BIRKKI.AM). Mil: NOUWKIilAN AURORA I'OI.ARIS KXI'K] >l TION, I QO2 1903. 



As will l>c seen from the picture, the areas of precipitation form a distinctly spirally shaped belt, 

 winding np\\ arils towards the magnetic pole. 



'1'he upper part of this spiral belt always appears sharply and clearly defined, sometimes as a 

 more isolated patch, sometimes, as in this instance, this patch appears in connection with an elongated 

 adherent polar belt. The patch comes out very plainly in the first and third plates, as an oval shaped 

 figure of light within the long spiral belt. This patch does not alter its place much for different posi- 

 tions i if the terrella in relation to the cathode, and it exists under all degrees of stiffnesses of the 

 cathode rays. The remainder of the polar belt is, on the other hand, more variable in its formation. 

 According as the magnetic and electric conditions are altered, this belt undergoes severe changes. At 

 times the whole is continuous, as on the plate here, at other times several well defined figures of light 

 can be found, and at times the whole can almost disappear. As regards further details, we must, how- 

 ever, here confine ourselves to referring to a subsequent chapter, in which the terrella experiments 

 are described and in which the tangential direction of the rays nearest the earth in various parts of the 

 area of precipitation are examined. As will be found there, we have also further succeeded in showing 

 that the cathode rays, close to the terrella, arc bent in a manner which in the main features exhibits 

 the most complete analog\ r to the characteristic systems of precipitation on the earth which we constantly 

 meet, I!y fixing screens at suitable places, it has likewise been possible to show that the rays which pre- 

 cipitate themselves in the luminous polar belts on that side which corresponds with the afternoon side in the 

 vicinitv of the terrella will be bent off towards the west -and thus corresponding rays will have magnetic 

 actions on the earth as a current towards the east -while the other rays, especially on the night side, 

 will be bent in the opposite direction, i. e. towards the east; to the north and south we must then 

 imagine the direction respectively to the south and north poles of the terrella magnet. We thus find a 

 clearly evident analogy between the actual conditions and the experiments. 



The analogous system of corpuscular rays, which we imagine around the earth, will thus, by the 

 rotation of the earth, in the course of a day be moved round, at the same time its shape will be some- 

 what changed owing to the sun's altered height above the magnetic equator. The only part which never 

 disappears is the marked patch near the axis. 



If we now assume that Kingua Fjord is situated just at that part of the earth where the system 

 of precipitation corresponding to this patch is passing, we seem to get a natural explanation of the 

 peculiar phenomena we observe here. 



(1) In the afternoon, Greenwich time, which would be noon and afternoon local time, strong varia- 

 tions in the magnetic elements constantly occur; this corresponds with the light patch always being 

 visible, and thus every day the corresponding system will pass the spot. 



(2) That the direction of the current-arrows is frequently pointing southwards, agrees with the 

 luminous belt in the innermost portion nearest the pole swinging strongly northwards or southwards. 



13) I Hiring a later perturbation, i^th December 1882, we find at Kingua Fjord for a prolonged 

 period polar precipitations, while none such made themselves distinctly noticeable at the other stations. 

 1 his accords with the system corresponding with the luminous patch also occurring simultaneously with 

 the equatorial ring - compare fig. 37 Part I. 



At the third hour given on Chart III, J 6' 1 20'", perturbations of no inconsiderable magnitude have 

 developed at all the stations. 



At Ssagastvr and Cape Thordsen, a negative polar storm is now distinctly acting, a storm that is 

 also continued round the geographical pole to Fort Conger, Kingua Fjord, Fort Rae and L'glaamie. 



On the afternoon side, moreover, south of this negative system, we have the effects of a positive 

 system in the district embracing (lo Ithaab, Jan Mayen and Bossekop. Little Karmakul is situated, as 



