Typed letter signed ("A. Einstein").
4to. 1 page. In German. On blindstamped headed stationery.
€ 12.000,00
To the Hungarian-born physicist Cornelius Lanczos (1893-1974) at Purdue University, Lafyette, Indiana, about Lanczos's wave tensor, pointing out that it is indeed invariant in special-relativistic terms, but not the way in which it is constituted from individual waves of different frequencies; adding that his own research on complex space is not yet finished: "Nun noch eine Bemerkung über Ihren Wellen-Tensor: Es ist zwar richtig, dass dieser als Ganzes genommen spezial-relativistisch invariant ist, nicht aber die Art und Weise wie er aus Einzelwellen verschiedener Frequenz konstituiert ist [...] Meine Untersuchungen über den komplexen Raum sind noch nicht fertig".
Einstein further discusses his suffering from "bilious attacks", along with the challenges theoretical physicists face in finding defence work, and advises Lanczos to remain at Purdue University, as getting a job at the Institute for Advanced Study or elsewhere might prove difficult due to the lack of money there, compounded by xenophobia: "Ich glaube aber, dass Leute, die vorwiegend theoretisch gearbeitet haben, nicht so viel begehrt sind, besonders wenn noch die Xenophobie in Frage kommt".
Einstein's remarks about defence work are poignant: although the Einstein-Szilard letter to F. D. Roosevelt on 2 August 1939 effectively launched the Manhattan Project to construct an atomic bomb, he was himself denied clearance to work on it in July 1940, in part because of his pacifist views. In June 1943 he was, however, reported to be advising the Ordnance Bureau of the U.S. Navy on the theory of explosives.
Small tear to left margin.