Edouard Branly
Edouard Branly
    Edouard Branly
     Catholic_Encyclopedia Edouard Branly
    French physicist and inventor of the coherer employed in wireless telegraphy, born at Amiens, 23 October, 1846. After receiving his early education at the Lycée of St. Quentin, his scientific studies were begun at the Lycée Henri IV at Paris, and in l865 he entered the Ecole Normale Superieure. In 1868 he became Licentiate in mathematics and physical science, and also agrégé in physical and natural science. After occupying a professor's chair at the Lycée of Bourges, he was appointed chef des travaux in 1869 and four years later he was made director of the Laboratory of Instruction in the Departrnent of physics at the Sorbonne. In the same year (1873) he won the doctorate in science with a thesis entitled "Electrostatic phenomena in Voltaic Cells". In 1876 he resigned his post at the Sorbonne to become professor of physics at the Catholic University in Paris. He then took up the study of medicine, obtaining his degree in 1882, and thereafter divided his time between the practice of medicine, especially of physiotherapy and electrotherapy, and his researches in physics at the Catholic University.
    Dr. Branly is best known by his researches concerning radio-conductors, and particularly by his so-called coherer. He began his studies in this field in 1890, being led to undertake them by observing the anomalous change in the resistance of thin metallic films when exposed to electric sparks. Platinum deposited upon glass was first employed. The effect was at first attributed to the influence of the ultraviolet light of the spark. The variations in the resistance of metals in a finely divided state were even more striking, and they were shown by Dr. Branly to be due to the action of the electrical, or Hertzain, waves of which the spark was the source. The further experiment led to the coherer, which is simply a glass or ebonite tube containing metallic filings which connect the two ends of a wire conductor entering the tube. When the tube is made part of a battery circuit, the filings ordinarily offer a very great resistance to the passage of a current. But if a spark be produced in the neighbourhood between the terminals of an induction coil, or by the discharge of a Leyden Jar, the resistance of the filings is diminished, being no longer measured in millions but in hundreds of ohms. Upon tapping the tube the filings regain their normal resistance. This simple device was employed by Lodge in his researches and formed an important part of Marconi's successful system of wireless telegraphy. In fact the coherer first made wireless telegraphy possible. It serves as receiver being placed in series with a relay actuating a Morse sounder.
    When electrical waves, sent out at a distant station according to an established code, impinge upon it, its resistence diminishes sufficiently to enable the relay to act and this in turn reproduces the signals in the sounder. A tapper automatically restores the resistance of the filings. Dr. Branly has given the name of radio-conductors to bodies which, like filings, can be made conductors or non-conductors at will. A number of other forms have since been devised, and he hirnself has found that the tripod coherer, composed of a metal disk making contact with a polished steel plate by means of three steel legs, is more sensitive and uniform in its action than the tube coherer. He has also applied his radio-conductors to "telemechanics without wires", i. e. to the production of divers mechanical effects at a distance by means of electrical waves. Among Dr. Branly's other researches have been those relating to the effect of ultra violet light upon positively and negatively charged bodies (1890-93), electrical radio-conductivity of gases (1894), etc. It may be noted germ of the "antennae", employed particularly in long distance telegraphy, may be found in his papers published in 1891.
    Dr. Branly became Commander of the Order of St. Gregory the Great in 1899 and was nominated Chevalier of the Legion of Honour in 1900 for "having discovered the principle of wireless telegraphy." He received the grand prix at the Paris Exposition, 1900, for his radio-conductors, and the prix Osiris, in 1903, from the Syndicate of the Press. He was also made a titular member of the Pontifical Academy dei Nuovi Lincei. Besides his papers published chiefly in the "Comptes Rendus", Dr. Branly is the author of a "Cours élémentaire de physique" (5th ed., 1905); and "Traite élémentaire de physique" (3d ed., 1906). For various types of coherer and other apparatus employed in wireless telegraphy, cf. Collins, "Wireless Telegraphy" (New York; 1905).
    H.M. BROCK
    Transcribed by Joseph P. Thomas

The Catholic Encyclopedia, Volume VIII. — New York: Robert Appleton Company. . 1910.


Catholic encyclopedia.

Look at other dictionaries:

  • Edouard Branly — Édouard Branly Pour les articles homonymes, voir Branly. Édouard Branly Naissance …   Wikipédia en Français

  • Édouard Branly — Édouard Eugène Désiré Branly (October 23, 1844 March 24, 1940) was a French inventor and physicist. He was the physics professor at the Catholic University of Paris. He is primarily known for his early involvement in wireless telegraphy and his… …   Wikipedia

  • Édouard Branly — Édouard Eugène Désiré Branly (23 de octubre de 1844 – 24 de marzo de 1940) fue un físico, inventor y profesor francés del Institut Catholique de Paris. Es especialmente conocido por sus aportaciones pioneras a la telegrafía sin hilos (derivadas… …   Wikipedia Español

  • Edouard Branly — Édouard Branly Édouard Branly (* 23. Oktober 1844 in Amiens; † 24. März 1940 in Paris) war ein französischer Physiker und Pionier in der Anfangszeit der Funktechnik. Leben und Wirken Édouard Branly studierte an der Unive …   Deutsch Wikipedia

  • Édouard Branly — (* 23. Oktober 1844 in Amiens; † 24. März 1940 in Paris) war ein französischer Physiker und Pionier in der Anfangszeit der Funktechnik. Leben und Wirken …   Deutsch Wikipedia

  • Édouard Branly — Pour les articles homonymes, voir Branly. Édouard Branly Naissance …   Wikipédia en Français

  • Musée Edouard Branly — Plaque at the Musée Edouard Branly on rue d Assas in Paris The Musée Edouard Branly is a museum dedicated to the work of radio pioneer Edouard Branly (1844 1940). It is located in the 6th arrondissement at the Institut Catholique de Paris ISEP,… …   Wikipedia

  • Lycee Edouard-Branly (Nogent-sur-Marne) — Lycée Édouard Branly (Nogent sur Marne) Pour les articles homonymes, voir Lycée Édouard Branly. Lycée Édouard Branly …   Wikipédia en Français

  • Lycée Edouard-Branly (Nogent sur Marne) — Lycée Édouard Branly (Nogent sur Marne) Pour les articles homonymes, voir Lycée Édouard Branly. Lycée Édouard Branly …   Wikipédia en Français

  • Lycée Edouard Branly (Nogent sur Marne — Lycée Édouard Branly (Nogent sur Marne) Pour les articles homonymes, voir Lycée Édouard Branly. Lycée Édouard Branly …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”