细节
JOHAN MARTIN, Augsburg
A silver pocket universal equinoctial dial, the brass hour ring with applied silver scale divided 3-12-1-9 adjusted for latitude by needle operated cam divided 30°-65°, the compass with blued-steel needle and engraved silvered-dial the horizontal plate engraved with scrolls and Gradus Poli, in hinged case the exterior engraved with the latitudes for approximately forty five cities and signed Johan Martin in Augspurg 48, within wreaths -- 1¾in.(4.5cm.)diam.,(lacks gnomon) circa 1700
See colour plate
