Text: A device consisting of two thin sheets of brass, designated in the illustration as A, A. These are 4 inches by 11.8 inches and are placed about 1 inch apart. Soldered to one plate is a fine platinum wire and to the other plate is a fine platinum-nickel wire. These two wires are connected together at J to form a thermal junction and are then led off at right angles and are soldered at their other ends to the leads R. R. of a sensitive galvanometer (q.v.). This resonance system is fixed at the focal line of a suitable cylindrical metallic reflector. When electric waves with the electric force parallel to A A fall on this receiver, electric oscillations between A and A produce heating at the junction J which is the point of contact between the two dissimilar metals. In consequence, the heat developed gives rise to a thermoelectromotive force at the junction and consequently to a current in the galvanometer. This instrument can be used to detect and measure electric waves.

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Source: 190