THE BECQUEREL RAYS FROM RADIUM. 



101 



In their study so far, we have discovered no property not 

 shared by the positive ions, corpuscles or X-rays emitted by 

 candle flames, hot wires or Crooks' tubes as elucidated in 

 Part III. Can it be that Becquerel rays are identical with 

 these bodies? And if so, which? Fortunately they have 

 one more strange property which Becquerel discovered them 

 to possess, and which, as it turns out, affords a master key to 

 their nature. 



BECQUEREL RAYS ARE BENT BY A MAGNET. 



Becquerel proved 

 this by one of his 

 characteristic fec- 

 und, -simple exper- 

 iments. Taking a 

 narrow photo- 

 graphic plate en- 

 veloped in black 

 paper, he placed it 

 horizontally be- 

 tween the poles of 

 a powerful electro- 

 magnet (Fig. 30). 

 On the black en- 

 velope of the plate 

 he then placed a 

 little lead trough 

 containing a small 

 amount of the ra- 

 dium compound. Rg 3Q M . Becquerel and the experiment 

 The rays could thus with the magnet. 



affect the plate only by bending over,, for the lead is opaque. 

 He energized the magnet; then after a certain time, he re- 



