134 Generating Economic Cycles 



par des rayons positifs tres deviables par le ma- 

 gnetisme." ^ 



Vegard then, according to Stormer, not only abandons 

 his own view but leans toward the Birkeland theory 

 which attributes the phenomena to the negatively 

 charged rays. 



As for himself, Stormer says: 



"De la discussion . . . dans le Terrestrial Magne- 

 tism, je tirai ... la conclusion suivante: * il semble 

 comma demontre que I'aurore etait due a des cor- 

 puscles charges d'electricite positive.' MM. Kr. 

 Birkeland et Vegard ont critique cette conclusion, 

 et le plus prudent sera probablement de ne pas pren- 

 dre une resolution definitive avant d 'avoir a dis- 

 position une serie de pareilles observations. En 

 effet, on ne sait pas encore le role exact joue dans un 

 pareil phenomene par des courants terrestres ou par 

 des courants corpusculaires en dehors de I'atmo- 

 sphere." ^ 



But we have seen that whether the rays be negative 

 or positive, a-rays or jS-rays, they are deflectible by 

 either an electrostatic or a magnetic field. Further- 

 more, as we have learned, C. T. R. Wilson has proved 

 experimentally that the gaseous ions produced by ioniz- 

 ing radiation may become nuclei for the condensation of 

 water vapor and has suggested that important phe- 

 nomena of thunderstorms may be related to variations 



^ Carl Stormer, Rapport sur une expedition d'aurores boreales a Bossekop 

 et Store Korsnes pendant le printemps de I'annee 1913. Kristiania, 1921, 

 p. 158. 



2 lUd., p. 64. 



