The following reply was received from the Assistant Curator, United Grand Lodge of England, Great Queen Street, London.
Thank you for your enquiry. This is quite a fascinating object, never seen the like before, however what we believe it to be is a watch fob that is also perpetual calendar. The numbers are on a disc that turns via that square nut on the back, most likely via the same key that would wind a pocket watch. The owner turns the disc so that the numbers match up with the days of the week and he has a reminder of the date. It’s clearly designed to be looked at by whoever was wearing it. I don’t think there is a winding mechanism of any sort, just the internal circular plate on a pivot. You can find perpetual calendar fobs nowadays, but they are usually a bit more complicated and not masonic.
Difficult to put a date on it, late 18th century is our best guess and it might be continental, not British. Something in the design of the compasses suggests that to us. A lovely and quite unique object, thank you for contacting us about it.
Yours sincerely
Assistant Curator.
Footnote
Although the Assistant Curator suggested it may be continetal, I note the days of the week are signified by English spelling capitals.
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