Ein bisher unveröffentlichter Brief von Rudolf Kohlrausch and Andreas v. Ettingshausen von 1854, das Kohlrausch-Weber-Experiment von 1854/55 und die Lichtgeschwindigkeit in Wilhelm Webers Elektrodynamik

Abstract

The reason for this letter was a belated delivery of the sinuselectrometer to the Austrian mathematician and physicist A.v. Ettingshausen in Vienna. The instrument was designed by R. Kohlrausch and made by the mechanic of the university in Marburg. By means of ths instrument the relations of charges could be measured. At the end of the letter Kohlrausch reported on the experiment made together with Wilhelm Weber for the determination of the relation between the absolute electrostatic and electromagnetic measured charges. The result was the velocity of light, but not perceived as such by Weber and Kohlrausch. In 1857 G. R. Kirchhoff was the first to define the connection between C w and C l ( $$c_w = \sqrt 2 \cdot c_L $$ ). for a better understanding the dimensions of the Triple-Systems (Dreiersysteme) are used in the article. A. v. Ettingshausen was in close contact with the university of Gottingen and published the results of C. F. Gauss' and Weber's research work in the Danubian monarchy at an early time. When in 1857 Kirchhoff presented his two important works on the undulatory motion of electricity in conductors to J. C. Poggendorff, the editor of the Annals of Physics and Chemistry—Kirchhoff's works contain a preliminary form of the telegraph-equations—it became apparent that W. Weber and R. Kohlrausch had almost brought about a similar work and had come to the same result as Kirchhoff. On account of Kohlrausch's death in 1858 W. Weber was forced to finish the work by himself and published it only 1864 entitled “Uber elektrische Schwingungen”. 1861 Maxwell at once discerned the velocity of light in the result and was now able to develop his elctromagnetic theory of light.