3 4 6 D O C U M E N T 3 4 8 A U G U S T 1 9 2 6 I would like to use this occasion to let you know something about the Millikan- Kohlhörster tension, which could perhaps contribute toward the restoration of friendly relations: namely, about the issue of the brief notices about cosmic radia- tion that appeared in Science and Nature.[7] Those communications were Mil- likan’s notes for his talk at the scientists’ convention.[8] Naturally, with you he did not go into any great length about their prehistory, because he only needed the data and could, and did, add the rest orally. He in fact did express his highest recognition of Kohlhörster. After the talk, a member of the press asked him for just an excerpt, and Millikan gave him the notes for the purpose of preparing an excerpt. He was extremely surprised and crushed when the manuscript, not intended for public use, appeared in print in Science. Nobody is less inclined than he to raise doubts about Kohlhörster’s high merits. At his talk in Pasadena (before his departure for the scientists’ convention) he said verbatim: “Hats off to Kohlhörster.” Perhaps this information will serve toward al- lowing a milder judgment of his conduct. Respectfully and sincerely yours, Paul S. Epstein 348. To Michele Besso [Zurich,] Wednesday [11 August 1926][1] Dear Michele, Enclosed you’ll find the paper with the letter by Beck.[2] I want to abstain from giving an opinion on the paper because I’m not familiar with the investigation by Halpern.[3] But it is obviously particularly painful to use the quantum condition to- gether with the equations of motion here, because the validity of the latter appears to be irreconcilable with the validity of the former.[4] As regards the letter,[5] I note that it gives an idea of the most natural method. But it is questionable whether the equation has any reality left within it in the face of quanta. I vigorously doubt it. In contrast, the left-hand side of the equation surely contains a deeper truth. If the equation really deter- mines the behavior of the singularities, then a law describing this behavior would be founded far more deeply than by the aforementioned equation, which is non- uniform and merely phenomenologically justified.[6] The equation , Rik 1 2 -- - gikR – Tik = Rik 0= Rik gikfαβfαβ 1 2 -- - fiαfkβgαβ – =