English Perpetual Calendar Medal by Thomas Cole, Easter 1735

English Perpetual Calendar Medal by Thomas Cole, Easter 1735

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Description
This is one of two English perpetual calendar medals in the collections using the Julian (rather than the present-day Gregorian) calendar. The Gregorian calendar would not be adopted in England until 1752. The small metal disc contains a wealth of calendrical information.
One side of the object has six concentric scales. The outermost scale give, for successive leap years, the day of the week of March 1 (the first day of the new year in the Julian calendar), as well as the date of Easter in successive years (with 1 indicating the month of March and 2 indicating April). Text next to this scale reads: EASTER (/) 1735.
The next innermost scale relates to times of the moon’s southing (e.g. the time the moon crosses the local meridian). It is labeled: SOUTH. The next innermost scale indicates the age of the moon on March 22 of successive years. This, the epact, increases by 11 days each year. The scale is labeled: EPACT. The three central scales on this side of the medal allow one to estimate the time of sunset for various days of the year. There is a central image of a sunset.
The reverse side of the medal has a 7 x 7 calendrical table. The first two rows serve as heads of columns, indicating months which begin on the same day of the Julian calendar. These are 9 and 1 (November and March), 6 (August), 11 and 3 (January and May), 8 (October), 5 and 2 (July and April), 10 and 7 (December and September), and 12 and 2 (February and June). Note that in later calendrical styles, January and February would be in the next year.
The day of the week represented by the numbers in a column depended on the year. For example, in the Julian calendar for 1735, the columns indicate dates of Saturdays. November and March had Saturdays with dates 1, 8, 15, 22, and 29; August had Saturdays with dates 2, 9, 16, 23, and 30; and so forth. Below the rows relating to months are five rows with squares numbered from 1 to 31. A mark in the last row reads: THO.COLE.
The object came to the Smithsonian from the collection of Henry Russell Wray.
Compare MA.316919.1.
There is a very similar calendar medal, also for 1735 and by Cole, in the collections of the British Museum. It is described by Ackermann.
Reference:
Silke Ackermann, “Maths and Memory: Calendar Medals in the British Museum Part I,” The Medal, Autumn, 2004, vol. 45, esp. pp. 18-20. The example in the British Museum has catalog number 1901,1018.2 and is described in their online catalog.
Location
Currently not on view
Object Name
calendar medal
date made
ca 1735
maker
Thomas Cole
place made
United Kingdom
Physical Description
brass (overall material)
Measurements
overall:.1 cm x 4.8 cm x 4.8 cm; 1/32 in x 1 7/8 in x 1 7/8 in
ID Number
MA.316919.2
catalog number
316919.2
accession number
228694
subject
Mathematics
Calendar
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History
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