3QO 13IRKELAND. THE NORWEGIAN AURORA POLARIS EXPEDITION, IQO2 1903. 



The second main section of the powerful perturbations on this date, is, as we have said, from 

 ig h 45 to the end of the period. 



At about i9 h 45 m , it appears that comparatively quiet conditions have once more supervened at 

 almost all the stations. At a few of them the conditions are almost normal for a short time; at others 

 we find a more or less marked minimum in the deflections; while at others again there appears to be 

 a transition, as the storm, which was previously positive, now changes to negative. 



That which characterises this second section of the perturbations, is the powerful negative polar 

 storms which we find at all the stations. These are certainly only to be considered as a further 

 development of the earlier negative systems of precipitation observed. In the deflections at Kingua Fjord 

 at this time, there is a minimum of no great distinctness. The declination-deflections, which have 

 previously continued to be quite strong, have shown a slight indication of a minimum at about i9 h 45; 

 while the horizontal-intensity curve, which, since about jy 11 has been more or less evenly approaching 

 the normal line, has now reached it. The horizontal intensity then remains almost normal for a couple 

 of hours, only oscillating slightly about the normal line. 



The conditions at Uglaamie form a suitable starting-point for our reflections upon the perturbations 

 in this section. There are, as will be seen, two strong deflections separated by an interval in which the 

 deflections have a brief, but very marked, minimum just before 2i h . These two deflections are so strong 

 that in both cases the needle passes out of the field of observation. 



To the first of them, there are corresponding deflections at Ssagastyr and Fort Rae, as also at a 



number of other stations, although, the resemblance at some of them, is less marked. At Fort Conger 



the resemblance is quite striking. At Little Karmakul, there are also two maxima, which show some 



resemblance to those at Uglaamie; but the resemblance between the first pair of them is not so great. 



It has more the appearance of a brief but powerful impulse, a precursor of the subsequent strong deflection. 



The storm thus appears as a negative polar storm; with its centre in the vicinity of Uglaamie. 



On Charts IV and V there are two hours which represent the conditions during this first phase 



of the second section. There are fairly powerful perturbing forces at several stations. 



The different systems that we here see are, of course, connected in some way or other with each 

 other; but it seems as if the system in the neighbourhood of Uglaamie was more or less independent. 

 It is therefore very likely that there is a large, more or less connected, negative system of precipitation, 

 in which there are two storm-centres, one in the vicinity of Uglaamie, and the other in the region east- 

 wards from Kingua Fjord. 



The hour 20'' 30 on Chart V, also belongs to this first phase of the perturbations. We here 

 see the conditions at the time of the strong deflection at Little Karmakul. 



The negative system of precipitation now also forms a circle round the geographical north pole, 

 and the forces seem to be concentrated about several storm-centres. There still seems to be one at 

 Uglaamie, one at Little Karmakul, and one less powerful one at Kingua Fjord; but whether they are in 

 reality so clearly separated as they appear to be, it is difficult to say. 



We find here no distinct traces of positive systems, although it is possible that such do actually 

 exist, and from what we have seen, are to be looked for to the south, or in the southern part, of the 

 auroral zone, from Europe westwards; but we have no stations there. 



A distinct, though rather faint indication of such a system is to be found indeed in Jan Mayen at 

 about 20'', and the rapid transition from Little Karmakul to Bossekop, found on Chart V, for the hour 

 2O ii 30, is possibly due to the existence of positive polar precipitation to the west. The direction of the 

 current-arrow at Gettingen, which is a little more westerly than might be expected if the negative 

 systems only were acting, may also possibly indicate the existence of a positive system of precipitation 

 such as this. 



