Caption:
Stephen Gray (1666-1736) English scientist born at Canterbury, Kent, credited with the discovery of the flow of electricity. Artist's impression of Gray passing electricity from a glass globe electrostatic machine down a 44.8 metere (147 feet) length of packthread (1729). Engraving from "A Popular History of Science" by Robert Routledge (London, 1881). (Photo by: Universal History Archive/UIG via Getty Images)