Ring transformer, 1892

John Gavey's ring transformer, used between Lavernock and Flat Holm, made by John Gavey, Wales, 1892. Mounted on polished wooden board

William Henry Preece (1834-1913) became Engineer-in-Chief of the Post Office in 1892. At the time he was unconvinced of the theories of Heinrich Hertz as a basis for wireless communication but considered that electromagnetic induction could be used for wireless telegraphy over short distances. John Gavey, his assistant, made this ring transformer for trials held in Wales, between Lavernock Point and the island of Flat Holm, just outside Cardiff, in 1892. The system worked but was impractical for widescale application.