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Topic: Francois Arago


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In the News (Wed 16 Dec 09)

  
  François Arago - Wikipedia, the free encyclopedia
Arago was elected a member of the Bureau des Longitudes immediately afterwards, and contributed to each of its Annuals, for about twenty-two years, important scientific notices on astronomy and meteorology and occasionally on civil engineering, as well as interesting memoirs of members of the Academy.
Arago's earliest physical researches were on the pressure of steam at different temperatures, and the velocity of sound, 1818 to 1822.
Arago is also fairly entitled to be regarded as having proved the long-suspected connexion between the aurora borealis and the variations of the magnetic pa ments[?].
en.wikipedia.org /wiki/Fran%C3%A7ois_Arago   (2182 words)

  
 ARAGO, D.F.J. - LoveToKnow Article on ARAGO, D.F.J.   (Site not responding. Last check: 2007-10-29)
Pi ARAGO, DOMINIQUE FRAN~OIS JEAN (17861853), French of ysicist, was born on the 26th of February 1786, at Estagel, a fall village near Perpignan, in the department of the eastern m rrenees.
Arago was elected a member the Board of Longitude immediately afterwards, and contrited to each of its Annuals, for about twenty-two years, portant scientific notices on astronomy and meteorology d occasionally on.
Arago is also fairly entitled ar be regarded as having proved the long-suspected connection th tween the aurora borealis and the variations of the magnetic pa ments.
www.1911encyclopedia.org /A/AR/ARAGO_D_F_J_.htm   (2529 words)

  
 Arago   (Site not responding. Last check: 2007-10-29)
As an astronomer, Arago is remembered as the discoverer of the solar chromosphere and for his accurate measurements of the diameters of the planets.
Arago's test for comparing the velocity of light in air and in water or glass was described in 1838, but the experiment required such elaborate preparation that Arago was not ready to perform until 1850, when his sight failed.
Seems that Arago was the first man to build consciounsly an electromagnet, in September 1820, in the same time he noticed that rhe iron became a magnet only during the flow of current, the effect finished when the current stopped: the basis of Morse telegraph.
chem.ch.huji.ac.il /~eugeniik/history/arago.html   (1705 words)

  
 Arago, Dominique François Jean (1786-1853)
During the solar eclipse of 1842, he examined polarized light from the chromosphere and corona, and determined that the Sun’s limb is gaseous.
Arago suggested that his student Urbain Leverrier investigate irregularities in the orbit of Uranus and, after Neptune was discovered, took part in the argument regarding naming the planet and, with John Adams, regarding priority.
Arago also wrote about the possibility of life on comets: "I do not pretend to draw from these considerations the conclusion that comets are populated by beings of our species.
www.daviddarling.info /encyclopedia/A/Arago.html   (388 words)

  
 François Arago
François Arago was a French physicist and astronomer who made major contributions to the early study of electromagnetism including the phenomenon of magnetic rotation and the fact that a wire coil could be magnetized by passing electrical current through it.
Arago’s studies in astronomy included investigations of the solar corona and chromosphere, measurements of the diameters of the planets, and a theory that light interference is responsible for the twinkling of stars.
Arago was also active politically for France's leftist republican cause, serving several political roles in government in addition to his scientific duties (which included Director of the Paris Observatory).
www.nndb.com /people/308/000032212   (338 words)

  
 Arago
Arago made early discoveries on the corpuscular theory of light in 1811.
Arago carried out further experiments of this type and demonstrated several effects which led Faraday later to explain them as induction.
Working with Biot Arago made measurements of arc length on the Earth which led to the standardisation of the metric system of lengths.
www-history.mcs.st-and.ac.uk /history/Mathematicians/Arago.html   (361 words)

  
 Dominique Francois Arago   (Site not responding. Last check: 2007-10-29)
Seems thet Arago was the first man to build consciounsly an electromagnet, in september 1820, in the same time he noticed that rhe iron became a magnet only during the flow of current, the effect finished when the current stopped: the basis of Morse telegraph.
Arago had also discovered, in 1824, that a disk of non-magnetic metal had the power of bringing a vibrating magnetic needle suspended over it rapidly to rest; and that on causing the disk to rotate the magnetic needle rotated along with it.
When both were quiescent, there was not the slightest measurable attraction or repulsion exerted between the needle and the disk; still when in motion the disk was competent to drag after it, not only a light needle, but a heavy magnet.
www.geocities.com /SiliconValley/Circuit/1858/aragoe.htm   (292 words)

  
 Welcome to Adobe GoLive 5
Arago’s career as both an astronomer and a politician was impressive—he helped outlaw slavery in the French colonies, for example.
Arago’s contribution, while he was still a student at the Ecole Polytechnique in 1806, was to re-measure and extend the Paris Meridian all the way to Les Iles Baléares in Spain.
After being held prisoner by pirates, Arago completed the operation in 1809, returning to Paris to be elected to the Académie des Sciences at the ripe old age of 23 and later, head of the Paris Observatory.
perso.wanadoo.fr /ethan.gilsdorf/diskdials.htm   (2360 words)

  
 No. 1302: Marcet's Steam Globe
François Arago of the French Academy of Sciences had done the same experiment three years earlier.
Arago mounted sections of pipe up the side of a church tower and managed to measure water-vapor pressures to 24 atmospheres.
She was well-connected, and Arago was one of her European scientific friends.
www.uh.edu /engines/epi1302.htm   (570 words)

  
 In the Footsteps of Arago: The Scientific Tourist in the Balearic Islands   (Site not responding. Last check: 2007-10-29)
Arago and Biot had to light a bonfire on a mountain peak and attempt to view this at night from another peak to obtain their triangulation readings.
Arago and Biot's labours confirmed the accuracy of the original measurements; in the end the prototype metre differed from the original meridian definition by just 0.02%.
Today, Arago is honoured in Paris with the Arago monument: a trail of plaques let into the pavements of the city to mark the path of the meridian he plotted.
lec.ugr.es /~julyan/arago.html   (1147 words)

  
 Arago, Francois Jean   (Site not responding. Last check: 2007-10-29)
Though dead little over half a century, Arago is a marked example of the way in which eminent men and eminent services pass from the public mind.
As a student, director of the Observatory of Paris, editor of the Annals of Chemistry and Physics, member of the Chamber of Deputies, Minister of War and Navy, professor in the Polytechnical School and secretary of the French Academy of Sciences, he was a brilliant, able, prominent figure for half a century.
In the discharge of legislative and administrative duties to which he was called, Arago was influential in establishing public education, in the development of railroads and telegraphs, in improving the navigation of the Seine, and in the boring of artesian wells.
www.factopia.com /aiton-encyclopedia-vol1/arago-francois-jean.htm   (211 words)

  
 Seeing is Believing
The process that became known as the daguerreotype was first announced early in 1839 to the Chambre des Députés by François Dominique Arago, an astronomer, physicist, chemist, and member of the Chambre.
Arago was instrumental in arranging that the French government acquire the invention and give it to the world, in exchange for granting pensions to Daguerre and to Niépce's son Isidore.
During the summer, Arago gave a more detailed presentation to the Chambre, but it was not until Daguerre published this pamphlet that a step-by-step description became available.
seeing.nypl.org /258bt.html   (128 words)

  
 Optics 6
Fresnel was able to explain polarization using Young’s suggestion that light was a transverse vibration and his analyses of diffraction effects were convincing, but the final proof of the wave theory depended on the experimental proof that light traveled more slowly in denser media, since the corpuscular theory required the reverse.
Arago, and then Foucault and Fizeau (who rediscovered the Doppler effect), attempted to measure the relative velocities in air and water.
Poisson who was on the review committee of the Paris Académie in 1819 objected that the theory predicted a bright spot in the center of the shadow of a circular disk.
www.ee.umd.edu /~taylor/optics6.htm   (1089 words)

  
 Francois Arago --  Encyclopædia Britannica   (Site not responding. Last check: 2007-10-29)
He also devised an experiment that proved the wave theory of light and engaged with others in research that led to the discovery of the laws of light polarization.
Arago was educated in Perpignan and at the…;
More results on "Francois Arago" when you join.
www.britannica.com /eb/article-9009171   (644 words)

  
 A History of Science Volume III - Part IV   (Site not responding. Last check: 2007-10-29)
Arago at once recognized the merit of Fresnel's work, and soon became a convert to the theory.
On the contrary, a bitter feud ensued, in which Arago was opposed by the "Jupiter Olympus of the Academy," Laplace, by the only less famous Poisson, and by the younger but hardly less able Biot.
The opposition managed to delay the publication of Fresnel's papers, but Arago continued to fight with his customary enthusiasm and pertinacity, and at last, in 1823, the Academy yielded, and voted Fresnel into its ranks, thus implicitly admitting the value of his work.
www.worldwideschool.org /library/books/sci/history/AHistoryofScienceVolumeIII/chap45.html   (517 words)

  
 No. 691: Francois Arago and Watt
Arago was born on the eve of the French Revolution.
Arago's lecture is one the French Academy isn't ready for.
Arago's initials were D.F.J. This volume also includes Arago's rejoinder, "On Machinery Considered...
www.uh.edu /admin/engines/epi691.htm   (485 words)

  
 The Science Bookstore - Chronology   (Site not responding. Last check: 2007-10-29)
Arago, F. Francois Arago verifies the existence of the Poisson bright spot
Daguerre's discovery of photography announced by Francois Arago on 7 January 1839.
Full details of the discovery were published 19 August 1839, loosened somewhat by the promise of a pension of 6000 franks to Daguerre (and 4000 to Isidore Niepce).
www.thesciencebookstore.com /chron.asp?searchstring=Arago   (148 words)

  
 AllRefer.com - Dominique FranCois Arago (Physics, Biography) - Encyclopedia
Dominique FranCois Arago[dOmEnEk´ frANswA´ ArAgO´] Pronunciation Key, 1786–1853, French physicist and astronomer.
Topics that might be of interest to you:
More articles from AllRefer Reference on Dominique Francois Arago
reference.allrefer.com /encyclopedia/A/Arago-Do.html   (175 words)

  
 References for Arago   (Site not responding. Last check: 2007-10-29)
L M Dougherty and A Dollfus, F D Arago's polarimeter and his original observation of extraterrestrial polarisation in 1811 (1989).
I Howard-Duff, D F J Arago, 1786-1853, The Journal of the British Astronomical Association 97 (1986), 26-29.
P Tucci, The Arago - Faraday controversy concerning electromagnetic induction (Italian), in Science and philosophy (Milan, 1985, 796-808.
www-groups.dcs.st-and.ac.uk /~history/References/Arago.html   (131 words)

  
 Documentation On The Arago Medallions
François Arago was born in Estagel in 1786.
Après his studies at the Polytechnic School he was appointed director of studies at the Paris Observatory and became in 1843, director delegate of the longitude office and kept his post until his death in 1853.
Between 1893 and 1942, a bronze statue of Arago, built on the meridian line of the Paris Observatory, stood on the Ile de Sein Square.
www.parissweethome.com /parisrentals/art_uk.php?id=28   (564 words)

  
 The discovery of polarization (polarization.com)
Arago discovered "interference colors" by placing a sheet of mica between a glass reflector and a calcite prism.
Arago took revenge on Biot by helping his protege, Fresnel, develop the wave theory of light, as Biot was a lifetime corpuscular.
Augustin Fresnel was perhaps the biggest discovery of Arago and Fresnel was lucky that Arago was there to encourage him.
www.polarization.com /history/history.html   (1957 words)

  
 Egyptian Stars under Paris Skies
Biot and Arago were scarcely on speaking terms, Fourier’s mathematics and his heat theory were not well thought of by Biot and Laplace, and Berthollet had little sympathy for chemical atomism.
Arago was also close friends with Fourier, whose new theory of heat conduction he strongly supported.
Biot and Arago disliked one another intensely, since Arago felt, with some justification, that Biot had muscled him aside a decade before in new optical discoveries that Arago had been the first to make.
pr.caltech.edu /periodicals/EandS/articles/LXVI4/buchwald.html   (6793 words)

  
 Bryn Mawr Classical Review 2003.09.20
One individual, with a Daguerreotype would effect the labor in a very short period of time." Within a few years, Arago's vision had become reality, and by the 1850's photographers began to accompany archaeological expeditions.
In addition to its relative ease of production -- and I stress "relative," because in its early years photography was a complex and wearisome procedure -- the photograph offered what was thought to be an unprecedented combination of accuracy and objectivity.
As we know all too well, it is often the case that scholars and travelers have not been content simply to take away images from archaeological sites (or indigenous communities).
ccat.sas.upenn.edu /bmcr/2003/2003-09-20.html   (788 words)

  
 Arago   (Site not responding. Last check: 2007-10-29)
The physicist and astronomer Dominique Francois Jean Arago, was born on 26 February 1786 in Estagel, France.
Early in the Civil War, the Coast Survey schooner Arago was ordered to report to Flag Officer Samuel F. Du Pont to assist him by conducting surveys and providing him with oceanographic data of the Southern coast for guidance in blockade duty and amphibious operations.
She departed Eastport, Maine, on 15 October 1861 and proceeded to the New York Navy Yard where she received weapons of unrecorded size and number to enable her to defend herself during her perilous work.
www.history.navy.mil /danfs/a10/arago.htm   (248 words)

  
 Chronology of Electromagnetism and Classical Optics
Francois Arago discovers that some quartz crystals will continuously rotate the electric vector of light.
Simeon Poisson predicts the Poisson bright spot at the center of the shadow of a circular opaque obstacle.
Francois Arago verifies the existence of the Poisson bright spot.
www.3rd1000.com /chronology/chrono8.htm   (426 words)

  
 A History of Photography, by Robert Leggat: BAYARD, Hippolyte   (Site not responding. Last check: 2007-10-29)
His invention of photography actually preceded that of Daguerre, for on 24 June 1839 he displayed some thirty of his photographs, and thus at least goes into the record books as being the first person to hold a photographic exhibition.
Francois Arago (a friend of Daguerre and who was seeking to promote his invention) persuaded him to postpone publishing details of his work.
When Bayard eventually gave details of the process to the French Academy of Sciences on 24 February 1840, he had lost the opportunity to be regarded as the inventor of photography.
www.rleggat.com /photohistory/history/bayard.htm   (395 words)

  
 Perpignan Museum   (Site not responding. Last check: 2007-10-29)
Under the leadership of the newly appointed curator, the Museum d'Histoire Naturelle began to prosper greatly.
Due to Companyo's hard work and numerous connections (among them the well-known astronomer François Arago (15) and the Egyptian Caliph Ibrahim Pacha), Companyo was able to gather a splendid collection for the museum, up to the time of his death in 1871.
From this cultural centre, towards the end of the nineteenth century emerged savants such as the academic Charles Deperet and the archaeologist Albert Donnezan, who bequeathed to the Museum an important part of his precious palaeontological collection to be shared with the Museum of Lyon (22).
www.mediterranees.net /museum/museum_eng.html   (3915 words)

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