8 8 4 C A L E N D A R O F A B S T R A C T S F E B R U A R Y 1 9 2 9 866. From Rosalie Shalit [London, after 30 January 1929] As a student at the University of London’s Royal College of Science, requests a copy of Einstein 1929n (Doc. 365). AD. [48 307]. 867. From Elieser Raphael Cohen Wilmersdorf, 31 January 1929 Immediately after receiving AE’s letter (nonextant), he telephoned O. Warburg, who un- fortunately had left for Palestine and will only return in May. ALS. [45 764]. 868. From Ernst Grah Charlottenburg, 31 January 1929 With the progress of science, time travel may come true and give a higher sense of life. We do not know the direction of time. A repetition of yesterday cannot be observed be- cause our memory would then also go back a day. Does relativity say anything on these questions? Attaches his writing on violin construction. Atoms in metal are gyroscopes. After turning off the magnetizing current, rotated iron rod should lose its magnetism more slowly than a non-rotated one. This would give some information on the still un- clear process of steel hardening. ALS. [46 475]. 869. Paul Ehrenfest to Elsa Einstein Leyden, 31 January 1929 Requests offprints of recent work (see Doc. 393, note 1). Was informed of rumors to the effect that AE is to visit Holland in February, and has denied them by referring to AE’s health condition. He asks about the identity of “L. K.,” author of an interview just pub- lished in the Nieuwe Rotterdamsche Courant (see Appendix J). Tania has a difficult task in Jena and Göttingen and later plans to work in the Netherlands for a few weeks. TLSC. [10 188]. 870. To Georgi I. Maneff [?, February 1929] In reply to Abs. 858, finds four errors in Maneff’s manuscript that are egregious enough so as not to send it to the Zeitschrift für Physik. Does not understand how Maneff can state that all the relativity experts committed such a blunder. ALSfX. [17 054]. 871. From Fritz Haber [?, February 1929] Holzer visited him with AE’s letter. Could not make any sense of the invention. Sent him to O. R. Herzog. ALS. [12 353]. 872. Elsa Einstein to Martin Buber [Berlin,] 1 February 1929 Both she and AE welcome the opportunity to hear Buber address a small group in their apartment. It is important to inform wider circles of the planned youth village and of spiritual principles of Jewish education. TLS. [72 151]. 873. From H. Foerster Berlin, 1 February 1929 In reply to Abs. 853, expounds on his train of thought regarding the proposed expe- riments. ALS. [25 64]. 874. From Kurt Neufeld Berlin, 3 February 1929 Tries to interpret the Michelson experiment on the grounds that the law of reflection in a moving system viewed from the rest system is no longer valid. TLC. [25 179]. 875. From Gerda Philipsborn [Berlin,] 3 February 1929 The newspaper reported a certain “Einstein Electrochemical Process Ltd.” Proposes to authorize her cousin, Albert L. Mond, a well-known lawyer, to take care of correcting the false news. Requests to sign and forward to Mond the attached letter (Abs. 880). TLS. [46 094]. 876. To Kurt Neufeld [Berlin, after 3 February 1929?] In response to Abs. 874, explains Michelson experiment for a stationary system in light of Lorentz contraction. ALS. [25 180]. 877. From Paul Biefeld Granville, OH, 4 February 1929 Reminds AE of their being classmates at the Zurich Polytechnic. Requests offprints of recent papers. Is sorry for having been ill when AE visited the Yerkes Observatory in 1921. Participated in two eclipse expeditions within the United States. ALS. [45 601].