3 0 4 D O C U M E N T 1 8 6 D E C E M B E R 1 9 2 3 See Doc. 97. Most likely the same lecture mentioned in Doc. 159. In a nonextant letter, Grossmann had reported to Einstein that Hans Albert obtained the highest grade in his class (see Docs. 190 and 207). In his ETH matriculation file, Hans Albert is reported to have passed (bestanden) the Vordiplomsprüfung on 23 October 1923, and his grades for the two- semester course in descriptive geometry given by Grossmann in the first year were 5’s (SzZuETH, Rektoratsarchiv). Grossmann’s children, Marcel Hans (1904–1986) and Elisabeth (1909–1986), were about the same age as Einstein’s sons, Hans Albert and Eduard. Grossmann had reprimanded Einstein in Doc. 97 for his decision to leave the International Com- mittee on Intellectual Cooperation. Einstein 1924d (Doc. 170) was presented to the PAW on 13 December 1923 and published on 15 January 1924. Ten years earlier, Einstein had turned to Grossmann for help when he encountered mathematical difficulties in his search for gravitational field equations (see Vol. 4, the editorial note, “Einstein on Gravitation and Relativity: The Collaboration with Marcel Grossmann,” pp. 294–301). Charles Edward St. John (1857–1935) was an astronomer at the Mount Wilson Observatory near Pasadena. For a historical discussion of the evolution of St. John’s views of the reality of the gravita- tional redshift, see Hentschel 1993. Grossmann had been involved in Einstein’s 1912 appointment at the ETH. After Einstein’s move to Berlin, he had made repeated attempts to lure him back to Zurich see Sauer 2014b, for further dis- cussion. Peter Debye, Hermann Weyl.