3 1 2 D O C . 3 7 3 A P R I L 1 9 2 0 you here is simply a “love-letter sample.” The only thing of serious importance to me is, at most, that you understand that “the Leyden University Fund” foundation is a very nice establishment indeed. Now, do what you like. I am, in every way, at your disposal. Why is confirmation of your professorship by the government being delayed so long?—Probably it’s because, owing to Bolshevist behavior (as leaders and propa- gandists) by some professors in the country,[21] the Minister possibly still first has to ascertain in Berlin whether you too aren’t such a Bolshevism propagandist. For, the more famous you are, obviously, the more careful the Minister has to be about not drawing you, as a potential agitator, to his bosom! But we hope that this whole official business is soon put in order. That’s why we (very particularly, my children!!) find it excellent that you are coming to visit us around May 1st or even before!![22] Onnes will arrange directly that you are given the permit in Berlin. [N.B. this time bring along with you from Berlin a dozen small portrait photos for the identity cards, etc.—It’s all so much more expensive here, you know!–][23] If your nomination should be delayed further—in any case, we have the funds in stock to reimburse all your expenses. — • — I would be very grateful if you would bring along Sommerfeld’s book and Fa- jans’: Radioactivity.[24] Newer books cannot be obtained now at all anymore. — • — I am enormously pleased that Dostoyevsky made a great impression on you. I haven’t read The Brothers Karamazov yet, on purpose.[25] I am saving it up for a time when it really grabs me by the scruff of the neck.—Meanwhile, The Idiot by Dostoyevsky is the greatest and finest for me. — • — A short while ago, I heard the St. Matthew Passion for the first time, and an ex- cellent performance of it, at that.[26] What gorgeous and emotive grandiosity. I am already full of impatient eagerness to be able to show you certain pieces of music and to discuss with you a few specific more or less philosophical questions (“in principle, seamless describability by physical means”). — • — If only I could, how much I would like to accompany you when you go to Scan- dinavia or wherever else.[27] Oh, if only I were younger and more mobile! — • — Consider once, in a quiet hour, whether you can’t think up a few interesting “cryogen things.” It really is so sad that we still know absolutely nothing about the phenomenon of superconductivity and its destruction by a magnetic field.[28] — • —