Jean Baptiste Joseph Delambre

Not to be confused withd'Alambert.

Jean Baptiste Joseph Delambre
Born	(1749-09-19)19 September 1749 Amiens,Kingdom of France
Died	19 August 1822(1822-08-19)(aged 72) Paris,Kingdom of France
Scientific career
Fields	Astronomy
Doctoral advisor	Jérôme Lalande
Doctoral students	Gerard Moll

Jean Baptiste Joseph, chevalier Delambre(19 September 1749 – 19 August 1822) was a French mathematician,astronomer,historian of astronomy,andgeodesist.He was also director of theParis Observatory,and author of well-known books on the history ofastronomyfrom 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 unpublishedRègle ou méthode facile pour apprendre la langue anglaise(Easy rule or method for learning English).

Delambre's quickly achieved success in his career in astronomy, such that in 1788, he was elected a foreign member of theRoyal Swedish Academy of Sciences.In 1790, to establish a universally accepted foundation for the definition of measures, theNational Constituent Assemblyasked theFrench Academy of Sciencesto introduce a new unit of measurement. 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 themeridian arcbetweenDunkirkandBarcelona.This portion of themeridian,which also passes through Paris, was to serve as the basis for the length of the quarter meridian, connecting theNorth Polewith theEquator.In April 1791, the academy's Metric Commission confided this mission toJean-Dominique de Cassini,Adrien-Marie LegendreandPierre 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 KingLouis XVIon hisFlight to Varennes.On 15 February 1792, Delambre was elected unanimously a member of theFrench Academy of Sciencesand in May 1792, after Cassini's final refusal, was placed in charge of the northern expedition, measuring the meridian from Dunkirk toRodezin the south of France.Pierre Méchainheaded 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 ConsulBonapartetook the presidency of theFrench Academy of Sciencesand appointed Delambre its Permanent Secretary for the Mathematical Sciences, a post he held until his death. In 1803, he was elected a member of theAmerican Philosophical SocietyinPhiladelphia.

After Méchain's death in 1804, he was appointed director of theParis Observatory.He was also professor of astronomy at theCollège 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 andgeodeticalsurveys, 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 ofDelambre's analogiesand, after the age of 70, also the author of works on thehistory of astronomylike theHistoire de l'astronomie.He was a knight (chevalier) of theOrder of Saint Michaeland of theLégion d'honneur.His name is also one of the72 names inscribed on the Eiffel tower.He was elected a Foreign Honorary Member of theAmerican Academy of Arts and Sciencesin 1822.

Delambre died in 1822 and was interred inPère Lachaise Cemeteryin Paris. The craterDelambreon the Moon is named after him.

Delambre was an atheist.

Works

Histoire de l'astronomie ancienne, 1817

Title page of an 1817 copy of "Tables écliptiques des satellites de Jupiter"

• 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)
• 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)
• 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^meV^eCourcier, 1817. 2 volumes; vol. 1, lxxii, 556 pp., 1 folded plate; vol. 2, viii, 639 pp., [1], 16 folded plates.OCLC490232972.
    Reprinted by New York and London: Johnson Reprint Corporation, 1965 (Sources of Science,#23), with a new preface by Otto Neugebauer.OCLC648488.
    Text on line: vol. 1,[1],[2],[3];vol. 2,[4],[5].
  • Histoire de l'astronomie du moyen age,Paris: M^meV^eCourcier, 1819. lxxxiv, 640 pp., 17 folded plates.OCLC490233042.
    Reprinted by New York and London: Johnson Reprint Corporation, 1965 (Sources of Science,#24.)OCLC647834.
    Also reprinted by Paris: J. Gabay, 2006.OCLC494627038.
    Text on line:[6].
  • Histoire de l'astronomie moderne,Paris: M^meV^eCourcier, 1821. 2 volumes; vol. 1, lxxxii, 715 pp., [1], 9 folded plates; vol. 2, [4], 804 pp., 8 folded plates.OCLC490233154.
    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.OCLC647838.
    Also reprinted by Paris: Editions Jacques Gabay, 2006.OCLC493779358.
    This takes the history to the 17th century.
    Text on line: both volumes, with usable plates,[7];vol. 1,[8],[9],[10];vol. 2,[11].
  • Histoire de l'astronomie au dix-huitième siècle,edited by Claude-Louis Mathieu, Paris: Bachelier (successeur de M^meV^eCourcier), 1827. lii, 796 p., 3 folded plates.OCLC490233264
    Reprinted by Paris: J. Gabay, 2004.OCLC470502171.
    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.
    Text on line:[12];with usable plates,[13].
• Grandeur et figure de la terre, ouvrage augmenté de notes, de cartes (1912)(edited by Guillaume Bigourdan, Gauthiers-Villars, Paris, 1912; about thefigure of the Earth)

Some works are digitalizedonParis Observatorydigital library.

• 
  1817 copy of "Tables écliptiques des satellites de Jupiter"
• 
  1817 introduction to "Tables écliptiques des satellites de Jupiter"
• 
  1817 introduction to "Tables écliptiques des satellites de Jupiter"
• 
  1817 introduction to "Tables écliptiques des satellites de Jupiter"
• 
  Excerpt from an 1817 copy of "Tables écliptiques des satellites de Jupiter"

See also

• Delambre analogies
• History of the metre
• Arc measurement of Delambre and Méchain
• Seconds pendulum

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;ISBN0-7432-1675-X)

External links

• Media related toJean-Baptiste Joseph Delambreat Wikimedia Commons

• O'Connor, John J.;Robertson, Edmund F.,"Jean Baptiste Joseph Delambre",MacTutor History of Mathematics Archive,University of St Andrews
• 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
• Portrait of Jean Baptiste Joseph Delambre from the Lick Observatory Records Digital Archive, UC Santa Cruz Library's Digital CollectionsArchived15 December 2018 at theWayback Machine
• Jean Baptiste Joseph Delambre papers Jean Baptiste Joseph Delambre papers, MSS 458atL. Tom Perry Special Collections,Brigham Young University
• Delambre's publicationson Paris Observatory digital library (in French)