C A L E N D A R O F A B S T R A C T S M A Y 1 9 2 8 8 5 1 517. To Bruno Meyermann [Berlin] 3 May 1928 Thanks for the interesting information on a secular fluctuation of the Earth’s rotation. Curious whether the data on the motion of Mercury’s perihelion are to be modified. Asks for the cause of this fluctuation. TLC. [17 183]. 518. To Sergei Fedorovich von Oldenburg Berlin, 3 May 1928 Confirms receipt of the diploma of honorary membership in the Academy of Sciences of USSR (Abs. 454). TLS. [70 695]. 519. To Georges Oprescu Berlin, 3 May 1928 In reply to Abs. 566, declares that the cardiologist forbids him from attending the July session. May he send a representative and, if so, must it be H. A. Krüss? TTrL. [34 987]. 520. To Léon Rosenfeld [Berlin,] 3 May 1928 In reply to Abs. 501, agrees to support his application to the International Education Board. TLC. [48 154]. 521. To August Schulenberg [Berlin,] 3 May 1928 In reply to Abs. 502, explains that ideas similar to Schulenberg’s had already been dis- cussed in the early nineteenth century. Interference phenomena cannot be explained this way. Maxwell’s bridge connecting electrodynamical phenomena with light also gets lost. TLC. [25 271]. 522. To Henrik G. Söderbaum [Berlin,] 3 May 1928 In reply to Abs. 503, is pleased to belong to the Swedish Academy of Sciences. Has also received the certificate. TLC. [30 234]. 523. From Ernst Eckhardt Eisenach, 3 May 1928 Convinced that AE is free of academic dogmatism and that new ideas are created not only by overtrained guild members but also by persons not burdened by specific knowl- edge, offers to give a more detailed draft of his program. ALS. [25 053]. 524. From J. David Thompson [Washington, D.C.,] 3 May 1928 IIIC had asked the American National Council on International Intellectual Cooperation for its opinion on a proposal to sign an international convention on legal protection of scientific property. The attached opinion of the National Research Council ([34 1004]) is an emphatic rejection. TLS. [34 1003]. 525. From Carl B. Hess Chicago, 4 May 1928 A Jewish boy of fifteen, getting interested in Zionism, asks whether the University in Palestine [Hebrew University] would admit students who do not intend to live there. ALS. [46 677]. 526. From Hugo A. Krüss Berlin, 4 May 1928 In reply to Abs. 516, accepts AE’s proposals. Will present himself before the next visit to Paris. Wishes complete recovery. TLS. [34 848]. 527. From Bruno Meyermann Göttingen, 4 May 1928 In answering AE’s question in Abs. 517, the reason for fluctuation may be that the Earth’s mantle, separated from the core by viscous magma, drifts to the west by friction. The fluctuations in the friction appear to us as time fluctuations. Stronger friction results in shorter years and inversely. TLS. [17 185].