V O L . 5 , D O C U M E N T 4 3 9 a , V O L . 8 , D O C U M E N T 5 a 2 1
[4]On the polemic with Walther Nernst, see Einstein to Ludwig Hopf, after 20 February 1912
(Vol. 5, Doc. 364), note 6.
[5]Einstein visited Walther Nernst (1864–1941), Professor of Physical Chemistry at the University
of Berlin, Fritz Haber, Emil Warburg, Heinrich Rubens, and Erwin Freundlich in Berlin from 15 to
22 April 1912.
[6]While in Berlin, Einstein also visited his aunt Fanny (1852–1926) and uncle Rudolf Einstein
(1843–1928), and became reacquainted with his cousin Elsa Löwenthal, née Einstein (1876–1936).
[7]Paul Ehrenfest (1880–1933) was giving lectures at various universities in Europe while search-
ing for a permanent position. For more on Ehrenfest, see Klein 1970. Einstein first met Ehrenfest on
23 February 1912.
[8]Peter Debye had been appointed Professor of Mathematical Physics and Theoretical Mechanics
at the University of Utrecht on 3 February 1912, officially accepted on 18 March, and withdrew from
the University of Zurich on 28 March (see Einstein to Heinrich Zangger, 26 February 1912 [Vol. 5,
Doc. 366], note 11).
[9]On Ehrenfest’s intransigence about religious affiliation, see Einstein to Heinrich Zangger,
26 February 1912 (Vol. 5, Doc. 366), note 12. In the process of accepting his position in Prague in
1910, Einstein declared himself “Jewish” (“mosaisch”), after previously having been registered in
Switzerland as “without religious affiliation” (“konfessionslos”; see Einstein to Jakob Laub,
27 August 1910 [Vol. 5, Doc. 224], note 3, and Count Karl von Stürgkh to Einstein, 15 December
1910 [Vol. 5, Doc. 238], note 1).
Vol. 5, 439a. To Vladimir Varic;ak
[Zurich, 14 May 1913]
Lieber Herr Kollege!
Ich danke Ihnen herzlich für den schönen Käse, den Sie uns geschickt haben. Ihr
Bubi ist ein sehr eifriger Student und immer frohen Mutes. Die Gravitationsarbeit
ist fertig; ich hoffe Ihnen bald ein Exemplar senden zu
können.[1]
Mit besten Grüssen Ihr
Einstein.
[. .
.][2]
AKS (CrZ, R4812b). [91 181]. The postcard is addressed “Gosp. Prof. Dr. Varic;ak Trg Franje Josipa
6 Zagreb Croatien” in Mileva’s hand and postmarked “Zürich Neumünster [------].” The verso shows
a “Schwarzwaldhaus ca. 1881.”
[1]Einstein and Grossmann 1913 (Vol. 4, Doc. 13), which was submitted before 28 May 1913 (see
Einstein to Paul Ehrenfest, 28 May 1913 [Vol. 5, Doc. 441]) and published before 25 June 1913.
[2]A postscript by Mileva Einstein-Maric; (in Serbian), thanking Varic; ak for the cheese, is omitted.
Vol. 8, 5a. From Heinrich Zangger
[between ca. 14 April and 1 July
1914][1]
Lieber Freund Einstein
Ich habe ja schon ein neue Art [von] Quets[ch] gewittert in Berlin, darum habe
ich gar nicht [so] [weiss] getan, als Sie mir die Lage mitteilten. Erst wie Sie selbst
vor Berlin standen wie vor einen Käfig [etc] [u] dann ist [in] Sommer die Schweiz