animated by a desire for truth either to overcome these doubts and become settled in the early belief to which he had been brought up, or unsparingly to expose the false elements in Jewish tradition. Joseph Delmedigo was as little formed to be a martyr to his convictions as Leo Modena, the latter by reason of fickleness, the former, of insincerity. With doubt in his heart he returned to his home in Candia, and gave offense by his free mode of thought, especially by his preference for secular knowledge. He made enemies, who are said to have persecuted him, and was obliged to leave his native land. Then began a migratory life, which drove him from city to city, like his model Ibn-Ezra. Like him, he made friends with the Karaites wherever he met them, and they thronged to his presence. At Cairo Delmedigo celebrated a complete triumph with his mathematical knowledge, when an old Mahometan teacher of mathematics, Ali Ibn-Rahmadan, challenged him, a youth, to a public combat, in which Ali was beaten. The victorious combatant was magnanimous enough to show honor to Ali before the world. Instead of betaking himself to Palestine as he had intended, Delmedigo traveled to Constantinople; here also he attached himself to the circle of the Karaites, and at last passed through Wallachia and Moldavia to Poland. There, mathematics procuring him no bread, he practiced medicine, of which, however, he had learnt more from books than by the bedside of patients. In Poland he passed for a great physician, and was taken into the service of Prince Radziwill, in Wilna (about 1619-1620). Here, through the excessive attention given to the Talmud, general culture was forsaken, but youths and men eager for learning, especially Karaites, thronged to Delmedigo to slake their thirst for knowledge. A half-crazed Karaite, Serach ben Nathan of Trok, who had an inclination to Rabbinical Judaism, in order to show his extensive knowledge, with mock humility laid before him a number of important questions, which Delmedigo was to answer offhand, and sent him a sable fur for the Polish winter.