6 1 4 C A L E N D A R 1 9 2 0
deliberates on the deduction of the development of the eye
from the law of cone refraction of light. Provenance: IsJHU.
[43 715].
2-page TLS from Springer publishing house. Acknowledges
receipt of the manuscript of Einstein’s Leyden inaugural
lecture “Aether und Relativitätstheorie” via Arnold Berliner.
The lecture will be printed in 3,000 copies. Offers 20% of
the store price or 50% of the net profit. Accepts Einstein’s
decision to retain the translation rights. Provenance:
GyHeidS, Mappe Einstein, E-24. [41 1059].
April 24 1-page ADS in Erich Mendelsohn’s hand. “Vollmacht [i/
I]ch erteile hiermit für alle Angelegenheiten die den Bau des
auf dem Gebäude des astrophysikalischen Instituts in Pots-
dam zu erbauenden Turmspektrographen betreffen, Herrn
Dr. E. F. Freundlich–Neu-Babelsberg Generalvollmacht.
Potsdam, den 24. April 1920 ‘Einstein Spende’. Albert Ein-
stein.” Provenance: GyBKb, Mendelsohn-Nachl., Korre-
spondenzmappe Einstein-Mendelsohn. Hentschel 1997,
p. 54.
3-page ALS from Gaston Moch in Paris, temporarily in
Wiesbaden. Requests permission to translate Einstein 1917a
(Vol. 6, Doc. 42) into French. As to his competence, refers
to professors Violle, Painlevé, and Hadamard. Provenance:
IsJHU. [44 462].
April 27 1-page TLC to Vieweg publishing house. Sends the draft
contract of the Methuen publishing house (presumably
enclosed in Doc. 390; see entry of after 22 April) regarding
English edition of Einstein 1917a (Vol. 6, Doc. 42). Accepts
the terms for the British edition, but the clause on the Amer-
ican publication does not address an extra compensation for
the addenda, therefore he postpones signing the contract
until Vieweg provides 1.5 cents per copy for these addenda.
Provenance: IsJHU. [42 035].
around April 27 Meets with Niels Bohr in Berlin.
April 28 AKS from Julio Rey Pastor, temporarily in Leipzig. Upon
receiving Einstein’s consent to Rey Pastor’s personal and
written invitations (see Doc. 365), informs that an official
letter of invitation to Spain will arrive in a few days. Ein-
stein may choose between French and, for a narrower audi-