1 5 8 D O C U M E N T S 1 3 7 , 1 3 8 D E C E M B E R 1 9 2 5 137. Greetings to the Federation of Jewish Student Associations in Germany[1] [Berlin,] 25 December 1925 To the Federation of Jewish Student Associations in Germany: I wish your conference the greatest success. I would like very much to be there in person, but am unfortunately ¢forced² prevented from attending by urgent work. I will always do my utmost to promote your objectives. A. E. 138. To Michele Besso [Berlin,] 25 December 1925 Dear Michele, Cordial New Year’s greetings. The Treaty of Locarno is the best thing that has happened in the meantime that was a real joy for me.[1] Politicians are more rea- sonable nowadays than professors.[2] Are you really going to Jerusalem? Our Jews are doing much down there and quarreling as always. I’m quite involved with that, because—as you know—I have become a Jewish saint.[3] I also think that Miller’s experiments are based on temperature errors.[4] I didn’t take them seriously for a single moment. I unfortunately had to scrap my research along Eddington’s lines again. Overall, I am now convinced that unfortunately nothing can be done with the Weyl-Eddington complex of ideas.[5] I consider the equation the best that we have to date.[6] There are 9 equations for the 14 quantities & .[7] New calculations seem to suggest that these equations deliver the motions of electrons.[8] But it seems doubtful whether quanta have a place in it. The most interesting thing that theory has produced recently is the Heisenberg- Born-Jordan theory of quantum states.[9] Such a magic formula, in which infinite determinants (matrices) take the place of Cartesian coordinates! It is sufficiently protected against refutation through its supreme ingenuity and complicated nature. I’m glad that you are having such a good time with your little grandchildren.[10] Hopefully we’ll be seeing each other in summertime I am certainly coming to Switzerland, to go to the mountains with Tete somehow.[11] He’s been wanting to do that for so long, because he isn’t a sailing nut like his old man. Warm regards to you, Anna and Vero[12] from your Albert Rik 1 4 -- - gikR – Tik electromagnetic –= gμν ϕμ