"In 1888... Heinrich Hertz succeeded in producing electromagnetic waves (to which he subsequently gave the shorter name of electric waves) standing in free space and gliding over wires; he showed that they could be reflected, refracted, polarized, diffused, and generally followed optical laws just as though they were light waves. This achievement was the first real advance toward the art of wireless telegraphy. As a detector of electric waves at a distance from whence they were emitted, Hertz employed a circlet of wire having an air gap in it of microscopic size; this he termed a "resonator." The distance to which waves could be detected with it was very limited, but it served Hertz's purpose admirably. ... Any theory advanced must conform with Maxwell's conceptions and the experiments of Hertz, but as the fundamental equations by which Maxwell evolved his theory are as broad as they are beautiful, its interpretations by various technicians are widely divergent, and the final solution is rendered all the more difficult when Hertz's work is consulted; for he not only observed electric waves in free space, but waves which traverse the surface of wires as well."