the sun and chiefly conditioned by the actual, distance of the observing station 

 from the centre of the auroral zone. There seems, in fact, little doubt that aurora 

 would be seen almost continuously during the winter from a position a little to the 

 north-east of Cape Adare. Evidence for the pronounced daily variation in the 

 occurrence of aurorse has already been given, and there appears to be a great 

 probability that aurorse can be seen from some spot on the earth's surface at every 

 instant. 



Since magnetic storms are of comparatively infrequent occurrence at low 

 latitudes, we cannot expect to find a very close relationship between the occurrence of 

 aurorse at high latitudes and the incidence of magnetic storms of world- wide extent. 

 On the other hand, we know that there is a fairly close connection between such 

 storms and the appearance of aurorse at low latitudes. 



On Vegard's theory that the aurora is caused by rays projected from the 

 sun, and similar in every way to the rays which accompany radio-active dis- 

 integration, we can recognise that the normal path of each ray will be a spiral, 

 (the curve which represents the total of all these paths being the " auroral spiral ") ; 

 the time at which one portion of this spiral appears overhead at each station 

 is in the early morning ; there is a tendency for a second maximum to appear 

 overhead in the afternoon, and this tendency does not appear to be quite a normal 

 one. 



If the particles causing the aurora are alpha particles due to radio-active changes 

 taking place in the sun, we must also recollect that a series of radio-active changes 

 will be accompanied by beta and gamma rays, also projected from the sun.* Both 

 of these are more penetrating than alpha rays, the former being negatively charged 

 and more easily deflected in a magnetic field, and the latter being short wave radiations 

 which are not so deflected. 



Aurorce and Magnetic Disturbances. 



It has long been known that, in low latitudes, there is a direct relation between 

 auroral phenomena and magnetic storms. 



Though at low latitudes, auroral displays are accompanied by magnetic storms, 

 this is by no means always the case in high latitudes, and as Dr. Chree has pointed 

 out in the Magnetic Report of this Expedition, the same holds true at the Cape Evans 

 station. 



Dr. Chree has, however, shown that, on the whole, the magnetic character of the 

 hour is definitely related to the brilliancy of the aurora during that hour. This 

 result is of great interest and demands the fullest investigation. 



* The projection of particles bearing positive and negative charges in significantly equal numbers is 

 a necessary condition, as pointed out by Vegard. 



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