in the pre-Haskalah period, the greatest Talmudists deemed it a sacred duty to perfect themselves in some branch of secular science.  When, in 1710, a terrible plague broke out in his native town, Rabbi Jonathan of Risenci (Grodno) vowed that, “if he were spared, he would disseminate a knowledge of astronomy among his countrymen.”  To fulfil the vow he went to Germany (1725), where, though blind, he devoted himself assiduously first to the acquisition of astronomy, then to writing on it.[40] Baruch Yavan of Volhynia, who more than any one exposed the impostures of Jacob Frank, “spoke and wrote Hebrew, Polish, German, and probably French,” and his accomplishments and address won him the admiration of Count Bruehl, the virtual ruler of Poland, and the favor of the highest officials at St. Petersburg.  His associate in the righteous fight, Bima Speir of Mohilev, was also possessed of a thorough command of the language of Russia, and was well posted in its literature, history, and politics.  The Pinczovs, descendants of Rabbi Polack, connected with the most eminent rabbinical families, and themselves famous for piety and erudition, produced many works on mathematics and philosophy.  Mendelssohn’s translation of the Pentateuch was at first hailed with joy, and was recommended by the most zealous rabbis.  Doctor Hurwitz of Vilna did not hesitate to dedicate his ’Ammude Bet Yehudah to Wessely, who was more popular in Russo-Poland than in Germany.  The whole edition of his Yen Lebanon, which fell flat in the latter country, though offered gratis, was sold when introduced into the former.[41] Joseph Pesseles’ correspondence concerning Dubno, with David Friedlaender, the disciple of Mendelssohn (1773), proves the high esteem in which the liberal-minded savants of Berlin were held in Russia.  The rabbis of Brest, Slutsk, and Lublin gave laudatory recommendations to Judah Loeb Margolioth’s popular works of natural science, which form a little encyclopedia by themselves.  Margolioth was the grandson of Mordecai Jaffe, himself rabbi successively at Busnov, Szebrszyn, Polotsk, Lesla, and Frankfort-on-the-Oder (d. 1811).  The writings of Baruch Schick of Shklov, referred to above, were accorded the same welcome.  His translation of Euclid and his treatises on trigonometry, astronomy (’Ammude ha-Shamayim), and anatomy (Tiferet Adam) won the admiration of rabbis as well as laymen.  Epitaphs of the day contain the statement that the deceased was not only “at home in all the chambers of the Torah,” but also in “philosophy and the seven sciences.”  And this, exaggerated though it may be, must be seen to contain a kernel of the truth, when we recall that among Maimon’s intimate friends was the rabbi of Kletzk, Lithuania; that in the humble dwelling of his father there were works on historical, astronomical, and philosophical subjects; that the chief rabbi of a neighboring town, Rabbi Samson of Slonim, who, according to Fuenn, “had in his youth lived for a while in Germany, learned