2 6 4 D O C U M E N T S 2 4 9 , 2 5 0 A P R I L 1 9 2 6 friends, because there are no rooms to be found. And at these friends’ place, staying in the same bedroom as the housewife. Ornstein is in Palestine.[12] What’s he doing over there? My wife will most likely stay in Moscow until the end of May. Tanitchka[13] is tackling “the economy” with the left hind foot, between lectures. I saw your light-corpuscle-tail-dismembering experiment in Naturwissen- schaften.[14] In case this experiment comes out differently from what the (error- free) application of wave theory of light requires—then, hats off![15] How are things with Albert?— And where is Margot?[16] Now forgive me for all my sins, give my sincere regards to your wife,[17] and answer[18] my questions without swearing! Galinka is delighting me enormously![19] She knows precisely what she wants. Warm regards, your Ehrenfest 249. To Hans Reichenbach [Berlin, 8 April 1926] Dear Mr. Reichenbach, You are completely right. It is wrong to think that “geometrization” is something essential.[1] It is only a kind of crutch for the discovery of numerical laws. Whether one links “geometrical” intuitions with a theory is an inessential private matter.[2] The essential thing with Weyl is that in addition to the invariance regarding trans- formations, he subjects the formulas to a new condition (“gauge invariance”).[3] This advantage is neutralized again by one being compelled to switch over to equa- tions of 4th order, which signifies a considerable increase in arbitrariness.[4] Best regards, your A. Einstein If I can do anything for you, do write me. 250. To Chaim Weizmann [Berlin,] 9 April 1926 Dear Mr. Weizmann, I was very pleased to hear that you intend, at least temporarily, to withdraw from the leadership of the Zionist Executive and to apply your energy in the service of