I N D E X 9 2 9 Drosue, M. P., 251n Drude, Paul electron theory of metals of, 169 equation for specific resistance of metals, 170 Drummond, Eric (1876–1951), liv, 389, 438 in- vites AE on Committee on Intellectual Coop- eration, 307, 308 AE accepts, 321–322 Drygalski, Erich von (1865–1949), 77n Du Bois, Henri (1863–1918), 184 Dualism of classical and quantum conceptions, 76 of gravitational and electromagnetic fields, 64 in physical theory, 730 of wave theory of light and quantum theory, 97 Duhamel, Georges (1884–1966), on having din- ner with AE, 275 Dunn, Gano (1879–1953), 721 invites AE to Columbia University, 724 Dutch-German eclipse expedition, 325n Eclipse, invitation to take part in 1923 expedi- tion, 829 Eddington, Arthur (1882–1944), xxxiv, xxxvi, xlviii, lxxiv, lxxv, 592n, 718, 729, 730, 790a, 843 recent theory of, 661 theory of AE on, 332, 388, 554, 698, 706, 874a, 888 beautiful but not true, 370 Haldane on, 62 Langevin on, 232–233 Zangger on, 114 theory of stellar structure, 251n Eggeling, Helmuth (1880–1925), AE on inven- tion by, 43 Ehrat, Jakob, 783a Ehrenfest, Anna (Galinka) (1910–1979), 294n, 805a, 806a Ehrenfest, Arthur (1862–?), 448n Ehrenfest, Ellen, 448n Ehrenfest, Emil (1865–?), 448n Ehrenfest, Hugo (1870–1942), 448n Ehrenfest, Otto (1872–?), 448n Ehrenfest, Paul (1880–1933), xxxiv, xxxv, xxxvii, xxxix, xli, lvii, lxxi, 123n, 132, 146, 177, 179, 209, 279, 289, 293, 300, 314, 379, 791a, 792a, 793a, 800a, 849, 852 AE on finances of, 177 impressed by, 368 invites to Leyden, AE declines, 26 needs his friendship, 448 on no one important to, 448 requests photos of sons, 448 requests plan for Leyden visit, 748 requests visit in spring, 142–143, 183–184 on royalties of from Methuen, 447 on visit of, 277 in Berlin, 368 Bohr, impressed by, 368 in Christiania, 58 on Collected Papers of Hamilton, 265–267 on discovery of adiabatic hypothesis, 511n– 512n on experiment on nature of light, 90, 106–108, 109, 116, 117–118, 125 on Hugo Ehrenfest’s visit, 447, 475 on Ioffe, 306 Langevin, sends greetings to, 303 on manuscript of Einstein and Ehrenfest 1922, 447, 475 on meeting brothers in Vienna, 447, 479–480 Ornstein, on aggressivity of, 184 on planned meeting on redshift, 142, 210 praised by French physicists, 274, 277 Sommerfeld on, 512n on son’s Down syndrome 448, 475, 480 on Stern-Gerlach experiment, 306–307 Ehrenfest, Paul, Jr. (1915–1939), 294n Ehrenfest, Tatiana (1905–1984), 58, 75, 294, 294n, 480 matriculates at University of Ley- den, 480 Ehrenfest, Wassily (1918–1933), 294n Down syndrome of, 448, 475, 480 treated in Erziehungsheim in Jena, 480 Ehrenfest-Afanassjewa, Tatiana (1876–1964), 28, 294, 448n, 748n, 805a brings Wassily to Jena, 480 on five-dimensional quantum theory, 134 Kagan, on manuscript of, 806a Ehrenfest-Schwab, Sophie, 448n Ehrenhaft, Felix (1879–1952), 814a requests copies of publications, 78 requests opinion on Kottler, 78–79