Important English silver made for the German market Circa 1710

Silver pair cased verge pocket watch  
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An extremely fine and important English, silver, pair-cased pocket watch, made for the German market, circa 1710. The outer case with manual perpetual calendar, indicates the zodiac and saints days, the seasons, religious festivals, sunrise and sunset and the length of daylight hours.

Outer case signed with master mark WS beneath a crown, square hinge, the bezel engraved with the months and their respective number of days, the back engraved with bands and segments containing the signs of the zodiac and their respective symbols, named saints days and their respective dates, start and finish of religious festivals and the seasons, calculation tables, the centre with two revolving discs for calculating the length of the daylight hours, sunrise and sunset and future dates.

Inner case signed with master mark IW, polished, deep back, shuttered winding hole, split bezel, loose ring pendant. Champlevé-silver dial, radial Roman numerals, outer minute track, Arabic five minute numerals, the centre with signature cartouches. Blued steel beetle and poker hands. A gilt full plate movement, divided Egyptian pillars with pierced foliate galleries, fusee with chain, verge escapement, three-arm steel balance, flat balance spring, finely pierced and engraved winged balance cock, silver regulation disc. Dial and movement signed.
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Diameter: 57 mm
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Signed: John Bushman  London
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The outer case, which is original to this watch is truly exceptional in its complication and execution. Very few watches from the late 17th and very early 18th centuries with this level of sophisticated mathematical information have survived and the present watch is in fine condition and complete. The engraving of the case would have been an achievement in itself and would have required detailed preparatory drawings to be given to the engraver. The functions of the Calendarium Perpetuum include Months and their number of days. Pictorial zodiac symbols and their written symbols. Saints days and their dates. Commencement and end dates of religious festivals. Commencement and end dates of the four seasons. Length of Daylight hours. Times of sunrise and sunset. John Bushman (also Buschman or Buschmann) A fine maker, he was born in 1661, a German watchmaker. Married in December 1690, then aged 29, a bachelor of the parish of St. Margaret, Westminster, to Mary Wyatt, 23, spinster, at Christ Church, London (as Johannes Bushman). Made a brother of the Clockmakers Company in 1692 and an Assistant in 1720. He is believed to have worked until 1725.