D O C U M E N T 3 8 6 O C T O B E R 1 9 2 6 3 7 5 I am repeatedly receiving reports in a tone of Schadenfreude of your changed po- sition relative to Zionism. Not only critical, but also derogatory statements that al- legedly originated with you are being circulated. I know that you have not only had pleasant experiences. However, I cannot truly imagine that your position relative to our movement would be decisively influenced by such experiences.[3] Since you, as I hear, are reportedly of the opinion that I also abused you, I will refrain from any attempt to exert renewed influence, although your opinion was, in my view, incorrect.[4] I ask you now for a brief message about the actual state of affairs. Best regards, sincerely yours, Kurt Blumenfeld 386. From Paul Langevin Paris, 10 Rue Vauquelin Paris (5th), 20 October 1926 My dear friend, What I have to tell you today concerns technology, in which I know you take an interest. Regarding my ultrasonic devices, you told me, two or three years ago, that Mr. Anschütz would perhaps be disposed to take charge, in Germany at least.[1] The matter has taken shape since that time, and now we have well-designed de- vices for probing, signaling, and detection. If the matter really interests Mr. An- schütz, we would be very happy to provide him with information—I myself am at his disposal and he could also contact the company that has the patent licenses— the Condensation and Mechanical Applications Company (C.M.A.C.), 10 Place Edouard VII in Paris (8th arrondissement). The German patents were granted al- ready some time ago. If you do not have the chance to see Mr. Anschütz soon, give me his address and I will send him any documents he may want.— Are you coming to Paris? I would like to discuss many things with you, in par- ticular the absurd situation of international scientific relations.[2] The ideas of Louis de Broglie, about which I remember you speaking for the first time on the shores of Lake Geneva,[3] seem to make their way very quickly, and Schrödinger is doing very nice things in this direction.[4] Here is another field in which mathematical preparation is very useful. Soon, physicists will need to know a world of things from birth. Please give my respectful compliments to Mrs. Einstein. Kind regards to you, P. Langevin