2 3 0 D O C U M E N T S 2 2 0 , 2 2 1 M A R C H 1 9 2 6 220. From Hendrik A. Lorentz Haarlem, 14 March 1926 Dear Colleague, You will recall the conversation that we had a few months ago with Van Everdingen[1] about meteorology. We have now advanced to the point that a few meteorologists, namely the Committee for the International Scientific Bureau (whose chairman Mr. Delcambre[2] is in Paris and of which Van Everdingen is also a member), and, as I hope, the younger Bjerknes,[3] will meet with us on Monday[4] [10 o’clock in the morning] and Tuesday 29 and 30 March at the Paris Institute (of Luchaire).[5] By “us,” I mean you, Mrs. Curie,[6] and myself. I would be very pleased if you could come. Although we will probably accomplish only a little here, we must try to do something, given the importance of the matter. Warm regards, yours truly, H. A. Lorentz Things are going poorly with the League of Nations hopefully, we can still find a solution by the day after tomorrow.[7] I just[8] received your letter.[9] Of course, I am very sorry that you cannot come, but there’s no reason you can’t have Langevin[10] represent you.[11] [I mean on the 29th (meteorology). Regarding the 25th, Mr. Painlevé (who will preside) will have already written to you.] I’m counting on the fact that you will perhaps write him yourself. Tell him that he will be very welcome with us. The new experiment by Bothe is quite remarkable.[12] I still can’t get my bear- ings with matrix mechanics. 221. From Leo Szilard [1] Berlin, 14 March 1926 Dear Prof. A. Einstein, I’ve just heard that Mr. Grommer[2] looked for me in Dahlem, and I think that perhaps you want to get a better look at Rupp’s work, which I brought with me again on Saturday.—[3]