German rabbi and author; born Feb. 10, 1834, in Holzhausen, near Marburg in Hessen; died at Bonn Sept. 19, 1902. He was educated at the universities of Marburg and Rostock (Ph.D. 1865). When thirty-one years old he accepted a call as rabbi from the community of the district synagogue of Memel. While in this office he took great interest in the condition of his oppressed brethren in Russia, and thus created for himself a wide sphere of activity. In 1898, after thirty-three years of service, he resigned and retired as professor emeritus to Bonn. Rülf was the author of: "Meine Reise nach Kowno" (1869); "Der Einheitsgedanke als Fundamentalbegriff," etc. (1880); "Drei Tage in Jüdisch-Russland" (1882); "Aruchas Bas-Ammi" (1883); "Wissenschaft des Weltgedankens" and "Wissenschaft der Gedankenwelt, System einer Neuen Metaphysik" (2 vols., 1888); "Wissenschaft der Krafteinheit" (1893); "Das Erbrecht als Erbübel" (1893); "Wissenschaft der Geisteseinheit" (1898); "Wissenschaft der Gotteseinheit" (1903). From 1872 until his departure from Memel, Rülf was editor-in-chief of the "Memeler Dampfboot," a daily political journal. He wrote also for various Jewish papers.