Beverly Clock

The clock is still running despite never having been manually wound since its construction in 1864 by Arthur Beverly.

[2] The clock's mechanism is driven by variations in daily temperature and, to a lesser extent, in atmospheric pressure.

Either causes the air in a one-cubic-foot (28-litre) airtight box to expand or contract, which pushes on a diaphragm.

A temperature variation of 6 °F (3.3 °C) over the course of each day creates approximately enough pressure to raise a one-pound weight by one inch (equivalent to 13 mJ or 3.6 μWh), which drives the clock mechanism.

Also, on occasions when the ambient temperature does not fluctuate sufficiently to supply the requisite amount of energy, the clock will not function.

The Beverly Clock as it now stands in the Physics Department at the University of Otago
The inner mechanism of the Beverly clock showing chain, sprockets and torsional pendulum