or Alfragán, an Arabian astronomer, who lived under the reign of the caliph Almamoun, and who, on account of his skill in calculation, was surnamed the Cal- He wrote an *Introduction to Astronomy*, which contains little that is original, being chiefly compiled from the *Almagest* of Ptolemy. He was also the author of a treatise on *Dials*, and of an account of the construction and use of the *Astrolabe*. These two pieces still remain in manuscript; but there have been three different Latin translations of his astronomical work published. The first, by Joannes Hispanensis, appeared at Ferrara in 1493, and was afterwards reprinted at Nuremberg in 1537, with a preface by Melanchthon. The second, by John Christianus, was published at Frankfort in 1590. The third, and the best, by Golius, professor of mathematics and oriental languages at Leyden, was published at Amsterdam in 1669, with the Arabic text, and notes by the translator, which are extremely curious; but these notes extend no farther than the ninth chapter, as the author did not live to complete this part of his undertaking. The work itself contains thirty short chapters.