English Calendar Medal

English Calendar Medal

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This instrument consists of two metal discs that fit into opposite sides a larger metal disc that has raised edges. The three discs are pivoted at the center. Around the rim of one smaller disc, going clockwise, are the digits from 1 to 31. This disc has the inscription: DAY of the MONTH FOR EVER. Around the rim of the larger disc on this side, also arranged clockwise, are letters corresponding to days of the week (e.g. [one dot],S, M, T, W, T, F, S, [two dots], S, M, T, W, T, F, S, [three dots], S, M, T, W, T, F, S [four dots], S, M, T, W, T, F, S.
On the reverse side, the inner ring is inscribed: MOON’S AGE PHASES & SOUTHING. It then has a ring of Roman numerals that run from I to XII twice. These give (roughly) the time at which the moon passes through the meridian of the place – its southing. Along the rim of the inner disc are the numbers from 1 to 30. An N (new moon) is at 1 and an F (full moon) at 15. The space between the ring of Roman numerals and the ring of Arabic numerals is partly textured and partly smooth, with the smoother regions corresponding to greater moonlight (thus at full moon, the entire region is smooth, while at new moon it is textured). The rim of the larger ring also once again has letters corresponding to the days of the week for twenty-eight days (one W is missing)
The object came to the Smithsonian from the collection of Henry Russell Wray.
This calendar medal closely resembles two described in detail by Ackerman. She suggests they are late eighteenth century English devices.
Silke Ackermann, “Maths and Memory: Calendar Medals in the British Museum Part II,” The Medal, Spring, 2005, vol. 46, esp. pp. 17-18. These are medals 110 and 111 in the catalog. They have British Museum catalog numbers 1901,1115.30 and 1901,1115.31.
Currently not on view
Object Name
calendar medal
date made
ca 1790
place made
United Kingdom: England
Physical Description
metal (overall material)
overall:.1 cm x 3.7 cm x 3.7 cm; 1/32 in x 1 15/32 in x 1 15/32 in
ID Number
accession number
catalog number
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History
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