The Beverly Clock is a clock situated in the 3rd floor lift foyer of the Department of Physics at the University of Otago, Dunedin, New Zealand. The clock is still running despite never having been manually wound since its construction in 1864 by Arthur Beverly.
The clock's mechanism is driven by variations in atmospheric pressure, and by daily temperature variations; of the two, temperature variations are more important. Either causes the air in a one cubic-foot (28 litre) air-tight box to expand or contract, which pushes on a diaphragm. A temperature variation of six degrees Fahrenheit (3.3 K) over the course of each day creates approximately enough pressure to raise a one-pound weight by one inch (equivalent to 0.113 Joules or 31 μWh), which drives the clock mechanism.
While the clock has not been wound since it was made by Arthur Beverly in 1864, it has stopped on a number of occasions, such as when its mechanism needed cleaning or there was a mechanical failure, and when the Physics Department moved to new quarters. As well, on occasions when the ambient temperature has not fluctuated sufficiently to absorb the requisite amount of energy, the clock will not function. However, after environmental parameters readjust, the clock begins operating again.
- Amon, L.E.S.; Beverly, A.; Dodd, J.N. (1984). "The Beverly clock". European Journal of Physics. 5 (4): 195–7. Bibcode:1984EJPh....5..195A. doi:10.1088/0143-0807/5/4/002.CS1 maint: ref=harv (link)
- Abrahams, Marc (2001). "The Latest on Long-Running Experiments". Annals of Improbable Research. 7 (3). Archived from the original on 2018-02-21. Retrieved 2018-02-20.CS1 maint: ref=harv (link)
- Amon L.E.S.; Knight, Hardwicke; Beverly, Arthur. "1B20". Dictionary of New Zealand Biography. Ministry for Culture and Heritage.CS1 maint: uses authors parameter (link)