382 BIOGRAPHIES geometry. 1927, retirement from ETH. Einstein used Grossmann's class notes as a "Rettungsanker" to prepare for ETH examinations dedicated his 1905 doctoral dissertation to him paid tribute to him in Einstein 1955. Sources: Vierteljahrsschrift der Naturforschenden Gesellschaft in Zürich 81 (1936): 322-326 obituary by his classmate Louis Kollros, Verhandlungen der Schweizerischen Naturforschenden Gesellschaft 118 (1937): 325-329 Dictionary of Scientific Biography, vol. 5, pp. 554-555 Neue Deutsche Biographie, vol. 6, p. 159 correspondence with Einstein. Habicht, Johann Conrad b. 28 December 1876 in Schaffhausen d. 23 October 1958 in Schaffhausen Friend and life-long correspondent of Einstein. Son of a bank director in Schaffhausen. Attended Gymnasium in Schaffhausen. 1896-1897, studied philosophy at University of Zurich. 1897-ca. 1901, studied mathematics and physics at Universities of Munich and Berlin. 1901, met Einstein in Schaffhau- sen, where Einstein was tutoring at private school of a neighbor, Jakob Nüesch. 1901-1903, studied mathematics at University of Bern. 1903, joined an informal discussion group recently formed in Bern by Einstein and Moritz Solovine, known as "Akademie Olympia." 1904, University of Bern doctoral dissertation, "Die Steinerschen Kreisreihen," supervised by J. Graf. 1904- 1915, taught physics and mathematics at Protestant school in Schiers, canton of Graubünden. 1913, married Anna Kehlstadt, with whom he had four chil- dren. 1915-1948, teacher at Kantonsschule Schaffhausen, mainly in physics. 1935-1958. Director of the Schaffhausen Musikkollegium, in which he played the violin. Sources: Schaffhausen Genealogisches Register, SzS-Ar Bern Schriftenkontrolle, SzBe-Ar Schaffhauser Nachrichten, 29 October 1958. Haller, Friedrich Berchtold b. 12 October 1844 in Veltheim, canton of Aargau d. 11 January 1936 in Bern Einstein's patent office superior. Son of a Protestant minister. Received pri- mary instruction at home. Ca. 1859, entered second class of Gewerbeschule at Aargau Kantonsschule. 1862-1866, studied mechanical engineering at ETH. 1866-1872, worked for railroad construction firm in Olten, canton Solothurn.