D O C U M E N T S 1 5 1 , 1 5 2 A P R I L 1 9 2 2 1 4 3 151. To Charles-Eugène Guye Berlin, 18 April 1922 Dear Colleague, First of all, my heartfelt condolences on the heavy loss you and science suffered. Langevin told me in Paris that your brother became the tragic victim of an errone- ous medical theory. As regards the presentation in Geneva, I have to seek your kind forbearance, as I am so very occupied that I cannot think of taking a special trip to Geneva. Nor can it be assumed that I would be coming to Switzerland anyway in the near future, as the lethal valuta conditions always force me to bring my boys to Germany. In our seminar we took a detailed look at your paper on the law of electron motion and were unanimously of the opinion that your confirmation of the theory is the most precise of them all. Please don’t be indignant that I went to Paris before I had been to Geneva the trip was necessary in the interests of international relations without that I would not have gone. The scientific literature provides nicely for the promulgation of rel- ativity theory. In great respect, yours. 152. To Romain Rolland [Berlin,] 19 April 1922 Highly esteemed Romain Rolland, Only today do I manage to thank you for your kind letter. I am glad that my stay in Paris went so harmoniously and I have the happy conviction of having con- tributed toward bringing minds a little closer together. It particularly pleases me that I did not see any trace of triumphant pride or bravado, only people filled with a sense of responsibility. I see it as the main difficulty here as well as in Paris that such a rigid conviction exists about the causal relations and about “the guilt,” mak- ing it very hard to go beyond it. Personal contacts between people from both camps are consequently difficult and yet would definitely be necessary for a restoration of relations to gradually eliminate the mistrust on both sides.