Beverly Clock - Wikipedia, the free encyclopedia
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 has been running continuously without the need to be wound up since its construction in 1864 by Arthur Beverly. It is a contender for the title of longest continuously running scientific experiment.
The clock mechanism is driven by variations in atmospheric pressure and by daily temperature variations; of the two, the temperature variations are the more important. Either cause the air in a one cubic-foot air-tight box to expand and contract, pushing on a diaphragm. A six-degree Celsius temperature variation over the course of each day creates enough pressure to raise a one-pound weight by one inch (energy extracted = 11 Joule), which drives the clock mechanism.
A commercial version of this design is known as the Atmos clock.
Whilst the clock has not needed winding since it was made by Arthur Beverly in 1864, it has stopped on a number of occasions, when its mechanism needed cleaning, when there was a mechanical failure, when the Physics Department moved to new quarters, and on occasions when the ambient temperature has not fluctuated sufficiently. After environmental parameters readjust, the clock begins operating again.