LÖWINSOHN, JACOB MORDECAI BEN JUDAH LÖB:
Russo-Polish scholar and journalist; born in Grodno 1832; died in Warsaw Feb. 13, 1878. A son of the rabbi of Grodno, he was trained in Talmud, and then studied Russian, German, Polish, and French, which he mastered in a very short time. Thus equipped he entered upon a journalisticcareer. He published numerous articles in Russian papers, and when, in 1862, Daniel Neufeldt founded the Jutrzenka, Löwinsohn became an active collaborator on it, always defending the interests of his coreligionists. He was a great controversialist, and had heated discussions with R. Hirsch Kalischer in "Ha-Maggid," and with L. J. Shapiro in the "Jutrzenka."
He settled in Serhei, government of Suwalki, where he made the acquaintance of David Gordon, editor of "Ha-Maggid," and Rabbi Ḥayyim Fillippower. About 1868 he passed his examination at the Rabbinical Seminary of Wilna, where he was ordained rabbi; but he never accepted a rabbinate.
Of his first work, "Ha-Adam be-Ẓelem Elohim" (Königsberg, 1855), only a limited number of copies were printed, which he distributed among his friends. His numerous articles and essays on Jewish literature and science he published under the nom de plume 
.
- L. J. Shapiro, in Gan Peraḥim, pp. 63-65, Warsaw, 1890;
- Shapiro and Gordon, in Ha-Maggid, 1878, No. 10, p. 80.
