C A L E N D A R O F A B S T R A C T S 1 9 2 7 9 5 1 748. From Edwin B. Wilson Boston, 11 February 1927 As editor of the Proceedings of the National Academy of Sciences, invites AE to submit a contribution. Draws attention to recent publications in the journal by George D. Birk- hoff, which he is enclosing, and Luther Eisenhart, and expects AE may wish to com- ment, especially since the papers seem devoid of physical content. TLS. [47 716]. 749. From Arthur J. Kraus London, 12 February 1927 Has urgent news that he wishes to convey to AE in person, whom he begs for a meeting (see also Abs. 516). TLS. [47 312]. 750. From Toni Mendel [Shellal, Egypt,] 13 February 1927 Has arrived at the end of their trip, near Aswan, and loves Nubia. ALS. [120 476]. 751. To Ladenburg, Thalmann & Co. [Berlin,] 14 February 1927 In reply to Abs. 735, agrees to the proposed reinvestment of the funds. ALS. [144 394]. 752. From Wilhelm Romeiser Berlin, 14 February 1927 After listening to H. Reichenbach’s lecture on the radio, reports on his long researches regarding the incorrectness of Newtonian theory as applied to the motion of birds, air- planes, and cars, proving that their kinetic energy liberates moving objects from the in- fluence of the gravitational field. Hopes AE agrees. TLS. [25 243]. 753. To Wilhelm Romeiser [Berlin, after 14 February 1927] In reply to Abs. 752, indicates that Romeiser’s elaborations are based on a misunder- standing. The theory of relativity differs only insignificantly from Newton’s theory in the practical cases enumerated. ALSf. [25 244]. 754. From Hans Albert Einstein Dortmund, 15 February 1927 Thanks for the 20 M (see Doc. 474). Enjoys his work and the colleagues. As part of his bridge projects, has designed a bar of ca. 100 m. May decide to move outside the city, which is rather dreary. ALS. [144 052]. 755. From Teodor Schlomka Halle a. S. 15 February 1927 Disputes AE’s three arguments against a flight test in Doc. 475. The transformation AE refers to is not for a rotating system. Repeats his considerations expounded in Doc. 442: Considers a sphere with positive volume charge and an equal negative surface charge if this sphere rotates, one has no electric but a magnetic field. A translating sphere pro- duces neither an electric nor a magnetic field. The effect is too small to be observed on board transatlantic ships because of their low velocity. Considers a flight test hopeful. ALS. [21 502]. 756. To Teodor Schlomka Berlin, [after 15 February 1927] Contradicts Abs. 755, but endorses flight experiment with help of Hugo Hergesell (see Doc. 483). Requests research plan. ADft. [21 502.1]. 757. To Hugo Bergmann Berlin, 16 February 1927 In reply to Abs. 742, the PAW is solely engaged in the exchange of journals, and does not send them as gifts to non-members. The Hebrew University should itself have peri- odic publications. Inquires why the Scripta has been dormant. ADft. [36 934]. TLS. [67 737]. 758. To Franz Ullstein [Berlin,] 16 February 1927 Thanks for having listened to Stephan Lux, who had been recommended by Miss Friedländer (see Abs. 745). AE had assumed that Lux had a project description ready. Without it, the matter is futile. ALS. [48 641].