‎"FRANCK, J. und G. HERTZ. - PROVING THE QUANTIZED MODEL OF THE BOHR ATOM AND PLANCK'S QUANTUM THEORY.‎
‎Über Zusammenstösse zwischen Elektronen und den Molekülen des Quecksilberdampfes und die Ionisierungsspannung desselben. (+) Über die Erregung der Quecksilberresonanzlinie 253,6 (u,u) durch Elektronenstösse.‎

‎Braunschweig, Friedr. Vieweg & Sohn, 1914. Lex8vo. Contemp hcloth, gilt spine. Lower spine end a bit frayed, otherwise very fine. In: ""Verhandlungen der deutschen Physikalischen Gesellschaft im Jahre 1914"", 16. Jahrgang. IX,1072 pp. Franck & Hertz' papers: pp. 457-467 a. 512-517, textillustr. Fine and clean.‎

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‎First apperance of the famous Franck-Hertz Experiment which is considered as a new and independent support, not only of Planck's quantum theory and Einstein's light-quantum hypothesis but also of Bohr's theory of the atom with stationary states of discrete energies.Franck and Hertz were awarded the Nobel Prize in Physics in 1925 for this work and Franck concluded his Nobel lecture with the words ""We know only to well that we owe the wide recognition that our work received to contact with the great concepts and ideas of M. Planck and in particular Niels Bohr.""""In their famous experiments, Franck and Hertz' showed that electrons could impart energy to a mercury atom only if they had a kinetic energy exceeding 4.9 ev., and that exactly this quantum of energy was taken up by the mercury atom, causing it to emit light of the resonance line Å 2537. It was the first direct proof of the quantized nature of the energy transfer and of the connection of the quantum DeltaE of energy with the frequency p = DeltaE/h of the light emitted as the result of the transfer. These experiments are rightly regarded as the first decisive proof of the reality of the quantized energy levels that had just been postulated by Niel’s Bohr..."" (DSB).See: Siegmund Brandt ""The Harevest of a Century. Discoveries of Modern Physics in 100 Episodes"", Episode 25, The Franck-Hartz Experiment (1914), pp. 102-104.The volume contains another importent paper ALBERT EINSTEIN ""Beiträge zur Quantentheorie"", pp. 820-828. First edition. ""In this paper.... two considerations are given which are interrelated by a common goal, inasmuch as it is attempted to derive two of the most importent achievementss of quantum theory, viz. Planck's radiation law and Nernst's third law of thermodynamics, in a new manner. The proofs do not involve Boltzmann's equation and are thus based enterely on macroscopic thermodynamics. They do introduce, however, the quantum hupothesis. (Einstein points out that the alleged 'proofs' which try to derive the theorem of Nernst from the mere fact that the heat capacity of all substances goes to zero at absolute zero temterature, are not genuine)."" (Cornelius Lanczos).Weil No 67.‎