3 7 6 D O C U M E N T S 3 8 7 , 3 8 8 O C T O B E R 1 9 2 6 387. Presenting Rupp 1926b to the Prussian Academy of Sciences [Einstein 1926w] Presented 21 October 1926 Published [after 21 October 1926] In: Preußische Akademie der Wissenschaften (Berlin). Physikalisch-mathematische Klasse. Sitzungsberichte (1926): 333. 2. Thereupon Mr. Einstein submits a paper by Dr. E. Rupp (Göttingen): “On the Interference Properties of Canal Rays.”[1] Two experiments proposed by Einstein (“grating experiment” and “mirror- rotation experiment”) on the interference properties of light emitted by canal rays (mercury canal rays) are performed. Both experiments prove, in full conformity with the wave theory of light, that the atom participates in the generation of the in- terference field not only by an instantaneous process, but by a process of the dura- tion of the order of magnitude of the decoherence time of classical theory. This is proved by showing that the waves attaining interference, which must of course originate from one and the same particle, issue from spatially different locations with respect to the motion of the particle, a temporal difference in the emission of those waves therefore follows from this spatial difference. 388. Proposal to Publish Jakob Grommer’s Book [Berlin,] 21 October 1926 Dr. Grommer has written a textbook in Hebrew that is an introduction to higher mathematics for self-study, in fact at the request of the culture committee of the Zi- onist administration (1919).[1] It would be regrettable if no use were made of this work, the more so as I often hear complaints about the lack of scientific books in Hebrew. In any case, there should be serious consideration as to whether the book, as it stands, is suitable for publication, and whether publication seems feasible from the commercial standpoint. A. Einstein