r,iKKKLAM>. i in: NOKWKI.IAX .M'KI>KA POLARIS F.xi'F.mno.\, igoa -1903. 



In tin: first section we found the most powerful perturbing forces at Fort Rac, indicating the prox- 

 imitv to that station ol a storm-centre. 



This storm-centre was then situated to the east of Uglaamie. Now, in this last section, it is situated 

 to the \ve.-~t of it; and the conditions at that station during' these two perturbations, are in the main ex- 

 actlv similar. 



It' we look at the time of the appearance of the two perturbations, we find that the first takes 

 place just about as long before the passage of the sun through the meridian of the magnetic axis, at 

 about if)' 1 .50"', as the second perturbation does after it. In the description of the preceding perturbations, 

 we also pointed out a similar circumstance; but it was not arranged quite so symmetrically with regard to 

 the time tor the 1 sun's passage through the meridian in question, as on the present occasion. As regards 

 the. positive storm, the position of its centre cannot be so directly determined, as no district can be pointed 

 to, about which the forces evidently concentrate themselves. 



As regards the southern stations ; we find there too, simultaneously with the powerful polar storms 

 at about i8 h , a distinctly-defined perturbation, which, at Christiania and Gottingen, is particularly strong 

 in the declination; while at I'awlowsk the- deflections in horizontal intensity and declination are about equal. 



In the vertical-intensity curve for Jan Mayen, we notice a particularly characteristic, well-marked 

 deflection in a negative direction. It increases at first fairly evenly, but comparatively quickly, reaches 

 a maximum at al>ou f 18'' 30"', and then once more decreases rather more slowly until about 22'', when 

 the conditions are almost normal. 



Almost exactly the same thing is found at Little Karmakul. 



At the intermediate stations, Bossekop, Sodankyla and C'ape Thordsen, on the other hand, the 

 conditions are somewhat different. At the first-named station, the forces are of comparatively smaller 

 strength, and the deflections there are first positive, then change and become negative, after which, for 

 the remainder of the period, the curve oscillates over and under the normal line. At Sodankyla the 

 order is reversed, negative deflections coming first, then positive, and then small deflections, now in a 

 positive, now in a negative direction. 



At Cape Thordscn, the course of the vertical-intensity curve is peculiar. We there find, at the time 

 when the storm is at its height, very strong but brief impulses, now to one side, now to the other, but 

 more often in a positive direction. Later on, when the storm has diminished in strength, we find first 

 a negative deflection, then for a time fairly normal conditions, and then finally, at the end of the period, 

 positive deflections. 



In what way these conditions in the vertical intensity are to be interpreted will best be learnt by 

 looking at the charts, which show the perturbation-conditions for this section. 



The last four charts, /' t<> I' 1 1 1. for the hours //'' 211'", //' ./</'", /<?'' 20'" and /(/ 20'", represent the 

 conditions as they developc during this period. 



On Chart Y, the most powerful storms have not yet begun. \Ve see the negative system of preci- 

 pitation, which extends in a ring round the north pole. 



\Ye now find the strongest perturbing forces at Ssagastvr and Kingna Fjord. The conditions at 

 Cape Thordsen, Fort Kae and Uglaamie, seem, however, to indicate that there can hardly be several 

 sharply-divided systems of precipitation in the negative storm, but that the whole must be regarded as a 

 more or less coherent phenomenon. The succeding charts show this even more distinctly. 



A positive system of precipitation also appears quite distinctly at Godthaab. At Bossekop, Sodan- 

 kyla and Little Karmakul, at which, together with Jan Mayen, we have also seen effects of the positive 

 polar storm, the direction of the arrows is easterly, but the arrows are small. 



At the three southern stations, the current-arrows have a south-easterly direction, at the two west- 

 ern of them a little more south, and at I'awlowsk a little more east. These 1 conditions indicate that the 



