C A L E N D A R O F A B S T R A C T S A P R I L 1 9 2 8 8 4 7 472. From Raschko Zaycoff Sofia, 6 April 1928 Emphasizes that he has turned into a different man, and thanks AE and Elsa for their as- sistance. Will pay back the loans from L. Szilard and H. Simon. He has an Assistent po- sition at the University of Sofia, and is doing experimental work. Has not, however, given up his plan to follow his theoretical interest in the footsteps of AE’s field theoret- ical approach, namely, to treat field physics with quantum mechanics by Volterra’s func- tional mathematics. ALS. [24 192]. 473. From Det Tekniske Forsøgsaktieselskab [Copenhagen,] 9 April 1928 Agreement on selling applications G. 75753 and G. 75754 for patenting AE’s and Rudolf Goldschmidt’s joint inventions. TLS. [51 507]. 474. From Curt Schwarz Charlottenburg, 11 April 1928 Regrets that AE and Grommer published something, with a perseverance that would de- serve a better goal, that is completely nonviable and is good only for obscuring the beauty of what we know of the essence of matter by the general theory of relativity. Proposes a theory in which field and matter, gravitation and electricity make a complete unity. Asks AE’s help for continuing the calculations. ALS. [48 445]. 475. From the Swedish Academy of Sciences Stockholm, 11 April 1928 Diploma of AE’s election to foreign member. DIPL. [65 046]. 476. From Georges Oprescu [Geneva, after 11 April 1928] Has been informed by L. Steinig that AE is unwell. Sends best wishes and hopes to see him at the July session. ALS. [34 985]. 477. To Owen W. Richardson Berlin, 13 April 1928 Thanks for notification and for the honor of being nominated. This is yet another encour- aging sign that scholars are aware of the international character of the mission of science. TLS. [85 906]. 478. To the Royal Irish Academy Berlin, 14 April 1928 Has found Abs. 457 after having returned from his holidays. Expresses heartfelt thanks and joy at belonging to their circles. TLS. [95 555]. 479. To Rockefeller Foundation Berlin, 16 April 1928 Proposes Leo Kohn for Laura Spelman stipend. Knows him as secretary of the BOGHU, and has a high opinion of him as a man and as a scientist. TLS. [91 272]. 480. To Emil Rupp Berlin, 16 April 1928 Thanks for the results in Doc. 153. Their interpretation seems to be correct in a first ap- proximation. TLSX. [124 357]. 481. From Gewerkschaft Deutscher Geistesarbeiterverbände Berlin, 16 April 1928 Accepts AE’s proposal of W. von Moellendorff as second representative of German intellectual workers at the International Labour Office. T. Brauer is politically unaccept- able (see Abs. 466). TLS. [46 390]. 482. From Lucien Lévy-Bruhl Paris, 16 April 1928 Sends Lévy-Bruhl 1922 and 1916 as a memento of the days spent together in Davos. ALS. [47 424]. 483. From Curt Schwarz Charlottenburg, 16 April 1928 It is strange that AE spends little time examining others’ work. Advises not to bother about the singularity of an atom because 1,001 nights would not bring success mean- while Schrödinger’s formalism provides every detail of the atomic interactions. AE will accept the new theories as soon as he learns them. One should give up strict determin- ism. Will call for the time of a visit. Proposes a medicine “that must help even privy councilors,” as well as Kaffee Hag (the first decaffeinated coffee). ALS. [48 446].