1916. No. I. ARE THE SOLAR CORPUSCLE RAYS NEGATIVE OR POSITIVE? 21 



What would now happen on the earth if suddenly all the stift' 

 corpuscIe-raNS which we supposed gave rise to a subtropical climate in 

 northern Europe, were taken away? If the sun suddenly, b}' its magnetism, 

 forced all corpuscle-rays to circulate round it at a small distance, the 

 polar regions of the earth would be very much cooled, and it is even 

 possible that the sun's radiation of light and heat would be considerably 

 diminished, supposing the >dusky veil« was getting thicker. 



According to the calculations made by Pickering, Wilson, Schuster, 

 \'oGEL. Seeliger and other astro-ph\sicists, the dusky veil should at present 

 absorb an important fraction (' 4 to ^;^) of the sun's light radiation, so that 

 any augmentation in the absorption would easily be felt on the earth. 



When in the way mentioned above polar regions of the earth were 

 much cooled, a great distillation from the previously heated ocean waters, 

 especially from the equatorial regions, would take place, bringing the pre- 

 cipitation necessary for the enormous ice formations at the poles. 



If therefore we could accordingly assume that the magnetisation of 

 the sun underwent periodic changes in intensity, we should undoubtedly 

 be able to give a plausible explanation for the consecutive glacial epochs 

 with intervals of mild climate on the earth. 



One could of course obtain nearly similar climatic variations by sup- 

 posing that it was the stift'ness of the corpuscular rays that unden\ent 

 periodic changes and not the magnetism of the sun. It is, however, cer- 

 tainly more natural to consider our first supposition as the primarx' cause. 

 In reality the stiffness of the rays will also in all probability- change when 

 the solar magnetism changes. 



Finally it might be argued on the other side that the primary cause 

 was not to be sought on the sun but in periodic changes in the magne- 

 tism of the earth. As we have clearly demonstrated in the preceding 

 pages, the width of the auroral zone on the earth is highly dependent on 

 the intensity of the magnetism of the earth. 



With three times as high magnetisation as actually exists, practically 

 no helio-cathode rays of stift'ness H o = 3 X 10'^ would come down into 

 our atmosphere, and on the other hand, if the magnetism of the earth 

 were to become three times less than it is now, these rays would penetrate 

 very deeply and over an area 12—14 times greater than now round 

 the poles. 



Now it is obvious that the magnetism of the earth has certainly under- 

 gone very great changes since the early Tertiary time, because there have 

 been other radical changes on the earth in the same period. But in my 

 opinion it is most natural to seek the primary cause of the climatic 



