[31] Called “canal rays” by the German physicist, Eugen Goldstein, who, in 1886, first obtained them by the use of a perforated cathode; that is, he used a metallic tube for a cathode, through which tube, called by Goldstein a “canal,” the rays issued. CHAPTER 7 THE DISCOVERY OF WIRELESS TELEGRAPHY The experimental foundation for the discovery of wireless telegraphy was laid by the researches of Faraday.[32] Accepting Faraday’s physical views as a point of departure, James Clerk Maxwell (1831-1879), Professor of Experimental Physics in the University of Cambridge, began (about 1860) the development of his constructive speculations in electrical theory which culminated in the now universally accepted electromagnetic theory of light.[33] Fourteen years after the publication of Maxwell’s classic treatise, Heinrich Hertz (1859-1894)—a brilliant pupil of Helmholtz (1821-1894)—succeeded in producing electrical discharges from a Leyden jar, which oscillations in turn gave rise to electromagnetic waves of far greater length than any previously known.[34] Hertz demonstrated also that the velocity of propagation of these waves was the same as that of light-waves—approximately 186,000 miles a second, equivalent to about seven times the circumference of the earth in one second. It was shown that the only difference between the Hertzian (“wireless”) waves, for example, and the light-waves, is in their respective length, or, reciprocally, their rates of vibration per second. Hertz later demonstrated that these invisible waves produced by a Leyden jar could be reflected, refracted, and polarized, as in the case with the far shorter light-waves or rays.[35] These results had been predicted by Maxwell. In this great discovery the foundation for wireless telegraphy and wireless telephony was laid—for Hertz had found what are now known as “wireless” or radio waves—destined, perhaps, to revolutionize our methods of obtaining power for machinery, and for transportation, as they have already revolutionized our methods of communication. Hertz had done more than this: for his investigations made possible a far more satisfactory research into the structure of atoms. “If we were asked to pick out one date that stands out more prominently than others in our acquisition of knowledge bearing upon the structure of matter,” says Dr. Albert C. Crehore, “it might be this epoch-making work of Hertz.”[36] While it is true that the waves that Hertz discovered and measured “differ from light-waves merely in wave-length or period of vibration and quality,” on the other hand the difference in wave-length is so great that no instrument had as yet been devised to measure or detect waves that were meters long, as compared with light-waves but a minute fraction of a centimeter in length.