. The Becquerel rays and the properties of radium . , where it is condensed. The liquid airis contained in a double walled vessel, c, with a vacuumbetween the walls. This serves to prevent the access ofheat. While h is surrounded by liquid air, no emanationcan escape through d, and it has lost all dischargingpower. When the liquid air is removed, the accumulateduiitanatlon evaporates, and the issuing air is stronglyradio-active. CHANGES IN EADIO-ACTIVE BODIES 115 in the solid form, and is deposited on the walls of theU tube. The whole process may be watched in thedark. The air charged with ema
. The Becquerel rays and the properties of radium . , where it is condensed. The liquid airis contained in a double walled vessel, c, with a vacuumbetween the walls. This serves to prevent the access ofheat. While h is surrounded by liquid air, no emanationcan escape through d, and it has lost all dischargingpower. When the liquid air is removed, the accumulateduiitanatlon evaporates, and the issuing air is stronglyradio-active. CHANGES IN EADIO-ACTIVE BODIES 115 in the solid form, and is deposited on the walls of theU tube. The whole process may be watched in thedark. The air charged with emanation causes visiblefluorescence in the glass tubes. But the fluorescencedoes not extend beyond the cooled portion of theU tube when it condenses. The accumulated emana-tion condensed in the tube shows a brilliant fluor-escence, proving, incidentally, that even at this lowtemperature it is still able to emit Becquerel rays. The condensationof the emanation canbe shown even moreeffectively by an-other emanation, withlittle admixture. as of any other gas aspossible, is intro-duced into a glassglobe (Fig. 23) con-taining zinc sul-phide, which fluor- ■^ 1 . n ■ 1 ■ 23.—Arrangement for sliowhig coiulciisation eSCeS brilliantlv of tli •■•in*- An inverted U-sliapod tube carries J at each end a glass bulb. Tlie larger bulb, a, contains nnrlov i + a inflnonno ^™^ sulphide or other fluorescent materials. The Uliuei lUb lllllUtJllUtJ. arrangement is exhausted of air, and the emanation +in<vi»Tifli trodnced through the stopcocic, c, which is then ^-/OminUIllCaXilUg Wlun closed. The zinc eulpliide glows brilliantly. On ,1 111 1 1 immersing h in liquid air, the emanation all condenses, the globe by a snort and a loses its luminosity. When S is allowed to heat . , 1 ^^ up again, the luminosity is restored. tube IS another small bulb which can be immersed in liquid air. As soonas this is done, all the emanation condenses in thebulb, so tha
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectradioac, bookyear1904
