Electrophorus, after Volta

Alessandro Volta (1745-1827), the inventor of the chemical battery, has also contributed considerably to static electricity. In 1782 he devised the ‘electrophorus’, or ‘that which carries away electricity’. The simple apparatus consists of a flat, circular insulating plate and a metal plate of roughly the same size: usually tin foil on wood. The insulator is rubbed with cat skin and is thus electrically charged. The metal plate is held just above the insulator and is touched with a finger. By influence (attraction at a distance) a charge of the same strength, but with an opposite sign, will flow from the earth, through the finger and onto the metal plate. This charge can be collected on a Leyden jar, after which the next charge can be accumulated in the same way. The influence electrostatic generator would be based on this principle later on. This specimen was made in 1929 to replace two older electrophori.