2 8 2 D O C . 3 3 5 M A R C H 1 9 2 0 335. To Paul Ehrenfest [Berlin, 1 March 1920][1] Dear Ehrenfest, I am writing only now because it was as if I had been crippled by my mother’s severe illness. A week ago we carried her to her grave.[2] It was a terrible time!– I am now writing the inaugural lecture.[3] The semester continues here until the end of March.[4] When should I come to Holland? I am very much looking forward to the inaugural lecture, and generally to our reunion. The violin maker is balking instead of working he’s just a drunken sod—you’d be really amused by that fellow but I fear we aren’t going to get the violins in time.[5] My calculation was magnan- imous. In this bankruptcy, one loses all feel for the powers of ten.[6] The correct fig- ures were 16500 + 239 (if I am not mistaken) = 16739 which leaves 3261 marks for you. Our money is growing ranker and prices handsomer by the minute. My cousin recently paid 30 marks for an apple at a restaurant. I am constantly brooding about extending the theory of relativity, but always come up against a wall.[7] About an entirely different matter: the experimental find- ing on the Bjerrum band looks like this.[8] The vanishing of absorption at 0 is the extraordinary thing. It lends support to the argument that, in rotation, the permis- sible motions lie not with the quantum numbers n but rath- er with . It’s a very re- markable thing.[9] Have you seen the paper by Grebe and Bachem about the redshift in Zeitschrift für Physik? Even if the redshift is still not confirmed thereby, it is clear that the determinations have been decidedly erroneous until now.[10] Now Epstein doesn’t have anything at all. I wrote to Zurich again on his behalf.[11] If it doesn’t help, we should try to procure him a position in America. Would you possibly have any contacts there? To whom might I be able to write? The Jerusalem affair (university) is moving briskly forward.[12] The Londoners are following their own heads there seems to be little sense in racking one’s own brain about it. In the end, the people do matter more than the formal structure.[13] Lorentz and Kamerlingh-Onnes wrote me exceedingly kindly and warmly a month ago [14] but I still have not managed to respond. Give them my cordial regards and ask them please not to hold it against me. I cannot tell you how glad I am to see you θ 0 n 1 2 -+--