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Milestones:Discovery of Radioconduction by Edouard Branly, 1890

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<p>''Discovery of Radioconduction by Edouard Branly, 1890''</p>
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== Discovery of Radioconduction by Edouard Branly, 1890 ==
  
<p>''In this building, Edouard Branly discovered radioconduction, now called the Branly Effect. On 24 November 1890, he observed that an electromagnetic wave changes the ability of metal filings to conduct electricity. Branly used his discovery to make a very sensitive detector called a coherer, improved versions of which became the first practical wireless signal receivers.<br>''</p>
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<p>''In this building, Edouard Branly discovered radioconduction, now called the Branly Effect. On 24 November 1890, he observed that an electromagnetic wave changes the ability of metal filings to conduct electricity. Branly used his discovery to make a very sensitive detector called a coherer, improved versions of which became the first practical wireless signal receivers.''</p>
  
<p>&nbsp;The discovery of the radioconduction is a phenomenon which revolutionized the means of communication. It is at the origin of the development of the TSF (Télégraphie Sans Fil, or wireless telegraphy). As a member of the French Academy of Sciences (it gains vis-a-vis Marie Curie), Branly received international recognition.&nbsp;No more than about&nbsp;fifteen years separate the first wireless transmission&nbsp;across a few meters (1890)&nbsp;from the&nbsp;first transatlantic communication (Marconi, December 1901). Radioconduction (Branly’s effect) is still the subject of research, it was partially interpreted by Bernard Castaing (member of the Academy of Science of Paris) in 2006.</p>
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<p>The plaque may be viewed at 21 rue d'Assas, 75006, Paris,&nbsp;France&nbsp;on the wall of the building of the “Institut Catholique de Paris” (a renowned catholic university founded by Ozanam and Cauchy)), which housed, in Particular, ISEP, a School of Engineering linked with Stanford University. In this very place, Edouard Branly discovered the radioconduction on November 24th 1890. </p>
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<p>The discovery of the radioconduction is a phenomenon which revolutionized the means of communication. It is at the origin of the development of the TSF (Télégraphie Sans Fil, or wireless telegraphy). As a member of the French Academy of Sciences (it gains vis-a-vis Marie Curie), Branly received international recognition.&nbsp;No more than about&nbsp;fifteen years separate the first wireless transmission&nbsp;across a few meters (1890)&nbsp;from the&nbsp;first transatlantic communication (Marconi, December 1901). Radioconduction (Branly’s effect) is still the subject of research, it was partially interpreted by Bernard Castaing (member of the Academy of Science of Paris) in 2006.</p>
  
 
<p>The “filings tube” (or coherer) was the first widely used detector for radio communication. The operation of the coherer is based upon the large resistance offered to the passage of electric current by loose metal filings, which decreases under the influence of radio frequency. The coherer became the basis for radio reception, and remained in widespread use for about ten years. It was used by, amongst others, Guglielmo Marconi, in his early experiments. Oliver Lodge adds a "trembler" which periodically dislodged clumped filings, thus restoring the device's sensitivity. The “coheror” was used not only during the first phase of development of the wireless telegraphy, but it was also used by Christian Hülsmeyer as a receiver of his Telemobiloskop, the first radar (1904).</p>
 
<p>The “filings tube” (or coherer) was the first widely used detector for radio communication. The operation of the coherer is based upon the large resistance offered to the passage of electric current by loose metal filings, which decreases under the influence of radio frequency. The coherer became the basis for radio reception, and remained in widespread use for about ten years. It was used by, amongst others, Guglielmo Marconi, in his early experiments. Oliver Lodge adds a "trembler" which periodically dislodged clumped filings, thus restoring the device's sensitivity. The “coheror” was used not only during the first phase of development of the wireless telegraphy, but it was also used by Christian Hülsmeyer as a receiver of his Telemobiloskop, the first radar (1904).</p>
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<p>One of the most famous street in Paris is Quai Edouard Branly (a road that runs alongside the River Seine along the Eiffel Tower. It is the name of this road, not of Branly himself, that led to the naming of the Musée du quai Branly). There are a lot of streets “Edouard Branly” in France</p>
 
<p>One of the most famous street in Paris is Quai Edouard Branly (a road that runs alongside the River Seine along the Eiffel Tower. It is the name of this road, not of Branly himself, that led to the naming of the Musée du quai Branly). There are a lot of streets “Edouard Branly” in France</p>
  
<p>A museum is dedicated to his achievements : Musée Branly, see : http://www.museebranly.isep.fr/ </p>
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<p>A museum is dedicated to his achievements&nbsp;: Musée Branly, see&nbsp;: http://www.museebranly.isep.fr/ </p>
  
 
<p>There is a memorial dedicated to Edouard Branly in the Jardin du Luxembourg (at ~ 500 m of the Institut Catholique de Paris where the milestone&nbsp;plaque is fixed)</p>
 
<p>There is a memorial dedicated to Edouard Branly in the Jardin du Luxembourg (at ~ 500 m of the Institut Catholique de Paris where the milestone&nbsp;plaque is fixed)</p>
  
<p>A specific association exists since 1978 : Association des amis d’Edouard Branly (web site will open end of May 2008)</p>
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<p>A specific association exists since 1978&nbsp;: Association des amis d’Edouard Branly (web site will open end of May 2008)</p>
  
 
<p>Prix Branly (Branly’s Prize) is given each year on November 24th since 1990 under the auspice of the “Association des amis d’Edouard Branly”</p>
 
<p>Prix Branly (Branly’s Prize) is given each year on November 24th since 1990 under the auspice of the “Association des amis d’Edouard Branly”</p>
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<p></p>
 
<p></p>
  
<p>'''Some reference book on this subject'''</p>
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== Some reference book on this subject ==
  
<p>• Edouard Branly et la T.S.F, Gabriel Pelletier et Jean Quinet, Ed. Seghers, collection "Savants du monde entier" (1962) [Gabriel Pelletier was the assistant of Edouard Branly]</p>
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*Edouard Branly et la T.S.F, Gabriel Pelletier et Jean Quinet, Ed. Seghers, collection "Savants du monde entier" (1962) [Gabriel Pelletier was the assistant of Edouard Branly]  
 
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*Branly au temps des ondes et des limailles, Philippe Monod-Broca (afterword of Jean Cazenobe), Ed. Belin, collection "Un savant, une époque" (1999)  
<p>• Branly au temps des ondes et des limailles, Philippe Monod-Broca (afterword of Jean Cazenobe), Ed. Belin, collection "Un savant, une époque" (1999)</p>
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*Musée Branly, appareils et matériaux d’expériences, Association des amis d’Edouard Branly, catalogue of the Museum, supported by Richard Loundsbery Fundation.  
 
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*Comment Branly a découvert la radio, Jean-Claude Boudenot (Nominator of the Milestone) Ed. EdP Sciences (2005)
<p>• Musée Branly, appareils et matériaux d’expériences, Association des amis d’Edouard Branly, catalogue of the Museum, supported by Richard Loundsbery Fundation.</p>
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<p>• Comment Branly a découvert la radio, Jean-Claude Boudenot (Nominator of the Milestone) Ed. EdP Sciences (2005)</p>
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<p>See also, in English&nbsp;:</p>
 
<p>See also, in English&nbsp;:</p>
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<p>47/ Thermomètre à base métallique, 23 décembre 1935.<br></p>
 
<p>47/ Thermomètre à base métallique, 23 décembre 1935.<br></p>
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<div class="header"><span class="head1">INNOVATION</span><span class="head2">  MAP</span></div>
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<p><!-- Radioconduction --> <googlemap version="0.9" lat="48.849016" lon="2.32968" zoom="10" width="300" height="250" controls="small">
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48.849016, 2.32968,
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Discovery of Radioconduction by Edouard Branly, 1890
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Institut Catholique de Paris, Paris, France
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</googlemap> </p>
  
<p></p>
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[[Category:Fields, waves & electromagnetics|Radioconduction]] [[Category:Magnetic devices|Radioconduction]]
 
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<p>[[Category:Fields,_waves_&_electromagnetics|{{PAGENAME}}]] [[Category:Magnetic_devices|{{PAGENAME}}]]</p>
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Latest revision as of 15:01, 4 April 2012

Discovery of Radioconduction by Edouard Branly, 1890

In this building, Edouard Branly discovered radioconduction, now called the Branly Effect. On 24 November 1890, he observed that an electromagnetic wave changes the ability of metal filings to conduct electricity. Branly used his discovery to make a very sensitive detector called a coherer, improved versions of which became the first practical wireless signal receivers.

The plaque may be viewed at 21 rue d'Assas, 75006, Paris, France on the wall of the building of the “Institut Catholique de Paris” (a renowned catholic university founded by Ozanam and Cauchy)), which housed, in Particular, ISEP, a School of Engineering linked with Stanford University. In this very place, Edouard Branly discovered the radioconduction on November 24th 1890.

The discovery of the radioconduction is a phenomenon which revolutionized the means of communication. It is at the origin of the development of the TSF (Télégraphie Sans Fil, or wireless telegraphy). As a member of the French Academy of Sciences (it gains vis-a-vis Marie Curie), Branly received international recognition. No more than about fifteen years separate the first wireless transmission across a few meters (1890) from the first transatlantic communication (Marconi, December 1901). Radioconduction (Branly’s effect) is still the subject of research, it was partially interpreted by Bernard Castaing (member of the Academy of Science of Paris) in 2006.

The “filings tube” (or coherer) was the first widely used detector for radio communication. The operation of the coherer is based upon the large resistance offered to the passage of electric current by loose metal filings, which decreases under the influence of radio frequency. The coherer became the basis for radio reception, and remained in widespread use for about ten years. It was used by, amongst others, Guglielmo Marconi, in his early experiments. Oliver Lodge adds a "trembler" which periodically dislodged clumped filings, thus restoring the device's sensitivity. The “coheror” was used not only during the first phase of development of the wireless telegraphy, but it was also used by Christian Hülsmeyer as a receiver of his Telemobiloskop, the first radar (1904).

The discovery of electromagnetic waves had been made by Heinrich Hertz in 1888, but the “detector” he used (a simple loop) was very ineffective, while a “coheror” was able to detect even a faint signal. Furthermore the “coheror” was able to be directly linked to a Morse’s system, and though it was able to be used in a wireless communication. Edouard Branly is one of the pioneer of wireless transmission along with Heinrich Hertz, Oliver Lodge and Guglielmo Marconi.

Heinrich Rudolf Hertz (1857-1894), a professor of physics at Karlsruhe Polytechnic, was the first to broadcast and receive radio waves in the laboratory. Between 1885 and 1889, he used spark discharges to produce electromagnetic waves. His receiver was a loop of wire with a small gap across which a small spark could be observed when the radiator discharged. Hertz died suddenly when he was thirty six, perhaps never realizing that transmission and reception over long distances was possible.

Edouard Eugène Désiré Branly (1844-1940) is at the origin of wireless telegraphy. In 1890, Branly, a professor of Physics at the Catholic University of Paris, discovered that when exposed to even a distant spark transmission field, loose zinc and silver filings would “cohere” and provide a path of increased conductivity that could be used to detect the presence of the transmission. The "coherer" took radio transmission out of the laboratory and made communication over long distances possible.

Oliver Joseph Lodge (1851-1940) held the chair in Physics at the University College in Liverpool when he demonstrated a practical form of the Branly coherer in 1894. Lodge added a device that shook the filings loose between spark receptions. It became a standard device in early wireless telegraphy. Lodge also obtained the first patents for the use of tuned circuits to adjust the frequency of receivers and transmitters.

Guglielmo Marconi (1874-1937) In 1896, at age twenty-two, he patented a successful system of radio telegraphy. In the following years he introduced a notable series of inventions and ingenious redesigns of transmitting and receiving system components. In 1901 Marconi succeeded in receiving signals transmitted across the Atlantic Ocean. Marconi's Wireless Telegraphy Company soon established a net of coast stations in Britain for ship-to-shore communication. These were taken over by the British General Post Office in 1910, but for more than a decade the Marconi Company enjoyed a monopoly on maritime radio equipment sales by virtue of an agreement with Lloyds of London to only insure ships that used their equipment. In 1909 Marconi received the Nobel Prize for Physics.

During the first trans channel wireless transmission, Marconi sent the following telegram to Branly : “Mr. Marconi sends to Mr. Branly his respectful compliments for the wireless telegraphy through the English Channel. This beautiful result being due partly to remarkable work of Mr. Branly.”

One of the most famous street in Paris is Quai Edouard Branly (a road that runs alongside the River Seine along the Eiffel Tower. It is the name of this road, not of Branly himself, that led to the naming of the Musée du quai Branly). There are a lot of streets “Edouard Branly” in France

A museum is dedicated to his achievements : Musée Branly, see : http://www.museebranly.isep.fr/

There is a memorial dedicated to Edouard Branly in the Jardin du Luxembourg (at ~ 500 m of the Institut Catholique de Paris where the milestone plaque is fixed)

A specific association exists since 1978 : Association des amis d’Edouard Branly (web site will open end of May 2008)

Prix Branly (Branly’s Prize) is given each year on November 24th since 1990 under the auspice of the “Association des amis d’Edouard Branly”

A school of Engineering was name after him (“Ecole Branly”, now Institut Supérieur d’Electronique de Paris, ISEP). Several “Lycée Branly” exist in France.

Some reference book on this subject

  • Edouard Branly et la T.S.F, Gabriel Pelletier et Jean Quinet, Ed. Seghers, collection "Savants du monde entier" (1962) [Gabriel Pelletier was the assistant of Edouard Branly]
  • Branly au temps des ondes et des limailles, Philippe Monod-Broca (afterword of Jean Cazenobe), Ed. Belin, collection "Un savant, une époque" (1999)
  • Musée Branly, appareils et matériaux d’expériences, Association des amis d’Edouard Branly, catalogue of the Museum, supported by Richard Loundsbery Fundation.
  • Comment Branly a découvert la radio, Jean-Claude Boudenot (Nominator of the Milestone) Ed. EdP Sciences (2005)

See also, in English :

http://en.wikipedia.org/wiki/Edouard_Branly

http://en.wikipedia.org/wiki/History_of_radio

3/ List of Edouard Branly’s communication at French Academy of Science

1/ Recherches sur le rayonnement solaire (avec P. Desains), 29 novembre 1869

2/ Mesures de la polarisation dans l'élément voltaïque, 19 février 1872

3/ Mesure de l'intensité des courants au moyen de l'électromètre, 12 août 1872

4/ Evaluation en unités mécaniques de la quantité d'électricité que produit un élément de pile, 15 décembre 1873

5/ Sur l'emploi du gaz d'éclairage comme source constante dans les expériences de rayonnement, 21 mars 1887

6/ Nouveau mode d'emploi du thermomultiplicateur, 12 avril 1887

7/ Déperdition des deux électricités dans l'éclairement par des radiation très réfrangibles, 8 avril 1890

8/ Courants photo-électriques entre les deux plateaux d'un condensateur, 28 avril 1890

9/ Variations de conductibilité sous diverses influences électriques, 24 novembre 1890

10/ Variations de conductibilité des substances isolantes, 12 janvier 1891

11/ Déperdition des deux électricités par les rayons très réfrangibles, 11 janvier 1892

12/ Nouvelle conductibilité unipolaire des gaz, 4 avril 1892

13/ Sur la conductibilité d'un gaz compris entre un métal froid et un corps incandescent, 27 juin 1892

14/ Sur la déperdition de l'électricité à la lumière diffuse et à l'obscurité, 10 avril 1893

15/ Résistance des lames métalliques minces, 3 février 1894

16/ Sur la conductibilité des substances conductrices discontinues, 12 février 1894

17/ Déperdition électrique par l'illumination de corps médiocrement conducteurs, 16 avril 1895

18/ Résistance électrique au contact de deux métaux, 22 avril 1895

19/ Résistance des lames métalliques minces, 3 février 1896

20/ Sur la propriété de décharger les corps électrisés, produite dans les gaz par les corps incandescents et par les étincelles électriques, 26 octobre 1896

21/ Sur la conductibilité électrique des substances conductrices discontinues, à propos de la télégraphie sans fil, 6 décembre 1897

22/ Conductibilité des radioconducteurs ou conductibilité électrique discontinue. Assimilation à la conductibilité nerveuse, 27 décembre 1897

23/ Une enveloppe métallique ne se laisse pas traverser par les oscillations hertziennes, 4 juillet 1898

24/ Télégraphie sans fil et collisions en mer, 18 juillet 1898

25/ Résistance électrique au contact de deux disques d'un même métal, 25 juillet 1898

26/ Radioconducteurs à limailles d'or et de platine, 26 décembre 1898

27/ Sur l'absorption des ondes hertziennes par les corps non métalliques (avec G. Le Bon), 4 avril 1899

28/ Radioconducteurs à billes métalliques, 1er mai 1899

29/ Transmission des ondes hertziennes à travers les liquides, 30 octobre 1899

30/ Accroissements de résistance des radioconducteurs, 17 avril 1900

31/ Sur l'électrolyse des tissus animaux, 3 juin 1901

32/ Radioconducteurs à contact unique, 10 février 1902

33/ Récepteur de télégraphie sans fil, 26 mai 1902

34/ Distribution et contrôle d'actions produites à distance par les ondes électriques, 20 mars 1905

35/ Appareil de Télémécanique sans fil de ligne, 26 juin 1905

36/ Appareil de sécurité contre les étincelles accidentelles dans les effets de télémécanique sans fil, 22 octobre 1906

37/ Etablissement, entre un poste transmetteur et un des postes récepteurs d'une installation de télémécanique sans fil, d'une correspondance exclusive, indépendante de la syntonisation, 5 novembre 1906

38/ Accroissement de sensibilité des révélateurs électrolytiques sous diverses influences, 9 mars 1908

39/ Remarques à propos de la note de M. Tissot Sur l'emploi de détecteurs sensibles d'oscillations électriques basés sur les phénomènes thermo-électriques présentée à la séance du 6 juillet – Radioconducteurs à pointes de tellure et tellurures, 13 juillet et 3 août 1908

40/ Appareil de sécurité contre les étincelles perturbatrices ininterrompues, en télémécanique sans fil, 20 juillet 1908

41/ Conductibilité intermittente des minces couches diélectriques, 11 novembre 1912

42/ Conductibilité intermittente des lames minces diélectriques, 14 décembre 1914

43/ Conductibilité d'une mince couche d'air entre deux surfaces métalliques, 20 décembre 1915

44/ Conductibilité de l'air et du mica, 26 décembre 1916

45/ Conductibilité électrique du mica, 8 octobre 1917

46/ Influences électrométalliques exercées à travers des feuilles isolantes de très petite épaisseur, 22 octobre 1917

47/ Thermomètre à base métallique, 23 décembre 1935.

INNOVATION MAP