D O C U M E N T 1 4 2 J A N U A R Y 1 9 2 8 1 5 1 tion now is whether it will stop spreading soon enough. So far, the cardiac function seems to be withstanding the fever well. I ask you to keep this news to yourself for the time being. We all hope, of course, that Lorentz will recover his health. But it is VERY serious. He became a professor exactly fifty years ago today. In the event of an unfavorable development I will send you a short telegram. Your presence, even if only for two or three days would mean a lot, first for the De Haas family[5] and then, formally, for the university. ASSUMING YOU YOURSELF ARE HEALTHY!!!!! In that case I ask you to reply by telegram to say whether you are coming, and if you are, on which train. Sincerely, your Tanitschka is taking her “doctoral examination”[6] right now. The first part went well. The second (formal) part comes on Friday. She is therefore VERY interested that you have derived the dynamic motion equation from the gravitational field equation.[7] We have no offprint. Please send us two offprints! And I have no off- prints at all from the last three years! 142. To Han Sin Liau[1] Berlin, 28 January 1928 Dear Mr. Liau, According to my promise, I hereby answer your three questions:[2] 1/. The creation of an independent China is absolutely in the interest of all. All right-thinking Europeans wish this, mostly for the Chinese themselves. 2/. Given the uncertainty[3] prevailing in China, foreign states cannot be re- proached for seeking to protect their citizens who have settled in China. But they do not have a moral right to meddle in China’s internal development. 3/. It is a general duty to oppose acts of violence and terror, no matter by whom or through whom they are committed. However, in view of the unclear situation that prevails in China, it appears to be hard for a right-thinking person to support one party in an unambiguous and one-sided way. In my opinion, only a union of educated Chinese directed exclusively to the lib- eration and organization of the country could have a chance to succeed. Respectfully yours, A. Einstein