'Wimshurst's Influence Machine, Recent Pattern', 1886.

Engraving from 'The Influence Machine, How to Make It and How to Use It' (1886) by James Wimshurst (1832-1903). Induction electrostatic machines like this were developed in the mid 19th century, replacing friction machines for demonstrating electrostatic sparks and other effects. The Wimshurst machine was affected les by atmospheric humidity than most other types. From about 1900 some Wimshurst machines were used to power X-ray tubes, but this was not very common. The principles of electrostatics are now used in photocopiers.