Electric bell still rings after 180 years

An electric bell installed in Oxford in 1840 continues to function today, having rung approximately ten billion times, according to reports from the University of Oxford's historical archive.

Original batteries remain unopened

The bell is powered by two dry cells that have never been opened, and their exact composition remains unknown. The university describes the bell as the oldest functioning laboratory apparatus and notes it holds the Guinness World Record for the most durable battery in the world.

Simple setup powers the bell

The original batteries power a simple setup. Mounted in series and coated with a layer of sulfur, each battery sits above a small brass bell. A 4 mm metal ball hangs between the two bells, touching one, charging, and then moving to the other, repeating the motion about twice per second.

Efficiency ensures longevity

The device's longevity is due to the efficiency of the process. The electrostatic force requires a high voltage but very little current. The laboratory archive dismisses the idea that the bell is a perpetual motion machine, emphasizing that the batteries will eventually balance their charges unless the ball wears out first.

Composition of batteries remains a mystery

Despite extensive research, the exact composition of the two batteries remains unknown, adding to the mystery of how they have remained functional for over 180 years.