Hayyim Selig Slonimski (Hazas, 1810–1904) was a popular author, scientist, and inventor. He founded Ha-Zefirah, a Hebrew newspaper devoted mainly to popular science articles written by himself and a team of collaborators, adherents of the Haskalah. His initial acquaintance with science was derived from old Hebrew books, but later he also read scientific literature in German. Among Slonimski’s other works are Kokhva de-Shavit and Toledot ha-Shamayim, both on astronomy, the latter causing controversy, because it claims that there are errors in the Hebrew calendar. He also wrote Yesodei ha-Ibbur, on calculation. Slonimski coined new Hebrew terminology where necessary. Some of his mathematical and astronomical interpretations of obscure passages in the Mishnah found their way into editions of the Mishnah printed in Zhitomir. Slonimski was also an inventor, for example, a calculating machine, for which he was awarded a prize by the Russian Academy of Sciences (1844). Slonimski invented a method of simulataneous transmitting messages on a single wire, the electric telegraph (1859, 12 years before Stirnes and 15 years before Edison), but did not patent it (New York Herald Tribune, 23 August 1952 contains an article about the invention; qv, Krasnaya Zvezda, 19 Aug. 1952). Unlike other maskilim, Slonimski, due to his conservatism in religious matters and moderate outlook, was popular with all segments of the Jewish population.