Battery-Powered Bell Still Ringing 175 Years After Its Creation

A battery-powered bell at the University of Oxford has been ringing for 175 years, and scientists essentially have no idea why. Its ring is so quiet that the human ear can't hear it, but it's there, and researchers are baffled as to why the battery hasn't died yet.

The Oxford Electric Bell was hand-crafted in the 19th century by London instrument makers Watkin and Hill. It is unknown exactly when it was manufactured, although it has an accompanying handwritten note that says, "set up in 1840" next to it. Oxford researchers estimate that it has now rung approximately ten million times. Its power source currently holds the Guinness World Record for "world's most durable battery."

We know that the battery is made of "dry piles," one of the earliest forms of electric battery. "What the piles are made of is not known with certainty, but it is clear that the outer coating is of sulphur, and this seals in the cells and the electrolyte," AJ Croft, a former researcher at the Clarendon Laboratory, wrote in a 1984 paper about the mystery of the bell. "Piles similar to this were made by Zamboni, whose batteries were constituted of about 2,000 pairs of discs of tin foil glued to paper impregnated with zinc sulphate and coated on the other side with manganese dioxide."

Unfortunately, this research won't likely lead to a cell phone battery that can last for 175 years. Every time the bell's battery oscillates between the sides of the bell, it only draws 1 nanoAmp, which is an extraordinarily low current that wouldn't be applicable to any modern technologies.

Since we don't know why the battery still works, we have no idea how long it will last. We can dream that the bell will last forever, because that would be fascinating, but it will likely stop ringing eventually. According to Croft, "the clapper seems more likely to wear out than the electro-chemical energy." On the plus side, if the bell stops ringing, it will be far easier to solve this decades-old mystery.