452 DOCUMENT 385 APRIL 1912 and an emission theory such as Ritz's is discussed. Ehrenfest points out that Ritz's theory does not predict a transverse Doppler effect, in contrast to the theory of relativity (see Einstein 1905r [Vol. 2, Doc. 23], §7, for Einstein's first discussion of this effect). An entry on the sec- ond-order Doppler effect in Einstein's "Scratch Notebook" (Vol. 3, Appendix A), [p. 21], may refer to the discusion with Ehrenfest. Ritz's theory is also discussed in a manuscript by Ein- stein on electrodynamics and relativity theory (see Vol. 4, Doc. 1). [5]Johannes Stark. He had first studied the Doppler effect in the light emitted by canal rays (Stark 1906). See also Doc. 125, note 5, for more on his later work in this field. [6]A paper by Michael Frank, published as Frank, M. 1912 (see Doc. 380). [7]In Doc. 380 Ehrenfest had tried to generalize Einstein's work on photochemical decom- position (Einstein 1912b [Vol. 4, Doc. 2]) to include the region of higher radiation energy-den- sity. [8]The proofs of Einstein 1912c and 1912d (Vol. 4, Docs. 3 and 4), which were both pub- lished 23 May. [9]Einstein wrote him three weeks earlier in response to a request for recommendations for the Debye vacancy at the University of Zurich (see Doc. 381). Kleiner had already expressed his unequivocal opposition when Ehrenfest visited Zurich (see Doc. 366, note 13). [10]More than a month earlier Einstein had encouraged Pierre Weiss to assist Ehrenfest in obtaining an academic appointment (see Doc. 369). [11]Einstein earlier characterized Ehrenfest as a fanatical dissident (see Doc. 366). One of Einstein's colleagues at the German University argued that the probability of Ehrenfest receiv- ing an appointment in Prague was equal to zero unless he accepted formal affiliation with a religious community recognized by the state (see Anton Lampa to Paul Ehrenfest, 2 May 1912, NeLR, Ehrenfest Archive, Scientific Correspondence, ESC:7, 32). Ehrenfest himself forceful- ly conceded the point: "absolutely impossible" ("absolut ausgeschlossen") (see Paul Ehrenfest to H. A. Lorentz, 19 May 1912, NeHR, Archief H. A. Lorentz). [12]Daughters Tatiana and Anna. [13]While under consideration for an appointment at the German University at the end of 1910, Einstein had bowed to the religious requirement of the Austrian bureaucracy by regis- tering as Jewish in spite of his dissident status in Switzerland (see Doc. 238, note 1). [14]Tatiana Ehrenfest. [15]Einstein had a controversy with Walther Nernst on a proof of the latter's heat theorem. See Doc. 364, note 6 for more details. [16]Perhaps in a conversation Einstein had had with Nernst in Berlin. [17]Marian von Smoluchowski. [18]This postscript is written on the verso of the envelope, the recto and verso of which bear a number of soot smudges. Einstein complained a year earlier about Prague's sooty air (see Doc. 265). 385. To Emil Warburg Prague, 25 April 1912. Einstein writes of Warburg's "photochemical laboratory" ("photochemische Werkstatt") in der das zur Wirklichkeit wird, was ich schon seit Jahren in unbestimm- ten Umrissen träumte. Ich zweifle nicht daran, dass Ihnen die begonnene schwierige Untersu- chung noch vollends gelingen wird,[1] und dass Sie den Mechanismus Ihrer Reaktion klar legen werden. Abgesehen von dem, was wir besprochen ha- ben,[2] ist auch die Temperaturabhängigheit der Reaktion O2 + O = O3 von ho-