Bucherer, Alfred Heinrich

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Bucherer, Alfred Heinrich

(b. Cologne, Germany, 9 July 1863; d. Bonn, Germany, 16 April 1927)

Physics.

Alfred Bucherer’s father, Heinrich Bucherer, was the owner of a chemical factory in Cologne. His mother was English. Besides his interests in chemistry and technology, the father was an art lover; his wife was a devotee of music and languages, and it was in such surroundings that Alfred Bucherer was raised. He exhibited unusual talents, not only in mathematics and the physical sciences but in philology as well. He was a man who was equally at home in the worlds of physics, chemistry, technology, and philology.

After spending the year 1884 studying at the Technische Hochschule at Hannover, Bucherer went to the United States, to Johns Hopkins, where the continued his technical studies and at the same time studied philology. At Hopkins he came under the influence of the chemist Ira Remsen. While studying under Remsen he became engrossed in thermodynamics, and as a direct consequence of this work, he obtained a patent for the separation of aluminum from its sulfide. He returned to the United States in 1893 to spend a year studying at Cornell. His intimate knowledge of vector analysis stemmed from his work during this period.

Bucherer completed his formal education in 1895 under Braun at Strasbourg. His topic, the effects of magnetic fields on the electromotive force, was another direct outcome of his work with Remsen. Bucherer continued traveling and studying for the next three years, spending part of that time with Ostwald at Leipzig.

He became Privatdozent at Bonn in 1899 and was to remain connected with Bonn in one way or another until his death. In 1912 he became professor of physics and in 1923 honorary professor of physics. He maintained an active laboratory in the university until his death.

With his arrival at Bonn, Bucherer’s academic interests became modified. He discontinued his work in physical chemistry and became more and more involved in problems in physics. Besides his patent for the separation of aluminum from its sulfide, a second patent, which Bucherer had obtained in, was for the transmission of pictures by wireless. It seems that it was in the interest of making this patent more fruitful that Bucherer turned to the questions of the nature of the electron and the effects of the motion of bodies on electromagnetic phenomena.

In 1904 in a monograph on the theory of electrons (Mathematische Einführung in die Elektronentheorie) Bucherer produced his own theory of the moving electron, which rivaled the theories of Max Abraham and H. A. Lorentz. Whereas Abraham’s theory was predicated on a rigid electron and Lorent’s theory was predicated on an electron that contracted in the direction of motion, Bucherer’s theory assumed an electron that contracted, but in such a way as to maintain a constant volume. According to Bucherer, the contraction was such that the moving electron became an ellipse with axes given by as1\3, as-1/6, as-1/6 where a is the radius of the spherical resting electron and s is given by (1—v2/c2), v being the velocity of the electron and c being the velocity of light. This led to a prediction for the transverse mass of the moving electron which was midway between the predictions of Abraham and Lorentz and Einstein, Einstein’s special theory of relativity making predictions for the transverse mass identical with those of Lorentz.

This result was within the range of experimental values for the mass of the moving electron obtained by Wilhelm Kaufmann in 1906. Kaufmann’s data, however, which he held to be in favor of the Abraham theory, were suspect. In order to settle the question, Bucherer decided to undertake his own measurements of the specific mass of the electron. This he did in 1908. In a remarkable and abrupt turnabout, he concluded that the data he obtained supported not his own theory but the theory Einstein.

Bucherer’ lively and polemical style was responsible for his often getting into arguments in the literature. This was especially true of his work on the mass of the moving electron. While he ended up supporting Einstein in this case, he was never completely happy with the relativistic formulation of physics.

BIBLIOGRAPHY

I. Original Works. Die Wirkung des Magnestismus auf die elektromotorische Kraft, diss. (Leipzig, 1896); Mathematische Einführung in die Elektronentheorie (Leipzig, 1904); “Das deformiert Elecktron und die Theorie des Elektromagnetismus,” in Physikalsiche Zeitschrift, 6 (1905), 833–834; “On a New Principle of Relativity in Electromagnetism,” in Philosophical Magazine, 13 (1907), 413–429; “Messungen an Becquerelstrahlen. Die experimentelle Bestätigung der Lorentz-Einsteinschen Theorid,” in Deutsche Physikalische Gesellschaft, Verhandlungen, 10 (1908), 688–699; “On the Priniciple of Relativity and the Electromagnetic Mass of the Electron, A Reply to Mr. Cunningham,” in Philosophical Magazine, 15 (1908), 316–318; “On the Principle of Relativity. A Reply to Mr. Cunningham,” ibid., 16 (1908), 939–940; “Antwort auf die Kritik von Besterlmeyer bezüglich meiner expermentelle Bestätigng des Relativitätsprinzips,” in Annalen der Physik, 30 (1909), 974–986; “Gravitation und Quanten- theorie I,” ibid., 68 (1922), 1–10; “Gravitation und Quatentheories II,” ibid., 546–551.

II. Secondary Literature, Max Abraham, Theorie der Elekritzität, 2 vols. (Leipzig, 1904–1905); Stanley Goldberg, “Early, Response to Einstein’s Special Theory of Relativity,” unpublished doctoral thesis (Harvard University, 1968), chs. 1, 2; E.T. Whittaker, A History of the Theories of Aether and Electricity, 2 vols. (New York, 1960).

Stanley Goldberg