IV 



Besides making clear the origin of important terrestrial phenomena, the investigations give 

 promise of the possibility of drawing, from the energy of the corpuscular precipitation on the 

 earth, well-founded conclusions regarding the conditions on the sun. 



The disintegration theory, which has proved of the greatest value in the explanation of the 

 radio-active phenomena, may possibly also afford sufficient explanation as to the origin of the 

 sun's heat. The energy of the corpuscular precipitation that takes place in the polar regions 

 during magnetic storms seems indeed to indicate a disintegration process in the sun of such 

 magnitude, that it may possibly clear up this most important question in solar physics. 



Future researches in the paths here entered upon, which I believe will lead to the solution 

 of some of the most attractive scientific problems of our age, e. g. the origin of terrestrial 

 magnetism, and the origin of the sun's heat, may be carried out upon a far wider basis than I 

 have been able to employ, without making the expenses connected therewith too great a deterrent. 



In 1Q02 1903 I had the great good fortune of having twenty-five observatories with me; 

 but on a future occasion it will be necessary to have double the number. 



We should then have to send out small expeditions with, say, ten stations suitably distributed 

 about each of the magnetic poles, and make sure of getting magnetic registerings for the same 

 period from all the observatories in the world. 



As the position of the stations, within certain limits, may be chosen with tolerable freedom, 

 the end would be best attained by accompanying whalers, or, as I once had to do, equipping 

 such vessels one's self for certain places. 



The mathematical investigations, which, together with my experiments, are intended to make 

 clear the movement of electric corpuscles from the sun to the earth, have been carried out, with 

 a perseverance and ingenuity worthy of all admiration, by my friend, Professor STORMER, who will 

 publish the complete results of his investigations in a special part of the present work. These 

 results, however, will be known to some extent from the papers he has already published. 



In concluding this first section, I have to thank those persons who have so greatly assisted 

 me in my work. In Mr. L. VEOARD I have had an invaluable collaborator, whom I have to thank 

 for many excellent suggestions. Great merit is also due to Mr. DIETRICHSON and Mr. KROGNESS 

 for their share in this work; and I would further thank Messrs. RUSSELTVEDT, NORBY and IRGENS, 

 for their energetic labour. 



The translation, which I consider very successful, has been performed by Miss JESSIE MUIR. 



Christiania; October, 1Q08 



Kr. Birkeland. 



