ライデン瓶
The central bell's chain is put in contact with the inner surface of a Leyden jar, while the outside surface of the jar is put in contact with the metal stand. Thus, the central bell takes its charge from the inner surface of the jar, while the outer surface charges the two bells on the conductive chains. This causes the bells to have a difference in electrical potential equal to that between the inner and outer surfaces of the jar. The hanging metal clappers will be attracted to one bell, will touch it, pick up its charge, and be repelled; they will then swing across to the other bell, and do the same there. Each time the clappers touch a bell, charge is transferred between the inner and outer surfaces of the Leyden jar. When the jar is completely discharged, the bells will stop ringing.