1764 This watch demonstrates Thomas Mudge's exceptional skill. It contains one of the first automatic perpetual calendar mechanisms. The extra day in Leap Years is shown automatically. If the watch is kept going, the date will be correct for 100 years. Thomas Mudge, London Fusee, ruby cylinder escapement, balance with spring (P&E 1977.0702.1)
aperture=f4.5 focal length: 60.0 mm exposure 1/200 sec ISO: 3200