(Image: Leo Panthera)
This is the Clarendon Dry Pile, a device so old that documentation about its origins is a bit spotty. It was set up at the Clarendon Laboratory at Oxford University in 1840. It’s a dry pile, which means that it’s made of alternating layers of sulfur, silver, and zinc that generate electrical current.
Mechanically, it’s a bell, which is why it’s sometimes called the Oxford Electric Bell. The clapper between the two sections oscillates back and forth. The movements are too small to see easily and the sounds are too quiet to hear unaided. It has rung approximately 10 billion times while in operation. You can read more about this remarkable antique at Vice.
-via Marginal Revolution