Signalling through space without wires : being a description of the work of Hertz & his successors . lass changes, and the metal beginsto cling to the glass. They suppose that Warburgs vacuumtubes of pure sodium may behave similarly, and show photo-electric sensibility. The Same, p. 166.—On a Checking Action of Magnetism on Photo-Electric Discharge in Rarefied Gases. The authors point out analogies between the above effects and those they had observed in the action of glowing bodies in air, and they mention Lenard and Wolfs experiments * See Fig. 7, page 9 PHOTO-ELECTRIC PHENOMENA. 119 Wied. A
Signalling through space without wires : being a description of the work of Hertz & his successors . lass changes, and the metal beginsto cling to the glass. They suppose that Warburgs vacuumtubes of pure sodium may behave similarly, and show photo-electric sensibility. The Same, p. 166.—On a Checking Action of Magnetism on Photo-Electric Discharge in Rarefied Gases. The authors point out analogies between the above effects and those they had observed in the action of glowing bodies in air, and they mention Lenard and Wolfs experiments * See Fig. 7, page 9 PHOTO-ELECTRIC PHENOMENA. 119 Wied. Ann. XXXVII., p. 443), tending to show that theeffect is due to a disintegrating or evaporative effect of lighton surfaces. Elster and Geitel had observed that thedischarging power of glowing bodies was diminished byapplication of a magnetic field, the effect being the same as ifthe temperature was lowered ; and they proceed to try if thedischarge of negative electricity from illuminated surfaces inhighly-rarefied gas could also be checked or hindered by a magnetic field. They find that it ,To of Fig. 60.—The sodium and mercury are introducedthrough the tube S into the globe K. The tube S is then closed, a pumpapplied to X, and exhaustion carried on for some days. T is an openfunnel sealed into the tube (as is done in some vacuum tubes made byHoltz) to show a curious unilateral conductivity of rarefied gas. The objectof this funnel is to permit metal from the interior, free from scum, to beintroduced from K to D when the whole is tilted. Thus a bright surfaceis exposed to the earth ring R. It can be charged negatively, and its leakunder illumination be measured, through the terminal D. Sometimes thetube is inverted, so that the active surface may be at D, further from theearth wire. Using the light from sparks admitted through a quartrwindow into the vacuum tube when a negatively-chargedamalgamated zinc surface was exposed near an earth-
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Keywords: ., bookcentury1900, bookdecade1900, bookidsi, booksubjectelectricity
