l x i i I N T R O D U C T I O N T O V O L U M E 1 4 supervision of Max Born and James Franck. In it he criticized Einstein’s 1917 pa- per on the same subject, and argued that the assumption of a sharply directed radi- ation (“needle radiation”) is unnecessary in order to obtain Einstein’s results (i.e., equilibrium between Planck distributed radiation and the radiating/absorbing at- oms). The paper had been conceived under the spell of the BKS theory and before the Compton experiments had securely established the light quantum hypothesis. In his “Remark on Jordan’s Paper,” received on 22 January 1925, Einstein pointed out Jordan’s mistake (Einstein 1925o [Doc. 425]). Eventually, the Bothe and Geiger experiment verified the quantum collision the- ory of Compton and Debye, and the BKS theory had to be jettisoned. Bothe and Geiger announced their positive result in a short note in Die Naturwissenschaften, submitted on 18 April 1925 and published on 15 May 1925, and then in a long pa- per in Zeitschrift für Physik, which was received on 25 April 1925, all of them while Einstein was already in South America.[32] Einstein reported on the BKS the- ory and on the Bothe-Geiger experiment in his talk on 7 May 1925 in Rio de Janeiro titled “Remarks on the Current State of the Theory of Light” (Doc. 485). IX Shortly after his return from the Far East in March 1923, Einstein announced his resignation from the League of Nations’ International Committee on Intellectual Cooperation, or ICIC (Vol. 13, Doc. 447). He subsequently explained and defended this step, in light of the French-Belgian occupation of the Ruhr, writing that the League had discredited “the pacifist ideal” and was “a tool of those presently in power” (Docs. 10, 42). But not much later he began to doubt the wisdom of this decision. Might the res- ignation have been “inappropriate,” given its effect on “upright” members of the League (Docs. 49, 61)? In a statement published in June 1923, Einstein explained that he had taken the step “with inner reluctance” and that he hoped to be proven wrong by the League in the future (Einstein 1923p [Doc. 19]).[33] After his return to Berlin from exile in Leyden in late December 1923, he still appeared resolute not to collaborate with the organization (Doc. 186). He viewed the political situation with much pessimism, writing to the American physiologist Jacques Loeb that Europe “seemed destined to waste away due to the backwardness of its mentality.” Ascribing a great responsibility for this state of affairs to France, Einstein con- cluded that “no ray of hope is visible” (Doc. 187). However, following the victory of the left in the French parliamentary elections in May 1924, Einstein reflected that his resignation had been caused by “a moment