Henley's universal discharger

This discharger was specially developed to send electric charges through various materials. This type of discharger is often called Henley’s discharger, after the deviser William Henley. In 1770, this London textile manufacturer also devised an electrometer, an instrument for measuring the power and the nature of an electric discharge. The height of the circular object table in the middle can be adjusted by turning the set screw. An electrostatic generator is connected to the ends of the rotatable rods. The first director of Teylers Museum, Martinus van Marum, used this discharger in his experiments with the electrostatic generator. He investigated the effects of electric spark discharges. In his experiments, various materials, such as glass, wood, metal, were tested, which resulted in phenomena like breaking and melting. Apart from this specimen, Van Marum bought, in 1785, a second discharger after the design of William Henley at the instrument maker John Cuthbertson who worked in Amsterdam [see 1154].