2 7 4 D O C U M E N T S 2 5 9 – 2 6 1 A P R I L 1 9 2 6 259. To Emil Rupp [Berlin,] 18 April 1926 Dear Mr. Rupp, I am very pleased to hear that you want to conduct the research with me.[1] How- ever, I would like to ask you to inform me regarding the proposed set-up and ex- periments, as well as the results, since there various aspects have occurred to me that would have to be taken into account. If it weren’t for the Heidelberg laboratory,[2] I would come there, because the results will be quite important for the theory of radiation. Please write back to me with more details soon. Your A. Einstein 260. To Ralph E. Zuar [Berlin, after 18 April 1926][1] Dear Sir, I have no great opinion of the reliability of Miller’s results. ¢Also² The experi- ments by Tomaschek ¢learn² have reduced the likelihood of the correctness of Miller’s views ¢appear even slighter than² even more.[2] But now is not the time for a discussion of this issue. The completion of such experiments as correspond fully to Miller’s method must be awaited.[3] 261. To Erwin Schrödinger [Berlin,] 22 April 1926 Dear Colleague, I see just now from your first paper[1] that you really did base the equation on the consideration that corresponds to the addition theorem for independent sys- tems. Therefore, my letter[2] was superfluous. As concerns your paper on gas theory,[3] I do not see any difference in its foundation compared to mine. For, you also characterize the state (equal probability) by the sum of the numbers , where the numbers , etc. have the same meaning as with mine.[4] div gradψ konst( E Φ)ψ – + 0 = n1, n2, n3 .... n1, n2