Fine English 18K gold demi-hunter retrograde perpetual calendar chronograph by
John Bennett, (later Sir John Bennett) Maker to the Royal Observatory, London, circa 1877.
Fine white enamel dial (clean hairlines) with indications for the chronograph, full
calendar and phases of the moon. Substantial plain polish demi-hunter case with
enamel numbers on the cover. The outside of the back cover looks as it should;
the inside of this cover shows signs of re-blocking. Frosted gilt 18 jewel movement with engraved balance cock
and the chronograph work visible on the back plate.
Unlike simple calendar watches, this mechanism ""knows"" the number of days in
each month and also accounts for leap year. This example is unusual, since for ease of
use only 12 months are shown on the dial. The day-of-the-month hand is retrograde,
which means that it completes an arc and then snaps back to 1.
With the addition of the chronograph mechanism this watch is quite rare.