomers]]
[[Category:Burials at Père Lachaise Cemetery]]
[[Category:Knights of the Legion of Honour]]
[[Category:Academic staff of the Collège de France]]
[[Category:Fellows of the American Academy of Arts and Sciences]]
[[Category:Fellows of the Royal Society]]
[[Category:French atheists]]
[[Category:18th-century French astronomers]]
[[Category:19th-century French historians]]
[[Category:Historians of astronomy]]
[[Category:Members of the Royal Swedish Academy of Sciences]]
[[Category:Officers of the French Academy of Sciences]]
[[Category:18th-century French mathematicians]]
[[Category:19th-century French mathematicians]]
[[Category:French male writers]]
[[Category:19th-century French male writers]]
[[Category:French geodesists]]
[[Category:Honorary members of the Saint Petersburg Academy of Sciences]]
[[Category:International members of the American Philosophical Society]]