Signalling through space without wires : being a description of the work of Hertz & his successors . yards apart (Fig. 4).I charge and discharge one jar, and observe that the surgingsset up in the other can cause it to overflow if it is syntonisedwith the first.* * See Nature, Vol. XLL, p. 368, where I first described this experiment;or quotation in J. J. Thomsons Recent Researches, p. 395. WORK OF HERTZ LECTURE. 7 A closed circuit such as this is a feeble radiator and a feebleabsorber, so it is not adapted for action at a distance. In fact,I doubt whether it will visibly act at a range beyond
Signalling through space without wires : being a description of the work of Hertz & his successors . yards apart (Fig. 4).I charge and discharge one jar, and observe that the surgingsset up in the other can cause it to overflow if it is syntonisedwith the first.* * See Nature, Vol. XLL, p. 368, where I first described this experiment;or quotation in J. J. Thomsons Recent Researches, p. 395. WORK OF HERTZ LECTURE. 7 A closed circuit such as this is a feeble radiator and a feebleabsorber, so it is not adapted for action at a distance. In fact,I doubt whether it will visibly act at a range beyond the JA atwhich true radiation of broken-off energy occurs. If the coat-ings of the jar are separated to a greater distance, so that thedielectric is more exposed, it radiates better; because in trueradiation the electrostatic and the magnetic energies mustbe equal, whereas in a ring circuit the magnetic energy pre-dominates. By separating the coats of the jar as far as possiblewe get a typical Hertz vibrator (Fig. 5), whose dielectricextends out into the room, and thus radiates very Fig. 5.—Standard Hertz Radiator. Ordinary Size Hertz Vibrator. In consequence of its radiation of energy, its vibrations arerapidly damped, and it only gives some three or four good strongswings (Fig. 1). Hence it follows that it has a wide range ofexcitation; , it can excite sparks in conductors barely at allin tune with it. The two conditions, conspicuous energy of radiation andpersistent vibration electrically produced, are at present incom-patible. Whenever these two conditions coexist, considerablepower or activity will, of course, be necessary in the source ofenergy. At present they only coexist in the sun and otherstars, in the electric arc, and in furnaces. Two Circular Vibrators Sparking in receiver Hertz used was chiefly a circular resonator(Fig. 6), not a good absorber but a persistent vibrator, welladapted for picking up disturbances of precise and measur
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