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The Beverly Clock is a clock situated in the 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 air-tight box to expand or contract, which pushes on a diaphragm. A six-degree Celsius temperature variation over the course of each day creates approximately enough pressure to raise a one-pound weight by one inch, which drives the clock mechanism.
A similar commercial example of this mechanism is known as the Atmos clock.
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 create the requisite amount of energy, the clock will not function. However, after environmental parameters readjust, the clock begins operating again.
See also 
- Long-term experiment
- Oxford Electric Bell (1840)
- Pitch drop experiment (1927)
- Cox's timepiece
- Atmos clock
- Clock of the Long Now
- L.E.S. Amon, A. Beverly, and J.N. Dodd (1984). "The Beverly clock" (abstract). European Journal of Physics 5 (4): 1957–197. Bibcode:1984EJPh....5..195A. doi:10.1088/0143-0807/5/4/002.
- Marc Abrahams (2001). "The Latest on Long-Running Experiments" (– Scholar search). Annals of Improbable Research 7 (3).[dead link]
- L.E.S. Amon and Hardwicke Knight. "Beverly, Arthur 1822 – 1907". Dictionary of New Zealand Biography. Ministry for Culture and Heritage. Retrieved 4 April 2011.