Marconi coherer and tapper, 1900.
© Science Museum / Science & Society Picture Library
Invented in 1890 by the Frenchman Edouard Branly (1844-1940), the coherer is one of the most important of early radio wave detectors. Its potential for wireles communication was realised by the English physicist Sir Oliver Lodge who gave the first public demonstration of wireles transmision and reception at the Royal Institution, London in June, 1894. Guglielmo Marconi (1874-1937) whose coherer (the glas tube) and tapper is shown here was to realise the true potential of radio after the patenting of his tuned transmitter in 1900.