universal ring sundial
Date: circa 1770
Inventory Number: 7158
Classification: Sundial
Dimensions:closed: 29.6 x 23.3 x 2.1 cm (11 5/8 x 9 3/16 x 13/16 in.)
open: 29.6 x 23.3 x 20.4 cm (11 5/8 x 9 3/16 x 8 1/16 in.)
DescriptionThis is a large universal ring dial with a nautical quadrant on the reverse. It is made of brass and silvered brass. The suspension ring is attached to a shackle that runs in two tracks around the meridian ring.
The equatorial ring is silvered and marked for the hours, I-XII, twice, every 2 minutes on the top of the ring and along the inside edge. The meridian ring is divided 90°-0°-90°-0°-90°, every 30'.
The solar declination scale on the silvered bridge is divided on one side by months with subdivisions every 2 days. The months are labeled in abbreviated English. "N" and "S" are marked at either end of the bridge. The slider is not silvered. On the reverse of the bridge, the solar declination is given in terms of degrees, 23 1/2°-0°-23 1/2°, with subdivisions to 30'. The zero point is marked "Æ" for equator. Across the frame, the declination scale is divided in terms of the zodiacal calendar, marked with zodiacal symbols and divided into 2° intervals. This side also has "N" and "S."
The reverse side of the instrument has a nautical quadrant divided 0°-90°, every 30'.
Signedon underside of equatorial ring: Cuthbertson & Champneys Amsterdam
FunctionLarge universal ring dials such as this example were favored by mariners for finding time at sea. They could also be used to find latitude by means of the altitude of the sun at noon. For this purpose, a nautical quadrant was included on the back of the instrument
ProvenanceJoseph Drecker, Aachen, Germany, before 1928 (no. 186); Frederik Casparus Wieder, Noordwijk, The Netherlands, 1928; D. P. Wheatland, Topsfield, MA, 1959; gift to CHSI, ca. 1987.