. The Becquerel rays and the properties of radium . of the a-rays, it is only possible toproduce a very slight curvatuie of the rays. Thusthe vessel at the bottom of which the radium isplaced must be made very narrow. It must con-sist of a mere slit between two parallel metalplates; for if the plates were not very close,the rays could get out in spite of their slightcurvature. 76 THE BECQUEREL RAYS Jn/low tf It is evident that one such slit cannot give outvery much radiation, on account of its get enough rays to work with conveniently, itis necessary to have a number of parallel
. The Becquerel rays and the properties of radium . of the a-rays, it is only possible toproduce a very slight curvatuie of the rays. Thusthe vessel at the bottom of which the radium isplaced must be made very narrow. It must con-sist of a mere slit between two parallel metalplates; for if the plates were not very close,the rays could get out in spite of their slightcurvature. 76 THE BECQUEREL RAYS Jn/low tf It is evident that one such slit cannot give outvery much radiation, on account of its get enough rays to work with conveniently, itis necessary to have a number of parallel slits, so thatthe radium is placed in a layer at the bottom of abox containing a number of paiallel plates, withnarrow spaces between. The rays come through these narrow in-terspaces and troscope (fig. 17).It is necessarythat the narrowslits should bereasonably longin order that themagnetic forcemay act on therays along a con-siderable , however, ab-sorbs the a-raysvery freely, andif air filled thespaces, practi-cally no rayswould getWo. Outflow ofByOrogen lrci. 17.—UiiUioiliM-ir« nrraiigninnnt for olisorviiiK oC o-riiyH. Tim \\\\m ll|i lic^lwi^iii llio iniiUil ^ 1, iTiiiivliKlit«, unci eril(!i the iil(!iitr(in(;ii|i(i, ciiiwliit! cIlMcliiiigii wi.,.., til I Ul 1^11. Wliuii liiiitiitllo lli;lil is upiilicil iicrpoiulleuliii In the imiiur, the j. 1 i ■ !t through the aiits., cannot exhaust rays ure curved, and can no longov geThus discharge is stopped the entire appa-ratus, for the presence of some gas in the electro-scope is necessary to enable the rays to discharge ;and we cannot exhaust the slits without exhaustingthe electroscope, for it would be impracticable tomake an air-tight partition thin enough to let thea-rays get through. The difficulty was got over by THE a-EAYS 77 ^ ^^ filling the apparatus with hydrogen, which is muchless opaque to the rays than air. The vessel with the series of slits was placedbetween the poles of a
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectradioac, bookyear1904
