V 



The consequence was that attempts were made to knit together all these new discoveries 

 and hypotheses into one cosmogonic theory, in which solar systems and the formation of galactic 

 systems are discussed perhaps rather more from electromagnetic points of view than from the 

 theory of gravitation. 



One of the most peculiar features of this cosmogony is that space beyond the heavenly 

 bodies is assumed to be filled with flying atoms and corpuscles of all kinds in such density 

 that the aggregate mass of the heavenly bodies within a limited, very large space would be only 

 a very small fraction of the aggregate mass of the flying atoms there. 



And we imagine that an average equilibrium exists in infinite space, between disintegration 

 of the heavenly bodies on the one hand, and gathering and condensation of flying corpusles on 

 the other. 



I cannot conclude this great work without expressing my warmest thanks to my numerous 

 assistants for their most able collaboration. If I mention them according to the number of years 

 in which they have faithfully helped me, I must begin with my good old friend, now dead, 

 schoolmaster DIETRICHSON, who for ten years continued to work every day at my side. In the 

 next place there are some young, energetic men, a few of whom have already begun independent 

 work - Mr. KROONESS, now manager of the Haldde Observatory, Mr. VEGARD, now a tutor at 

 our university, Mr. SKOLEM, a very skilful mathematician, and Mr. DEVIK, a capital experimenter. 

 Further Captain BULL, of the Norwegian Navy, and Mr. NORBY, have done a large amount of 

 calculation, and Mr. NATRUD and Mr. B. TOLSTAD, assistants at the Norwegian Geographical 

 Survey, have made many drawings. The translation of also the whole of this volume has been 

 done very satisfactorily by Miss JESSIE MUIR. 



Christiania; September, 1913. 



Kr. Birkeland. 



