DIGGES, Leonard (c.1515-c.1559). A Prognostication everlasting of ryght good effecte. London: Thomas Gemini, 1556.

The Harrison Horblit copy of a very rare work: the only 16th-century copy of Leonard Digges's Prognostication to appear in the auction records of RBH for the past 50 years. Leonard Digges was "an important member of the first generation of English mathematical authors to publish in the vernacular" (ODNB). The earliest surviving edition of this almanac is dated 1555, though in that work Digges refers to an even earlier version from 1553. Digges's Prognostication was innovative in its purpose of being "everlasting," i.e. useful for more than a single year. He not only provides calendrical tables, but also basic rules for predicting the weather and determining times for planting, grafting, and blood-letting. His preface is a charming defense of recreational mathematics and against the charges of vanity and impiety, to quote: "The ingenious learned, and well experienced circumspect student mathematical receiveth dayly in his witty practises more pleasant joye of mind than all thy goodes (how rich soever thou be) can at any tyme purchase" (fol. [1]r). Digges provides several diagrams of the geocentric system and of the relative sizes of the planets. ESTC S116106. Exhibited: "The Heavens Revealed," Chapin Library, Williams College, 2003.

Quarto (204 x 140mm). Woodcut of zodiacal man on title partially hand-colored, woodcuts and diagrams in text including a repeated geocentric depiction of the cosmos, woodcut initials (upper outer corner of first 5 leaves with repaired losses affecting the last letter of title and two other letters, a few diagrams shaved or bound close, mild soiling). Recent calf to style by Bernard Middleton. Clamshell box. Provenance: few instances of early marginalia, including an update for the years 1633-1641 on the table for calculating prime and epact (functions of the lunar cycle) – Harrison D. Horblit (his sale, 16 February 1994, lot 13).