3 4 0 D O C U M E N T S 3 3 8 , 3 3 9 J U L Y 1 9 2 6 (Terminus) right near the cog railroad. I think you would like it, and the two of us would be very glad if you came. Hotel price without services, 11 fr. Anna was very kind to me I send her very special greetings. Greetings to Rosa’s “Bub” and your little ones, but especially to you, from your Albert 338. To Elsa Einstein Hotel Terminus, Montana Vermala [30 July 1926] Dear Else, I am very pleased that Dr. Mendel’s work has been successful. Otherwise, there is unfortunately little going well with you. In Geneva, it was again unspeak- ably boring. Thank goodness, over with. If only I had been a fiend and not re- ceived Magnes. Now, I had to telegraph London so he can’t twist anything. I was, in fact, so careful not to talk to him about the past wasn’t it clever that I refused to do so? I arrived here today Tete, too. Tidy, simple little inn. Warm regards, your Albert Ilse and Margot wrote me very nicely 339. From Auguste Piccard and Ernst Stahel Brussels, 30 July 1926 Dear Professor, We have the pleasure to inform you of the following results of the just completed measurements of our Michelson film. We drew the most probable sinusoidal curve, according to the least squares method, from the mean value of 96 usable balloon revolutions at 2,500 m altitude, on 21 June between 0:41 hours and 3:23 hours, Belgian summertime. This curve has an amplitude of 0.35 percent of an interference fringe width, with a probable error that is somewhat larger than this amplitude. Thus, we can say that the effect is smaller than about 0.6 percent, which, given an optical path of 280 cm and λ = 4357 Å, corresponds to an ether wind of 9 km per second. The photographic observations at noon failed. Visual observations around 11 o’clock in the morning at 4,500 m altitude also yielded no effect, with a precision limit of 1/10 of a fringe distance.