Bell's centennial telephone transmitter, 1876.
© Science Museum / Science & Society Picture Library
Replica. Alexander Graham Bell's (1847-1922) telephone was the star attraction at the American Centennial Exhibition in Philadelphia in June 1876. Sir William Thomson, later Lord Kelvin (1824-1907), one of the exhibition judges, described the new invention as 'the greatest by far of all the marvels of the electric telegraph'. Telephones did not appear in England until the following year, when W H Preece, electrician to the Post Office, brought two telephones back from a visit to America and demonstrated them to the British Asociation. By the summer of 1878, telephones were available for use on private wires at a cost of £10.