Signalling through space without wires : being a description of the work of Hertz & his successors (1900)
Lodge, Oliver, Sir, 1851-1940, Hertz, Heinrich, 1857-1894 · London : "The Electrician" Printing and Publishing Company, Limited · leaf 109
dden increase in the conduc-tivity. Thus, a layer of copper reduced by hydrogen, whichdoes not become conducting under the influence of the electricspark or otherwise, will become so on being submitted to apressure of 500 grammes to the square centimetre (7ib. persquare inch). Instead of using… … Fig. 55. A layer of this kind, polished with a burnisher, has a verjvariable resistance. With a little care one can prepare sheetswhich are more or less sensitive to electrical action. Metal powder or metal filings are not the only sensitivesubstances, as powdered galena, which is slightly…
Electric waves · Telegraph, Wireless · Electricity · Wireless Technology
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