D O C . 3 6 M A Y 1 9 1 9 3 3 one sees how far away we still are from exact knowledge about the electromagnetic field. Your theory of the electr. field seems to me in any case equivalent to the con- ventional one. With best regards, yours truly, A. Einstein. 36. To Wander de Haas Berlin, 5 Haberland St., 9 May 1919 Dear de Haas, I am happy to have occasion to write you again, particularly so that I may con- gratulate you and your wife right away about the safe arrival of the latest little de Haas.[1] I should also not like to omit to report, in response to the kind question by our dear and esteemed Lorentz, that I am doing very well, even healthwise, despite the difficult circumstances. In July, I shall be back in Zurich to lecture on relativity. It is the second half of a course that I began there this winter.[2] In Zurich a quite good experimenter (Mr. Beck) repeated our measurements on the angular momen- tum of ferromagnetic material and found only half the theoretically anticipated effect [3] I think you know about this already. I still have your tiny rod shaft in safe- keeping—a remarkable little curiosity [4] during my last visit in Holland I forgot to tell you about it.[5] Now to business. My collaborators and I were very pleased that Mr. Lorentz is very willing to help us.[6] During the war years, such an undertaking would have not only been dangerous but simply impossible, since every last piece of documentary material would have been inaccessible.[7] Now our enterprise should be devoted almost exclusively to 〈educating〉 enlightening local public opin- ion. We want to try to obtain the incriminating material through our neutral associ- ates and try to verify the same against documents here. It is intended that the find- ings be publicized. We originally wanted to approach the government with our petition only after we had conferred with our neutral associates abroad so as to come forward with greater weight and to have better prospects of making the local documents available to us.[8] The present moment is not favorable, partly because of aroused political passions, partly because our efforts could be falsely interpreted as long as the conditions for peace are not fixed.[9] We must avoid the appearance on either side that we were concerned about any sort of political goal, in the usual sense of the word. That is why I did not send a telegram but rather chose the slower route by letter.[10] With the enormous abundance of material, it cannot be our goal to follow up the crimes of any given individuals. We must, in my view, rather restrict ourselves to