The Oxford Electric Bell is a battery-powered bell that was initially set on display at the Clarendon Laboratory at Oxford University in 1840. The device is powered by the Clarendon Dry Pile, a battery that has been running for 175 years and is composed of alternating layers of sulfur, silver, and zinc.

Even though most people cannot hear it ringing, the clapper can be observed moving back and forth between the two sections of the device. It has been estimated that the bell has rung about 10 billion times since the day it started operating.

[David Glover-Aoki | Via]