210 On the Intensely Penetrating Rays of Radium. [Aug. 5, 



to have much to recommend it. The /3 rays should, by analogy with 

 the cathode rays in a vacuum tube, produce Kontgen rays when they 

 strike a solid obstacle, and these Kontgen rays should be much more 

 penetrating than the /3 rays themselves. The y rays seem at first sight 

 to be just what should be expected. But the present paper shows 

 that in one respect, at all events, the y rays behave quite differently to 

 Kontgen rays, while, on the other hand, they resemble the a and /3 rays. 

 There seems to be a possibility that they too are of a corpuscular 

 mature, though uncharged with electricity. This would account for 

 the absence of magnetic deflection 



I do not think that the absence ot conspicuous Kontgen radiation is 

 very hard to understand, if we consider that the current emitted in 

 cathode rays by a square inch of intensely active radium is only 

 10~ n amperes; the current through a focus tube is of the order 

 10~ 2 amperes, and probably a great part of this is carried by the 

 cathode rays. 



