. The Becquerel rays and the properties of radium. l,and are discharged. Then they begin to charge up result, the failure of insulation is not serious enough to affect the use ofparaffin in this experiment. THE ;8-EAYS 68 again, and so on indefinitely. The time that theleaves take to diverge and collapse again once depends,of course, on how muchradium is used. But withseveral milligrammes of apure radium salt it is easyto make an apparatuswhich will go through itscycle in the course of aminute. This apparatusis probably the nearest ap-proach to perpetual motionthat has ever been attain-ed. The
. The Becquerel rays and the properties of radium. l,and are discharged. Then they begin to charge up result, the failure of insulation is not serious enough to affect the use ofparaffin in this experiment. THE ;8-EAYS 68 again, and so on indefinitely. The time that theleaves take to diverge and collapse again once depends,of course, on how muchradium is used. But withseveral milligrammes of apure radium salt it is easyto make an apparatuswhich will go through itscycle in the course of aminute. This apparatusis probably the nearest ap-proach to perpetual motionthat has ever been attain-ed. The divergence andcollapse of the leaves ismaintained without ceasing,and can only stop when theradium loses its long this may take,we do not very exactlyknow; but hundreds ofyears at least must elapsebefore the forces whichcause the leaves to movehave ceased to act. Enough electricity hasbeen accumulated by the self-electrification of radiumto even give an electricshock. It happened Horn had sealed upsome radium salt hermeti-. EarOo Fig. 16.—Ai-vangement for exhibiting theself-electrifioation of radium. A glass cylinder,a, is provided with a stopper, b. From thisthe tliin glass tube, d, containing radium, ishung by the glass rod, e, which serves as aninsulating support, d is covered with a film ofphosphoric acid, which makes it a the other end is a brass cap,/, which carriesthe gold leaves, g. The whoJe is exhaustedthrough h, which subsequently serves as ameans of supporting it. d loses negativeelectricity, thus acquiring a positive charge,and tiie leaves, y, diverge. The divergenceincreases until the leaves touch the tinfoilstrips, A h, which are connected to the earththrough a wire, i-, sealed into the glass. Thistouching discharges the leaves, but they beginto diverge again immediately, if the radiumpreparation is active. This oscillation of theleaves goes oa indefinitely. cally in a tube of glasswhich possessed good insulating power; the
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectradiati, bookyear1906
