D O C U M E N T 1 7 5 N O V E M B E R 1 9 1 9 2 4 9
ALS. [9 449].
[1]Presumably Doc. 160, and a letter from Elsa Einstein, responding to Ehrenfest’s request that she
report on Einstein’s trip home from the Netherlands (see Doc. 154).
[2]Reference to translations of, e.g., “Revolution in Science. New Theory of the Universe. Newto-
nian Ideas Overthrown” and “The Revolution in Science. Einstein v. Newton. Views of Eminent Phys-
icists,” in The Times (London), 7 and 8 November 1919, respectively.
[3]Drawings by the younger Ehrenfest daughter, Anna, are enclosed (see Illustration 6).
[4]Erwin Freundlich.
[5]Lorentz 1919a.
[6]The same day Ehrenfest inserted “Krit. Darstell. der Th. v. Einstein” in his diary (see entry
no. 5423 of 24 November 1919, NeLR, Ehrenfest Archives, Notebooks ENB:1-25).
[7]Csárdás is a lively Hungarian dance.
[8]Lorentz, in a letter to Einstein of 6 June 1916 (Vol. 8, Doc. 225), made just this point, that Mach’s
principle, as incorporated into general relativity, did not appear to explain why inertial motion with
respect to the fixed stars (any more than motion against the ether) could not be observed by experi-
ments. See also Einstein’s reply to Lorentz 17 June 1916 (Vol. 8, Doc. 226).
[9]For Ehrenfest’s earlier allusion to such a regular position involving periodic visits to Leyden, see
Doc. 109.
[10]The Leyden University Fund (Leidsch Universiteitsfonds) collected its funds from donors (stu-
dents and alumni), was managed by its University Council (Universiteitsraad), and was represented
in the University Senate by an executive committee (Commissie van uitvoering) (see Jaarboek 1920,
p. 57).
[11]Leonard S. Ornstein (see note 18); Frits Zernike (1888–1966), Extraordinary Professor of
Mathematical Physics and Theoretical Mechanics at the University of Groningen.
[12]More than two months earlier, Einstein had cited his reluctance to “turn his back” on Max
Planck in Berlin (see Doc. 103). The square brackets are in the original.
[13]See Pringsheim 1910, particularly pp. 271–299. Astrophysicists did not agree with Julius’s in-
terpretation of observed solar redshift as being due to anomalous dispersion (see his remarks in his
letter to Einstein, 26 August 1911 [Vol. 5, Doc. 280]). Later, prominent astronomers opposed it (see,
e.g., St. John 1915 and Royds 1915). For a historical review of Julius’s theory of the solar atmosphere,
see Hentschel 1991a.
[14]Lorentz 1919b and 1919c that Einstein studied in Berlin “with great pleasure” (see Doc. 160).
[15]Hendrik A. Lorentz, as Extraordinary Professor (buitengewoon hoogleeraar) of Mathematical
Physics, habitually offered a course (college) in theoretical physics on Mondays at 11
A.M.
[16]At this point, Ehrenfest drew an arrow pointing to the end of the paragraph where he appended
the titles of journals to which Einstein might consider submitting a review: “‘Naturwissensch’ oder
Physikal Zeitschrift.”
[17]In his diary, Ehrenfest inserted “Zion-Mathemat.” before entry no. 5428, before 24 December
1919, NeLR, Ehrenfest Archives, Notebooks ENB:1-25.
[18]Leonard S. Ornstein (1880–1941), Professor of Theoretical Physics at the University of Utrecht
and chairman of the Dutch Zionist League, was a recipient of the letter of invitation to the Zionist
conference on education sent to Einstein and Ehrenfest three days later (see Doc. 179 and list of invi-
tees appended to letter of invitation, 25 November 1919, IsJCZA, L12/65). Ornstein had been
involved in plans for the Hebrew University since 1913 when Chaim Weizmann invited him to attend
discussions on the university at the 11th Zionist Congress in Vienna (see Weizmann to Ornstein,
10 August 1913, in Yogev et al. 1974, p. 133). On Ornstein’s Zionism, see Unna 2000, pp. 340–341.
[19]In his response to Shmarya Levin’s invitation to the planned conference, Ehrenfest stated that
he would like to participate in the discussions. However, since he was currently stateless as a conse-
quence of losing his Austrian citizenship at the beginning of the war, he would only be able to travel
to Switzerland if the Zionist Organisation could provide him with a “special passport” (Ehrenfest to
Shmarya Levin, 3 December 1919, IsJCZA, L12/65).
[20]In 1919, Planck was awarded the Nobel prize in physics (for the year 1918) for his discovery
of energy quanta; Johannes Stark won the prize for the year 1919 for his discovery of the Doppler
effect in canal rays and the splitting of spectral lines in an electric field (Stark effect). See also
Doc. 169 and its note 1.