370 laUKKl.AM). 1111 NoUWKOIAN AI'kORA I'OLAkls KXI'KI MTIUN, 1 9O2-- - I QO'}. 



positive polar storm developes, its effects also being at first apparent as far north as Cape Thordsen, 

 and at (iodtliaal). 



On Cape Thordscn and Jan Maven, that is to sav at the two stations situated to the north of the 

 auroral /.one, the conditions are a little more complicated, from the fact that later on, at about 16'', a 

 negative polar storm appears to break in upon the positive, which, in Cape Thordscn, it considerably 

 exceeds in strength, causing in consequence strong negative deflections in the horizontal-intensity curve. 



The negative storm that asserts itself here, also acts, and verv powerfully too, at Fort Conger, 

 where the deflections are strong! v marked. 



With regard to Jan Maven, the eflects o| the negative storm are not so apparent, parti v because 

 the effects of the positive sturm are verv strongly marked, and partlv because perhaps the area of pre- 

 cipitation of the negative storm is not so much in the immediate vicinitv of this station as of Fort 

 Conger and Cape Thordsen. The negative storm, when at its height that is to sav at about ry' 1 or 

 18'' - oiilv succeeds in almost neutralising the effect of the positive storm as far as the horizontal 

 intensitv is concerned. In declination and vertical intensitv, on the other hand, especiallv in the latter 

 component, then.- are verv marked deflections at the above-mentioned time. /', is in one direction all 

 tlu- time, and negative. This is what might be expected, as both the negative svstcm to the north, and 

 the positive svstem to the south, will cause deflections in a negative direction. The character of the 

 declination curve is more disturbed, and several powerful, bnel impulses occur, now in one direction 

 and now in another. 



The perturbations are evolving, when thus looked at as a whole, c.xaetlv in the same manner as 

 in the most tvpical of the cases we have alrcadv considered. 



It is moreover easy here to study the movements of the svstems, which stand out with peculiar 

 distinctness in the case of the negative svstem of precipitation. 



At Kingua Fjord, the wide deflections in the horizontal-intensity curve begin rather suddenly at 

 14'' 10'". At Fort Rae, on the other hand, the deflections at first increase more slowly, so that no 

 definite time for their commencement can be given. On looking at the horizontal-intensity curve, however, 

 we find a considerable difference in time, by comparing the beginning and the time of the maximum 

 deflection. It is a little doubtful how great this difference is, but we mav put it roughly at one hour. 



We cannot, however, take it for granted that the effects observable at these two stations are 

 those of one and the same system; but we obtain a better general idea from the charts. 



At I glaamic we also have a very characteristic deflection in //, which both begins and ends rather 

 abruptly. It is therefore easy here to determine a difference in corresponding hours. Compared with Kingua 

 1' jonl, there is a difference of about i' .> hours in the time of its commencement, while it ends only 

 about three quarters of an hour later than at Kingua Fjord. Between L'glaamie and Fort Rae there is 

 a distinct difference of about half an hour, observable both at the beginning and the end; and there 

 seems to be no doubt that this is the effect of one and the same svstem. The deflections in // are 

 here so powerful that the needle is outside the field of observation from 16'' 55" to [Q 1 ' 35'", except 

 at j8'' 25'" and i8 !l 30"', when readings have been taken. 



The next station at which the negative storm acts is Ssagastyr, where the deflections in // begin 

 about half an hour later than at L glaamie, ami are very sharp and distinct. A comparison, as regards 

 the time of the maximum, with Fort Rae, shows a similar condition, tin- difference being about one hour. 



The deflections in // do not decrease regularly until the conditions have once more become normal ; 

 but for two hours after about 19'' there 1 is a more or less constant perturbing force of about 150;'. 

 The character of the curve seems to indicate that there has been some defect in the instruments, and 

 that the needle in some way or other has become fixed; but as there are at the same time perturbing 

 forces in the declination, it is impossible to be sure of this. 



