2 1 8 D O C U M E N T 1 5 1 O C T O B E R 1 9 1 9
[3]Koch had joined the Hamburg faculty one month earlier (see Reich 2000, p. 52). For the Bonn
faculty’s nationalist political attitude regarding this appointment, see Doc. 100, especially note 5.
[4]A week earlier, Einstein complained to Carl H. Becker about the Bonn faculty’s poor judgment
in its choice of a candidate (see Doc. 133).
[5]Christian Füchtbauer; Friedrich Paschen.
[6]Sommerfeld’s Assistent, Wilhelm Lenz.
[7]Wilhelm C. Röntgen (1845–1923) was Professor of Experimental Physics at the University of
Munich; Wilhelm Wien; Friedrich Paschen.
[8]Walther Kossel. Kossel 1920 is based on experimental results presented in a thesis (Stenström
1919) written by Karl Wilhelm Stenström (1891–?) under the supervision of Manne Siegbahn (1886–
1977), Deputy Professor of Physics at the University of Lund. Sommerfeld learned of Stenström’s
experiments at a conference organized by Siegbahn in Lund in September. In Sommerfeld 1920,
which appeared in the same issue of Zeitschrift für Physik as Kossel’s paper, Sommerfeld explains the
experimental results with his theory of X-ray spectra.
[9]Wolfgang Pauli (1900–1958) was a student at the University of Munich. His calculations, pub-
lished as Pauli 1919a, showed that from the observed values of the anomalous motion of Mercury’s
perihelion and of the gravitational light deflection no argument can be advanced against Weyl’s
theory.
[10]Gustaf Granqvist (1866–1922) was Professor of Physics at the University of Uppsala. Sommer-
feld had just returned from a visit to Sweden, where he had met with Granqvist and Manne Siegbahn
around 1 October (see Arnold Sommerfeld to his wife, Johanna, 2 October 1919, GyMDM, Sommer-
feld Papers).
[11]Johanna Sommerfeld (1874–1955); the Sommerfelds were distraught at the drowning death on
10 June in the Ammersee of son Arnold Lorenz (1904–1919), news of which was widely circulated
among colleagues and friends. Sommerfeld thought of canceling his planned trip to Sweden and
wrote to Siegbahn on 27 July: “During the last weeks I have experienced unending grief. Not only the
general political misery, but also a special family tragedy has befallen me. A [beloved] 15-year-old
son with great promise has drowned while swimming!” (“Ich habe in den letzten Wochen unendlich
Schmerzliches erlebt. Nicht nur das allgemeine politische Elend, auch ein besonderes Familienun-
glück hat mich getroffen. Ein [lieber] hoffnungsvoller Sohn von 15 Jahren ist mir beim Baden ertrun-
ken!” Arnold Sommerfeld to Manne Siegbahn, 27 July 1919, SSRAS, Manne Siegbahn Papers, in
Eckert and Märker 2004, pp. 48–50).
[12]On 30 September 1919, while in Stockholm, Sommerfeld found lines on a spectrogram taken
earlier by Manne Siegbahn that Sommerfeld first interpreted as belonging to the as yet undiscovered
element 85, named “eka-iodine” (see Arnold Sommerfeld to Adalbert Rubinowicz, 1 October 1919,
Warsaw, in private hands).
151. To Pauline Einstein
Leiden. Sonntag [26 October
1919][1]
Liebe Mutter!
Eine Woche schon bin ich hier bei Ehrenfest in Leiden und erlebe schöne Zeiten.
Es war bis jetzt immer schönes Wetter, das wir reichlich zu Spaziergängen ausnütz-
ten. Abends machen wir Musik. Natürlich ist auch viel von Wissenschaft die Rede
Gestern war ich mit Ehrenfest und Lorentz in der Akademie-Sitzung, wo Lorentz
über die allgemeine Relativität und das Ergebnis der englischen Expeditionen