Muschenbroek's air pump, 1876.
© Science Museum / Science & Society Picture Library
Photograph of a scientific instrument exhibited in the Special Loan Collections of Scientific Apparatus at the South Kensington Museum, London, in 1876. In 1745 the Dutch physicist and mathematician Pieter van Muschenbroek (1692-1761) invented a cheap and convenient device for storing an electric charge. The Leyden jar, named after the Dutch town where it was devised, was the first device that could store large amounts of charge and consisted of a glas phial which was partially filled with water and contained a thick conducting wire. The jar was charged by bringing an exposed end of this conducting wire into contact with a friction device that generated static electricity.