466 DOCUMENTS 396, 397 MAY 1912 teilte mir mit, dass er sich zu meinen Bewegungsgleichungen des materiellen Punktes im Schwerefeld "bekehrt" hat.[8] Mit den besten Grüssen verbleibe ich Ihr ganz ergebener A. Einstein. ALS (Siebertz family, Munich). [23 558]. [1]The manuscript of Einstein 1912f (Vol. 4, Doc. 5), submitted six days earlier with Doc. 392. [2]Planck's "second quantum theory" is based on the assumption that absorption of radia- tion takes places continuously, whereas the emission process is quantized. One of its conse- quences is the occurrence of a term representing a zero-point energy in the mean energy of an oscillator in a radiation field. See Planck 1911a, 1911b, 1912 see also Kuhn 1978, chap. 10, for a historical discussion. [3]In Einstein 1912f (Vol. 4, Doc. 5), Einstein decides for the latter possibility in the case of photochemical decomposition. [4]"photochemischen" should be "photoelektrischen." [5]Arnold Sommerfeld's theory for the photoelectric effect, first published as Sommerfeld 1911b, was based on the principle of energy accumulation by atoms. See Doc. 197 for Ein- stein's comments see also Wheaton 1983, pp. 180-184, for a historical discussion. [6]Paul Ehrenfest visited Prague the last week of February (see Docs. 357, note 3, and 367, note 1). [7]The equivalence of inertial and gravitational mass was a key aspect of Einstein's theory of gravitation as expounded in Einstein 1912c, 1912d (Vol. 4, Docs. 3 and 4). See also Vol. 4, the editorial note, "Einstein on Gravitation and Relativity: The Static Field," for a discussion. [8]Max Abraham see Doc. 343, note 3, for more on the discussion of gravitation between Einstein and Abraham. 396. To Marian von Smoluchowski [Prague, 20 May 1912] Jederzeit herzlich willkommen wann Ankunft Einstein. TGM (P1CJ, 9414 III, p. 194). [20 601]. The telegram is addressed to "Professor Smoluchow- ski Univeritaet Lemberg." 397. To Marian von Smoluchowski Prag. 20. V. [1912] Hoch geehrter Herr Kollege! Ich telegraphierte Ihnen soeben,[1] weil mir siedend heiss eingefallen war, dass Ihren Brief noch nicht beantwortet habe Ich darf mir nicht gestatten, Sie mit Ihrer Frau Gemahlin[2] zu mir einzuladen, weil wir dazu nicht hinreichend