Paul Janet (physicist)

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Paul André-Marie Janet (born January 10, 1863 in Paris , † February 21, 1937 in Malakoff ) was a French physicist .

Life

He was born in Paris to Paul Janet , a professor of philosophy at the Sorbonne . At the age of nine he became a student at the Lycée Louis-le-Grand in Paris, where his father had taught logic for some time .

The visit to the International Electricity Exhibition in Paris in 1881 fascinated him so much that he decided against the tradition of his family to study science. From 1883 he attended the École normal supérieure and attended the lectures of Jules Violle until he received his university degree in physics in 1886.

At the age of 23 he worked at the science faculty of the University of Grenoble , to which Jules Violle had recommended him for his dissertation. In 1887 he then wrote his thesis entitled Transverse Magnetization of a Conductor , in which he described the basics of electromagnetic recording of sound and speech. Regardless of this, Oberlin Smith had already submitted a comparable idea in the United States in 1878 as a patent caveat , the preliminary application for a later patent application. Smith first brought his idea to the public with his letter to the editor Some possible forms of phonograph , which was published in the magazine The Electrical World on September 29, 1888 , and it was the Danish inventor Valdemar Poulsen who first succeeded with his telegraphone to construct a functioning device.

In 1893 he took over the professorship at his faculty and set up his own institute for electrical engineering with an experimental laboratory that was very advanced for the time, in successful cooperation with industry in the vicinity. He was so convinced of the teaching benefits of such an exchange of knowledge that he wrote several books on applied electricity. He was succeeded by Joseph Pionchon in 1994. Paul Janet moved to Paris to the École normal supérieure and took over the management of the Laboratoire central d'électricité (German: Central Laboratory for Electricity).

From November 1894 he taught physics at the natural science faculty in Paris, worked from 1895 to 1897 at Georges Urbain's chair , became assistant professor around 1900 and on November 1, 1901 finally full professor for the field of electrical engineering. He held this chair until June 25, 1922. On December 8, 1919, he was elected as a member of the Paris Académie des Sciences , from which he did not retire until 1934 for reasons of age. Also in 1934 he was accepted into the American Academy of Arts and Sciences .

In his honor, a lecture hall at the École supérieure d'électricité (Supélec) now bears his name.

Works

With his work on the transversal magnetizability of a conductor , he suggested the possibility of magnetic sound recording on steel wire. For this purpose, he had recorded field line images during experiments with a single-winding coil on a paper tape covered with iron powder. The unwinding coil had the shape of a metal tube with a gap, the effect of which he was able to calculate well and which is to be regarded as the simplified form of the modern recording and playback head.

  • Faculté des sciences de Grenoble. Leçon d'ouverture du cours de physique. La Physique mathématique et la physique expérimentale , Paris, bureau des deux revues, 1887
  • Étude théorique et expérimentale sur l'aimantation transversale des conducteurs magnétiques , Gauthier-Villars et fils, 1890
  • Premiers principes d'électricité industrial. Piles, accumulateurs, dynamos, transformateurs , Gauthier-Villars et fils, 1893
  • Leçons d'Electrotechnique générale professées à l'École supérieure d'électricité , Paris, Gauthier-Villars, 1923 (lire en ligne)
  • (Preface to) P. Roberjot: Cours élémentaire d'électricité industrial , Dunod, 1924
  • (Preface to) A. Defretin: Cours d'électricité industrial, à l'usage des élèves-ingénieurs , libr. scientifique Hermann et Cie, coll. «Institut industriel du Nord», 1929
  • (together with) Paul Painlevé: 1863–1933 , Paris, SGIE, 1934

literature

  • Dugald C. Jackson: Proceedings of the American Academy of Arts and Sciences , Vol. 72, No. 10, American Academy of Arts & Sciences 1938, pp. 363–365
    ( limited preview at: jstor.org)

Individual evidence

  1. ↑ Elizabeth Antebi: The electronics era , Springer Basel 1982, ISBN 3-0348-6741-7 , S. 161
    ( limited preview in Google Book Search)
  2. ^ List of members since 1666: letter J. Académie des sciences, accessed on November 30, 2019 (French).
  3. ^ Walter Bruch: 100 years of sound and image storage . In: Funkschau , year 1982, issue no.17, article no.42, quoted at: Magnetbandmuseum.info , accessed on November 11, 2015
personal data
SURNAME Janet, Paul
ALTERNATIVE NAMES Janet, Paul André-Marie (full name)
BRIEF DESCRIPTION French physicist
DATE OF BIRTH January 10, 1863
PLACE OF BIRTH Paris
DATE OF DEATH February 21, 1937
Place of death Malakoff