Bernard Brunhes

Bernard Brunhes

Bernard Brunhes (* 1867 in Toulouse ; † 1910 in Clermont-Ferrand ) was a French geophysicist , a pioneer of paleomagnetism and director of the observatory on the Puy de Dôme from 1900 to 1909. He discovered in 1906 while studying the magnetization of volcanic rock samples, that the earth's magnetic field reversed its polarity in the course of earth's history.

Brunhes studied at the École normal supérieure with a degree ( Agrégé ) in physics. He was from 1893 (after he had obtained his doctorate in 1893 on internal reflection in crystals) Maitre de Conference at the University of Lille and taught physics and electrical engineering at the Institut industriel du Nord ( École Centrale de Lille ) from 1893 to 1895 . He was then a professor at the Universities of Dijon and Clermont-Ferrand . In November 1900 he became director of the observatory on the Puy de Dôme in the Massif Central , about 15 km from Clermont-Ferrand , which is located on a former volcano. He stayed there until his death.

In 1905 he discovered that the rocks of a lava flow near Pont Farin (then Pontfarein) 20 km west of Saint-Flour (Cantal) had a magnetic polarity (of the enclosed iron minerals) almost opposite to today's geomagnetic field. He concluded that the polarity of the earth's magnetic field was reversed, an idea that only became generally accepted in the 1950s (with paleomagnetic research by PMS Blackett , Keith Runcorn and others).

With his brother, the geographer Jean Brunhes (1869–1930), he was a member of the Société de la Haute-Auvergne, a regional scientific society, since it was founded in 1898.

With J. Blondin he edited Henri Poincaré's lectures on electricity and optics in 1890 . He himself published lectures on electricity and in the book La dégradation de l'energie, among other things, on the progressive destruction of forests and soil erosion through the private use of communal areas in France.

Fonts

• Cours élémentaire d'électricité Lois expérimentales et principes généraux. Introduction à l'électrotechnique. Leçons professées à l'Institut industriel du Nord de la France, Gauthier-Villars, 1895
• Sur le principe d'Huygens et sur quelques conséquences du théorème de Kirchhoff, Lille, au siège des Facultés, 1895
• La dégradation de l'énergie, Flammarion, 1909, reprinted 1991
• Recherches sur la direction d'aimantation des roches volcaniques, Journal of Physique, Series 4, Volume 5, 1906, pp. 705-724.

literature

• J. Didier, A. Roche: Life and work of a physicist: Bernard Brunhes (1867-1910), pioneer of earth magnetism . In: Comptes Rendus de l'Academie des Sciences Series IIA Earth and Planetary Science 328, 1999, pp. 141-152

Individual evidence

1. ↑ Bernard Brunhes on the website of the Observatoire de Physique du Globe de Clermont-Fd., History section . (French) (accessed March 9, 2013)
2. ↑ List of directors of the Puy de Dome observatory on its homepage (French) (accessed on March 9, 2013)
3. ↑ Laj, Kissel The Bernard Brunhes Site Revisited , EGS XXVII General Assembly, Nice, April 2002 bibcode : 2002EGSGA..27.5303L .