440 



Mr. A. J. Dempster on the Ionization 



Since in the high vacuum the free path of the molecules 

 is very great, the positives which are still formed by the 

 dense stream of corpuscles coming from the Wehnelt cathode 

 make very few collisions with the hydrogen molecules. 



Magnet 



ic 



Field 



Hence these positive molecules are analysed in the condition 

 in which they are just after they have been ionized. We 

 must conclude, then, that electrons ionize only by detaching 



