D O C U M E N T S 7 9 , 8 0 M A R C H 1 9 2 2 9 7 sional considerations.[4] I am working with all spectra as measurement sensors in unknown substances—this particular med. eye I am developing very well (plate sensitization with mineral oil 1/1000 [5000?] spectral[lines?] is very interesting).[5] Do you know about India’s critique of Europe in the book: God’s Conic Sections [Die Kegelschnitte Gottes] (Lange, München, 1920) by Sir Galahad,[6] in which you also play a role (p. 132)—as ideal European, whom Sir Galahad has not dis- covered yet.[7] These secrets will be solved later—after Japan[8] (from Zurich) Have a nice trip and enjoy yourself[9] Zangger 79. To Paul Ehrenfest [Berlin, between 11 and 13 March 1922][1] Dear Ehrenfest, I’m going to be in Paris from 28 March until c. 4 April.[2] Can I come to Leyden then or should I go back to Berlin in order to come 2 weeks later? It is very fine that K[amerlingh] Onnes did that experiment. Yet another glimmer of hope to understand is dashed.[3] Franck informed me about a very nice point regarding the behavior of free electrons towards atoms. I’ll tell you about that then. In other respects I’ll be bringing an empty head along, which, after your consoling assurance, shouldn’t cause any harm. Warm regards to you all, yours, Einstein. I am probably going to Japan now, after all, with my wife departure August or September.[4] 80. From Michele Besso Bern, 42 Ziegler Street, 12 March 1922 Dear Albert, A little card by Vero[1] may have reported to you that I’ve become a grandfather.[2] We just returned from seeing the little grandchild (who, for the sake of convenience, was born in the clinic) and my folks are pointing out resemblances. I believe I can see something peering into this world in expectation of impressions and ready to react with determination to them—so that perhaps in 49 years he, too