D O C U M E N T 1 6 J U L Y 1 9 2 5 3 7 will not assume leadership again until the overwhelming majority has come to see that yours is the only possible path. It won’t take long, under the pressure of cir- cumstances, until that point is reached. On the other hand, I do not at all understand why you want to resign from the board of the university. However, I suspect that you are also dissatisfied with the efforts of the rich American donors to shut out Europe.[2] But if there are no partic- ular reasons of this kind, specifically concerning the university, I urgently appeal to you not to resign from the board. Because, first, your influence there is perpetu- ally necessary and, second, because your simultaneous resignation from the board would create the impression that some sort of broges-feeling[3] might have contrib- uted to your resignation from the presidency. This must absolutely be avoided. In fact you are leaving that position because, in your opinion, there is no sufficiently certain and strong majority behind you on which you can base your actions. In the meantime, I ask you to consider this intermezzo as a tactical measure and as a means of recovery and gathering of new forces! Kind regards from your A. Einstein 16. To Albert Wigand[1] [Berlin,] 8 July 1925 Dear Colleague, I would like to inform you that Prof. Piccard in Brussels has completed with great precision those experiments on the accuracy of electric neutrality for ion-free matter.[2] The outcome was clearly negative at a precision that shows that a mass m exerts no electrostatic effect of the order of magnitude . My specula- tion about the geomagnetic forces therefore lacks any experimental foundation for the present. Your finding about the non-validity of Gauss’s law in the atmosphere cannot be reconciled with Piccard’s result, either.[3] Best regards, your A. Einstein e m κ =