640 BIOGRAPHIES Laub, Jakob Johann b. 7 February 1882 in Rzeszöw, Austrian Empire (now Poland) d. 22 April 1962 in Fribourg, Switzerland Einstein's first collaborator in physics. Son of parents of independent means. Ca. 1892, began secondary schooling at the Gymnasium in Rzeszöw. 1901, began studies in mathematics, theoretical physics, philosophy, and psycho- physics at the Universities of Cracow and Vienna. 1902-1905, studied math- ematics and physics at the University of Göttingen. 1905, began studies at the University of Würzburg urged by Wilhelm Wien to hold first colloquium on Einstein's electrodynamics of moving bodies. 1906, completed dissertation on secondary cathode rays with Wien. 1907, received his doctorate from the University of Würzburg. 1907-1909, remained in Würzburg to work with Wien. 1908, came to Bern for about six weeks to collaborate with Einstein on two papers (Vol. 2, Docs. 51 and 52). 1909, became Assistent to Philipp Lenard at the University of Heidelberg. 1911, married Ruth Wendt, with whom he had one child appointed to position as professor of Physical Geog- raphy at the University of La Plata, Argentina. 1913-1914, spent three months in Zurich during Argentine summer vacation auditing Einstein's course in electromagnetism and working in the Physics Institute of the ETH. 1914-1920, held chair of Theoretical Mechanics and was Director of the Physics Department at the Teachers College, Buenos Aires. 1915, became an Argentine citizen. 1916, published textbook on analytic mechanics in Span- ish. 1917-1919, held position of Professor of Physical Geography, University of Buenos Aires. 1920-1939, served as vice-consul to various Argentine con- sulates in Germany and Switzerland. 1928, served as private secretary to the Argentine foreign minister divorced his wife. 1939-1945, returned to Argen- tina, where he worked in the Foreign Ministry. 1945, visited Einstein a last time in Princeton. 1946, retired from Argentine diplomatic service. 1947- 1953, served as Assistent in the Physics Institute, University of Fribourg. 1953-1962, was befriended by Carl Seelig, who obtained transcriptions from him of Einstein letters and was able to draw on Laub's accounts of the last years of Einstein in Bern for his biographies Sources: His letters to Carl Seelig, SzSE Bibliothek Pyenson 1985 ar- ticles in Neue Deutsche Biographie. Löwenthal, Elsa, nee Einstein b. 18 January 1876 in Hechingen, Germany d. 20 December 1936 in Princeton, New Jersey Cousin and second wife of Einstein daughter of Rudolf, a textile manufac-