6i8 



BIRKELAND. THE NORWEGIAN AURORA POLARIS EXPEDITION, 1902 -1903. 



Fig. 224. Nebulous ring, with the Earth for its centre, according to Jones. 



luminous and is capable of ... ; ...';::':;: 



absorbing and scattering solar . ; ..-.':; : ':\-i ; /;>^i 



light. When treating of the 

 formation of the tails of comets, 

 we come back to the same idea. 

 Possibly krypton, which seems 

 to cause the well known auro- 

 ral line in the auroral spec- 

 trum is thus emitted from the 

 sun, and that we may be 

 able in this manner to answer 

 a question put by RAM- 

 SAY( ! ): "Is there any process 

 which will tend to increase the 

 relative amount of krypton in 

 the upper regions of the atmo- 

 sphere?" 



120. We now return 

 to the radiations emanating 

 from the sun. From my 

 experience obtained from 

 the experiments, I regard 

 it as very possible from a 

 physical point of view, that 

 a ring of radiant matter 

 has been formed round the 

 magnetic equator of the 

 sun, the dimensions of this 

 ring being greater than 

 those of the earth's orbit. 

 We must recollect that in 

 the case of the sun, it is 

 a question of corpuscular 

 rays of very great stiffness, 

 as the mathematical calcula 

 tions also have shown. I 

 assume that these corpuscu- 

 lar rays from the sun 

 partially consist of atoms 

 and molecules, and not 

 merely of electrons, thus 

 that the radiant matter in 

 thick layers is both slightly 



(') RAMSAY: The Aurora Borealis. "' 



Essays Biographical and Chem- 

 ical p. 314. London 1908. Fig. 225. Space round the Earth into which the radiant matter from the Sun does not enter. 



