D O C U M E N T 1 0 6 N O V E M B E R 1 9 2 5 1 2 7 what I can to prevent your intended marriage to a girl whom, per se, I have not the least thing against.[6] I merely fear for you and her and your future children. I am convinced that on the girl’s side there are such unfavorable hereditary factors, pri- marily from the mother’s side[7] (the father is reportedly also not a particularly good specimen) that children would be a concern.[8] Add to that the age difference. It is even worse than it was in my case.[9] What I have suffered because of that, and how seriously you would suffer! In 10 years, you will still be a young vigorous man and she will no longer satisfy you. You will experience your marriage as an intol- erable fetter she will become terribly jealous and you—I know you don’t believe me—that is the worst part of the whole thing. However, I must warn you and do everything possible to hold you back. Therefore, I have also written to Anschütz to assist me in this as a long-time good friend.[10] For experience has shown that it is easier for a young man of your kind[11] to express himself with an outsider. Certainly do that. What you write about Kiel is nonsense. If that’s the right place for you, go there, if not, then don’t. I will be delighted to have you nearby. You should absolutely not let any defiance arise toward me. Because I am not trying to attain anything from you and wish even less to expect or demand anything from you. I only want to save you from making a serious mistake, to the best of my ability. The main thing is for you to always be totally honest with me. There is no stu- pidity that would be so great that it could alienate me from you. Remember that. With warm regards, your Papa 106. To George Y. Rainich [Berlin,] 13 November 1925 Dear Colleague, I am glad that you drew my attention to your very fine and insightful paper.[1] What I have been envisioning during the past few years is the endeavor to find a conception according to which the gravitational field and the electromagnetic field appear as components of one and the same mathematical construct, and in which the field equations likewise appear logically unified. This is evidently not the case with the equations Rik 1 2 -- - gikR¹ – © § · Eik) ( + 0, =