3 8 4 D O C U M E N T 4 5 8 M A R C H 1 9 2 3 I was extremely pleased that you were still able to see my wife[2] and was touched straight to my heart that you spoke spontaneously about coming to Ley- den I hadn’t dared to ask you about that.—But now, naturally, I will joyfully and resolutely jump at the opportunity: I beg you please to choose: Around 11 April or around 20 May (= Whit Sunday)—Later I am going to have to conduct such an enormous number of examinations, partly in Leyden, partly in Delft, that any con- tact between us would be impossible.– “Around” gives you some freedom of choice:– I entreat you: (A) To inform me as soon as possible what you choose, with exact indications of the limiting dates (B) To then also—forgive the impudence of the request!—really keep to it.– I’d prefer most if Ilse replies to me!!!– I just heard: From 13 May until circa 5 June Lorentz will be in England. From 5 May–27 May De Sitter likewise.[3] Around 11 April—therefore, e.g., from 7 April onwards you’ll encounter everyone! Cord. regards, yours, P. Ehrenfest 457. From Richard Stern[1] Berlin, 28 March 1923 [Not selected for translation.] 458. From Hermann Anschütz-Kaempfe Kiel, 23 Heikendorfer Way, 31 March 1923 Dear, esteemed Professor Einstein, I do not know whether these lines will find you in Berlin already or will be wait- ing for you from your two messages from Japan and Spain[1] I gather, though, that it should be right about now. We, i.e., my wife and I, have been here for 14 days and want to stay another 4 weeks or so then all sorts of urgent things summon us back to Lautrach. It would be nice if you came while we are here and there is enough interesting work to do. The new compass, in its first model, has meanwhile been thoroughly tortured the entire winter and behaved itself quite splendidly we are just about to put the second sphere, in a slightly improved form, onto the testing stand. In my letter to you at the University of Tokyo I reported to you about your apart- ment now everything aside from a few little details is ready there and it is awaiting