Combination Portable Horizontal Sundial and Perpetual Calendar, Perpetual Box-Almanack and Geographical Mirror

Combination Portable Horizontal Sundial and Perpetual Calendar, Perpetual Box-Almanack and Geographical Mirror

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This English horizontal sundial and perpetual calendar is stored in a round leather case. The case is hinged, has a brass hook for fastening, and is lined with light blue satin and coarse green felt. The instrument has a wooden container with removable lid. Inside the container is a sundial with compass affixed to a wooden base that lifts out of the case. The wooden base is painted red around the edge and a decorative pattern of blue, black, and gold on the top. The hour ring is silvered brass with a blade gnomon that folds up. The hour ring is calibrated from VIII to XII to IV by hours, subdivided for half-hours. Underneath the hour ring is a compass with glass cover. The compass rose has sixteen lettered points. The rose is colored with red ink, black stripes, and a multicolored pattern. A fleur de lis is at North. The outside of the compass is calibrated from 0 to 90 by tens four times (e.g. 0 to 90 down to 0 up to 90 and then down to 0). The wooden container is covered with printed paper and shellac. Ivory dials (2.7 cm in diameter) are nailed and screwed to the center of the top and the bottom. The top of the container contains a perpetual calendar for the years 1793 to 1832--NMAH*330846, a flyer of instructions for this instrument, explains that “1792” appears under dominical letter G in error. (“1837”also appears under A in error, as there was no room to include the years 1833-1836.) The ivory dial is marked with dominical letters and days of the month. The dial turns so that it may be set against a round chart of months and days of the week. A chart outside this ring gives the dominical letters for the years 1792 to 1832. The outermost chart tells the number of days in each month, the first day of each season, and saints’ days and other holidays. Most notable is the birthday, coronation, accession, and procession of George III, as well as the birthday of his wife, Charlotte. Perhaps the maker was Catholic, since the restoration of Charles II (29 May 1660) is also marked. An hour ring is on the edge.
Currently not on view
Object Name
Date made
ca 1800
Saunders, Thomas
Saunders, Thomas
overall: 4.9 cm x 9.1 cm x 8.5 cm; 1 15/16 in x 3 19/32 in x 3 11/32 in
ID Number
accession number
catalog number
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Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History
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