lO 



L. VEGARD. 



M.-N. Kl. 



The Nitrogen spectrum, then, should be formed when such minute 

 extremely cold (and electrically charged) dust particles of Nitrogen are 

 bombarded by cathode rays — (or perhaps other sorts of electric rays). 



If our view with regard to the state of the upper strata of the atmosphere 

 is right, I think we can understand why there is no Helium and Hydrogen 

 layer on the top of our atmosphere, for on account of the much lower 

 freezing point of these gases they may be unable to form clusters — and 

 as soon as a Hydrogen molecule or a Helium atom gets charged it wall 

 fly out of the atmosphere as a positive ray. 



Nitrogen dust 



Nitrogen gas 



'Oxygen . 

 qas Mrgon 

 -i+- — Urn. 



Fis:. I. 



Fie-. 2. 



Fig. I illustrates the composition of the atmosphere in accordance with 

 the old view. The composition and state of the atmosphere here suggested 

 is illustrated in Fg. 2. 



§4. 



Our hypothesis with regard to the state of the atmosphere gives us 



also a new possibility for explaining the change of colour of the auroræ. 



In previous papers we have already mentioned the tho following possibilities: 



i) A change of colour may be caused by the change of velocity of electric 



rays on their passage through the atmosphere. 

 2) A change of colour may be produced when the electric rays neutralise 



the charged particles in the atmosphere. 



But now there is also the possibility that the electric rays may cause 

 some of the Nitrogen dust particles to give off molecules, and these mole- 

 cules will produce the ordinary gas spectrum, which gives the reddish colour 



