They use alternating discs of silver, zinc, sulfur, and other materials to generate low currents of electricity.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 ?describing the bell in the European Journal o