COHN, BERTHOLD

COHN, BERTHOLD (1870–1930), German astronomer, mathematician, and historian. Cohn, who was born in Ravicz (now Poland), studied in Basle, Breslau, and Strasbourg. He was appointed astronomer at Strasbourg Observatory. Some of his astronomical publications addressed Gaussian mathematical methods; the theory of logarithms; tables on the beginning of twilight; the first visibility of the moon; determinations of the orbits of three comets; and the comparison of various star catalogues (1912). His first historical paper dealt with the structure of the Jewish calendar (in the Zeitschrift der Deutschen Morgenlaendischen Gesellschaft, 59 (1905), 622–4). In "Die Anfangsepoche des juedischen Kalenders," Cohn suggested that the total solar eclipse of June 6, 346 C.E. (4106), fixed the time of the original new moon (of the creation period) as the point for back-dating the Jewish calendar (Sitzungsberichte der Koeniglich-Preussischen Akademie der Wissenschaften, no. 10 (1914), 350–54). (Arthur Beer)