D O C U M E N T 1 5 2 J U N E 1 9 2 1 1 9 5
versprochen. Bist Du mit Deiner Reise nach Deutschland und nach
Schreib ein bischen darüber.
Ende Juli und Anfang August verbringe ich mit meinen Jungen auf dem Lande,
wahrscheinlich an einem See
Wir wollen hauptsächlich
Herzliche Grüsse an Euch alle, auch die
Freundlich wird Dich besucht haben. Ihr werdet ihn ein bischen gezupft haben,
kann ihm nur gut
Hoffentlich spricht er auch
Ich habe Frost
Julius’ Arbeiten sehr empfohlen Er war durch
frühere Publikationen überall in Misskredit
ALSX. [9 561].
Presumably a reference to Einstein’s mother-in-law, Fanny Einstein (1852–1926), Ilse and Mar-
got Einstein, and Anna, the domestic helper.
Einstein and Elsa had just returned from their three-month-long trip.
Ehrenfest and Van Aardenne had arrived in Berlin on 10 May, during Einstein’s absence, for a brief
visit to purchase equipment and to meet Abram Joffe and Dmitry Rozhdestvensky (see Doc. 148 and
Margot Einstein to Frieda Huber, 28 April 1921 [SzBL] [123 170]). Einstein had asked Ilse Einstein
to intercede with the Police Presidium in Berlin on Ehrenfest’s behalf, so that he could obtain a visa
(see 27 April 1921 in Calendar).
Presumably a reference Einsteins’s passage through the Netherlands from England to Berlin
without stopping in Leyden.
The goal of the American Jewish Physicians Committee had been to raise one million dollars
for the faculty of medicine (see before 20 April 1921 in Calendar). By the end of the tour, $250,000
had been subscribed to for the medical faculty, and $25,000 for the University Library (see 18 and 21
May 1921 in Calendar).
Solomon Ginzberg confirmed that the Jewish physicians’ efforts where much more successful
than the fund-raising among the wealthier members of the community (see Solomon Ginzberg to
Patrick Geddes, 23 June 1921 [IsJCZA/L12/66]).
For Weizmann’s original invitation, see Chaim Weizmann to Kurt Blumenfeld, 16 February 1921.
Einstein had intended to visit Leyden directly after his planned participation in the Solvay Con-
gress in April (see Docs. 30). He subsequently informed Ehrenfest and Lorentz that he would have to
postpone his lectures until the summer semester (see Docs. 83 and 57).
Federigo Enriques (1871–1946), Professor of Projective and Descriptive Geometry at the Uni-
versity of Bologna, had invited him on 19 January 1921 (see Calendar).
Ehrenfest had visited colleagues in Germany and toured laboratories and libraries in Berlin, Göt-
tingen, and Munich. He was also invited to lecture at the German University of Prague.
For details regarding the planned vacation with his sons, see Doc. 153.
Russian for “boys”; a reference to the Ehrenfest children.
Erwin Freundlich (1885–1964) was Assistent at the Kaiser Wilhelm Institute of Physics. As
early as 1919, Einstein had expressed frustration with Freundlich’s work on gravitational redshift
using stellar statistics (see Einstein to Elsa Einstein, 28 October 1919 [Vol. 9, Doc. 152a, in Vol. 10],
and Einstein 1921f (Vol.7, Doc. 56).
See Doc. 142.
Julius’s persistent refusal to abandon his anomalous dispersion theory of solar spectral phenomena
in light of measurements of the solar redshift, which appeared to go against his theory, had greatly
injured his reputation among solar astrophysicists. Ehrenfest had asked Einstein to seize every opportu-
nity to put in a good word for Julius (Paul Ehrenfest to Einstein, 8 December 1920 [Vol. 10, Doc. 225]).