Faraday's generating coil. This was made by Michael Faraday in 1831, and consists of a coil of copper wire wound around a hollow core. Moving a magnetised iron rod through the coil induces a current in the coil. Faraday showed that the magnet had to be in motion to induce a current, an early demonstration of converting a mechanical energy into electrical energy. This was the foundation of modern dynamos. This item is now on display at the Royal Institution, London.