A RARE DUTCH SILVER-COLOURED METAL POCKET PERPETUAL CALENDARANONYMOUS, CIRCA 1700The dial with revolving disc incorporating six annotated apertures, the outer two for setting the zodiac and corresponding month of the year which then reveals the length of the day and night along with the time of sunrise and sunset to the inner four, the outer track engraved PERPETUUM CALENDARIUM and Hemels, Feiken, the reverse with another revolving disc engraved with a panel inscribed with the days of the week together with their respective symbols in vertical columns over a pierced sector revealing dates of the month over seven days, the disc can be turned to synchronise dates over a week for any given month, the upper margin engraved with a landscape view of a village within repeating leaf border and the outer edge of the disc with rope twist decoration.Diameter 4.4cm (1.75ins).Although the origins of the design of the present lot are not obvious, the earliest examples (mostly brass) appear to be German-made and date to the sixteenth century. From this it may be appropriate to speculate that the design was developed in one of the major horological centres, such as Augsburg or Nuremburg, alongside high Renaissance timepieces, sundials and other astronomical instruments.