Calendar of Discovery and Invention

Abstract

February 20, 1880.—In one of the notebooks of David Edward Hughes preserved at the British Museum is an entry dated Feb. 20, 1880: “Mr. Spottiswoode, President of the Royal Society, Prof. Stokes, and Prof. Huxley visited me to-day at halfpast 3 P.M. and remained until 6 P.M. in order to witness my experiments with the extra current Thermopile, etc.” Hughes was then making experiments in the transmission of signals across space by means of the radiation given off by what he called the ‘extra current’ from a small spark coil, using for reception a Bell telephone and battery connected to a separate receiving circuit including sometimes a microphone. Neither Hughes, however, nor his visitors had any conception that the effects obtained were due to electromagnetic waves.