File:EB1911 Telegraph - Morse's Conduction Method.jpg

English: A circuit for wireless telegraphy: Morse showed, by experiments made in 1842 on a canal at Washington, that it was possible to interrupt the metallic electric circuit in two places and yet retain power of electric communication. On each side of the canal, at a considerable distance apart, metal plates e e (see figure) were sunk in the water; the pair on one side were connected by a battery B, and the pair on the other by a galvanometer or telegraphic receiver R. Under these circumstances a small portion of the current from the battery is shunted through the galvanometer circuit, and can be used to make electric signals. Morse and Gale, who assisted him, found, however, that the distance of the plates up and down the canal must be at least three or four times the width of the canal to obtain successful results. Numerous investigators followed in Morse's footsteps. James Bowman Lindsay of Dundee, between 1845 and 1854, reinvented and even patented Morse's method, and practically put the plan into operation for experimental purposes across the river Tay. J. W. Wilkins in 1849, and H. Highton in experiments described in 1872, also revived the same suggestion for wireless telegraphy.