xviii, 278, [1] pp. (8vo) original blue cloth, spine lettered in gilt. Second Edition in English.

"Experimental proof by Hertz of the Faraday-Maxwell hypothesis that electrical waves and be projected through space was begun in 1887, eight years after Maxwell’s death. The two main requirements were (a) a method of producing the waves, supposing that they existed, and (b) a method of detecting them once they were produced. Hertz found the first problem easy to solve. He used the oscillatory discharge of a condenser. Detection was much more difficult, because there then existed no means of detecting currents alternating at the high speed of these waves. Hertz in fact used an effect as old as the discovery of electricity itself-the electric spark. By inducing the waves to produce an electric spark at a distance, with no apparent connexion between the oscillator and the spark gap, and by moving the sparking apparatus so that the length of the spark varied, he proved beyond question the passage of electric waves through space."- (PMM).  Hook & Norman, Origins of Cyberspace, 158; Printing and the mind of man, 377 (for the German 1st edition).