2 4 D O C U M E N T 6 A P R I L 1 9 2 3 [10]These results were published in Born and Heisenberg1923b and played an important role in the subsequent development of quantum mechanics see Einstein and Born 1969, pp. 113–114. [11]Werner Heisenberg (1901–1976) was a student at the University of Göttingen Arnold Sommer- feld (1868–1951) was Professor of Physics at the University of Munich Wolfgang Pauli (1900–1958) was Privatdozent at the University of Munich and working with Niels Bohr in Copenhagen. For Som- merfeld’s trip to the United States, see Eckert 2013, pp. 338–360. [12]Born and Heisenberg 1923a. [13]Born 1923, which is an expanded edition of Born 1915. [14]Electronic theories of covalent bonding in the context of solid state theory are discussed in §40 of Born 1923, pp. 752–756 (see also Born and Kornfeld 1923). For a historical discussion of the the- ory of chemical bonding from the point of view of Bohr’s theory in the early 1920s, see Kragh 2012, especially chap. 6. [15]Max Planck had informed James Franck in December 1922 that he was on the short list of suc- cessors to the late Heinrich Rubens (1865–1922), Professor of Physics at the University of Berlin (see Lemmerich 2011, pp. 100–101). [16]Gustav Hertz (1881–1975) was a physicist at the N.V. Philips’ Gloeilampenfabrieken in Eind- hoven. [17]In the New York Times of 22 March 1923, a report entitled “Einstein to Announce Theory ‘Sur- passing Even Relativity’” stated: “A new discovery which it is believed will create an even greater sensation than his theory of relativity has been announced by Professor Albert Einstein, famous Ger- man scientist, upon his arrival at Kantara, Egypt, after his recent trip to Japan with his wife. Professor Einstein is withholding the details of the discovery, stating merely that it concerns the connection between the earth’s power of attraction and terrestrial magnetism.” In December 1924, Einstein would refer back to “false rumors” that had arisen two years earlier to the effect “that I had found a new rela- tionship between relativity and the theory of terrestrial magnetism” (see Doc. 396). For more on Ein- stein’s interest in terrestrial magnetism, see Doc. 87, note 4. [18]Perhaps Mie 1921 and/or 1922. [19]See Hilbert 1922, 1923. For further historical discussion of Hilbert’s interests in the founda- tions of mathematics and proof theory in this period see Ewald and Sieg 2013, especially chap. 3, pp. 418–431. [20]For Einstein’s open letter of resignation from the League of Nations’ International Committee on Intellectual Cooperation, see Einstein to Pierre Comert, 21 March 1923 (Vol. 13, Doc. 447). [21]Gustav Born (*1921). [22]Coudenhove-Kalergi 1922. [23]Max Planck. [24]Born lectured at the Deutsche Physikalische Gesellschaft on 9 March 1923 on “sublimation heat and dipole moment of hydrogen halides and on the quantum theory of the helium spectrum” (“Sublimationswärme und Dipolmoment der Halogenwasserstoffe und über die Quantentheorie des Heliumspektrums” see Verhandlungen 1923, No. 1, p. 11). [25]Heinrich Rubens. 6. To Hermann Anschütz-Kaempfe[1] [Berlin,] 8. IV. 23 Lieber Herr Anschütz! Ich freute mich sehr über Ihren lieben Brief und bin sehr neugierig auf das nied- liche Refugium und auf den Kreisel[2] Gleich kann ich von hier nicht wieder abrei-