These documents, which cover the years 1877-1885, consist mainly of letters to and from William H. Preece, a prominent electrical engineer and divisional superintendent of the British Post Office. The documents relate primarily to phonographs, telephones, and electric lighting. Included are items pertaining to Preece's demonstration of the phonograph at the Royal Institution in February 1878 and his lecture at the Physical Society of London the following March. Some of the letters concern Edison's controversy with Preece and British inventor David E. Hughes over who was the first to discover that carbon and other semiconductors vary their resistance under pressure. Other correspondents include inventor Alexander Graham Bell, British physicist and electrical engineer Sir William Thomson (later Lord Kelvin), and Edison business associates Henry Bentley, George E. Gourard, William Orton, and Frank L. Pope.
A description of the archival collection can be obtained by choosing the Collections search option in the IET Archives online catalog and entering UK0108 SC MSS 022 in the reference number box. Courtesy of the Institution of Electrical Engineers Archives.