C A L E N D A R O F A B S T R A C T S D E C E M B E R 1 9 2 8 8 7 5 771. To William J. Brittain [Berlin,] 27 November 1928 Cannot supply the requested information. It cannot be sketched in a few words and would not lead closer to the truth. TLC. [45 660]. 772. From Luitzen Brouwer Laren, 30 November 1928 Informs editorial board of Mathematische Annalen that he has just received O. Blumen- thal’s indictment (Abs. 751), though AE and L. Bieberbach reported receiving it earlier. Requests that the board members inform Blumenthal that they will not assent to Brouwer’s dismissal before the latter has had a chance to present his defense. TLSC. [13 162]. 773. From Rudolf Goldschmidt [Berlin,] 30 November 1928 Sends a poem as an “echo” of Doc. 327. Is performing experiments with asymmetric loudspeaker membranes by placing a small weight on the membrane at different loca- tions and measuring their resonance curves. ALS. [35 498]. 774. From I. G. Haddad Beirut, 30 November 1928 Thanks for AE’s letter (nonextant). It is difficult to find a man who is both Jewish and knows German well but hopes to produce a good translation by also using the French edition. Found Moreaux’s popular book on Einstein’s work confusing. Requests a small photograph of the greatest contemporary scientist. TLS. [42 170]. 775. From Ferdinand Müller Solingen, 30 November 1928 Thanks for AE’s letter of 25 November (nonextant). Sends a manuscript on the physical processes that take place in the violin. TLS. [47 679]. 776. To Robert Weltsch Berlin, [December 1928] H. Bergmann’s manuscript on causality, Bergmann 1929 (see Abs. 749), is currently the hottest topic in the borderlands of physics and philosophy. It reflects a rare knowledge of both fields. It should be published in a journal and perhaps also be made available separately as a book. TTrL. [45 540]. 777. From Constantin Carathéodory Munich, 3 December 1928 Explains that he has postponed his resignation from the editorial board of Mathema- tische Annalen so as not to weaken Hilbert’s position in demanding Brouwer’s dis- missal. Informs AE of Harald Bohr’s idea to dissolve the board in order to form a new one consisting of only four principal editors. Should AE also wish to resign, Springer could consider appointing E. Hecke and H. Weyl only Hilbert and Blumenthal from the former board would still remain. Requests that AE treat this proposal confidentially and solicits his advice regarding other possible options. ALS. [13 163]. 778. “On a Pump, Particularly for Coolers” Berlin, 4 December 1928 Granted patent in Germany for a pump for the device patented in Abs. 338, in which light metals (e.g., potassium) and their alloys are used in place of mercury as working fluid. PD. [93 385]. 779. To Hugo A. Krüss [Berlin,] 4 December 1928 Forwards the invitation to the 21–22 December 1928 session of IIIC. TLS. [95 914]. See also [99 087]. 780. From Arthur LeRoy Cohen Los Angeles, 5 December 1928 A twelve-year-old, sends his paper on Einstein’s relativity for opinion. Asks whether movement exists with its accompanying phenomena such as inertia, in a space that con- tains no other object than the person or mechanism that is trying to get under motion. TLS. [25 043]. 781. From Emil Rupp [Berlin,] 5 December 1928 Apparently upon AE’s suggestion, has performed a version of the experiment proposed in Doc. 277. He placed a thin wire in an electric field of 50 periods and observed a bend- ing of about 0.1 mm when a current of the same period was sent through the wire. The