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#REDIRECT [[Bureau des Longitudes]]
The '''Bureau of Longitude''' was a department of the [[Politics of France|French government]] created on [[June 25]], [[1795]] to improve knowlege about the [[longitude]]s of the [[sea]], difference in [[time]], and [[stellar astronomy|astronomical tables]]. During the [[19th Century]], it was responsible for [[Clock signal|synchornizing]] [[clocks]] across the world. It was headed during this time by [[François Arago]] and [[Henri Poincaré]]. The Bureau now functions as an [[academy]] and still meets monthly to discuss topics related to [[astronomy]].
The Bureau was founded by the [[National Convention]] after it heard a report drawn up jointly by the Committee of Navy, the Committee of Finances and the Committee of State education. The Bureau was charged with taking control of the seas away from the [[English]] and improving accuracy when trackinng the longitudes of ships through astronomical observations and reliable clocks. The ten original members of the Bureau were "geometricians" [[Joseph Louis Lagrange|Lagrange]], and [[Pierre-Simon Laplace|Laplace]]; the famous [[astronomers]] [[Joseph Jerôme Lefrançais de Lalande|Lalande]], [[Jean Baptiste Joseph Delambre|Delambre]], [[Pierre Méchain|Méchain]] and [[Giovanni Cassini|Cassini]]; [[Louis Antoine de Bougainville|Bougainville]], celebrated [[navigator]]; Bordered, who carried out work related to the [[mechanics]] of the [[fluids]] and precusor of [[Lazare Carnot|Carnot]] because of his insights on [[thermodynamics]]; Buache, [[geographer]]; and Caroché, [[manufacturer]] of [[telescopes]].
The [[decree]] of [[January 30]], [[1854]] modified the Bureau of Longitude significantly. It granted independence to the [[Paris Observatory]], seperating it from the Bureau, and focused the efforts of the Bureau on [[time]] and [[astronomy]]. The Bureau was successful setting a universal time in Paris via air pulses sent through [[pneumatic tubes]]. It later worked to synchronize time across the [[French Empire]] by determining the length of time for a signal to make a round trip to and from a French [[colony]].
The French Bureau of Longitude established a commission in the year [[1897]] to extend the [[SI|metric system]] to the measurement of [[time]]. They planned to abolish the antiquated division of the day into [[hour]]s, [[minute]]s, and [[second]]s, and replace it by a division into tenths, thousandths, and hundred thousandths of a [[day]]. This was a revival of a [[dream]] that was in the minds of the creators of the metric system at the time of the [[French Revolution]] a hundred years earlier. Some members of the Bureau of Longitude commission introduced a compromise proposal, retaining the old-fashioned hour as the basic unit of time and dividing it into hundredths and ten thousandths. Poincaré served as secretary of the commission and took its work very seriously, writing several of its reports. He was a fervent believer in a [[physical unit|universal metric system]]. But he lost the battle. The rest of the world outside France gave no support to the commission's proposals, and the French government was not prepared to go it alone. After three years of hard work, the commission was dissolved in 1900.
==References==
*[http://www.bureau-des-longitudes.fr/ Bureau Des Longitudes] (French)
*[[Peter Galison]], author of ''[[Einstein's Clocks, Poincaré's Maps]]''
*Dyson, Freeman J. (November 6, 2003). [http://www.nybooks.com/articles/article-preview?article_id=16739 Clockwork Science]. ''The New York Review of Books'' 50 (17)
* [http://perso.wanadoo.fr/cadastre/longitude.htm The Office of Longitudes]
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