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(SCIENCES) - Eliezer Beilin. Sepher Ivronoth [astronomy and calculations of intercalation and the Jewish calendar] Title within architectural arch featuring Moses and Aaron, with cherubs flanking a zodiac sphere. Numerous mathematical tables, spherical charts and illustrations. Woodcut illustrations of hand palms on ff. 23v. and 24r. Leaf 25 with 2-piece volvelle affixed on recto and 3-piece volvelle on verso. Leaf 28 with 3-piece volvelle affixed on recto and 3-piece volvelle on verso. Single sphere tipped between ff.36v and 37r. A rare copy, complete with all volvelles. ff. (2), 40. Browned. Modern boards. Sm. 4to. Vinograd, Offenbach 63. Offenbach: Israel ben Moses 1722 A Rare Copy, Complete With All Volvelles, Fully Assembled, in Their Original State and in Fine Condition. This edition is particularly attractive, with fine illustrations and volvelles necessary for calculations. A volvelle, or wheel chart is a type of slide chart, a paper construction with rotating parts. It is considered an early example of a paper analog computer. The Jewish calendar is lunisolar - while the months are reckoned by the moon, the years pass based upon the sun. In order to keep the two systems in sync with each other in accordance with Jewish law, astronomic and Halachic expertise is required. Sepher Ibronoth was prepared as a manual “to help an individual fulfill the commandments.” See A. J. Karp, From the Ends of the Earth: Judaic Treasures of the Library of Congress (1991) pp. 197-8.