Wireles receiver (coherer) , 1897.
© 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 in June 1894 at the Royal Institution in London. This coherer is one of many variations developed during the 1890s. The coherer is the small ebonite cup on the top of the instrument.