PART II. POLAR MAGNETIC PHENOMENA AND TERRELLA EXPERIMENTS. CHAP. I. 353 



arrow, one might be tempted to believe that these were really systems of precipitation in which the 

 direction of the principal axis is not so decidedly east and west, but more north and south. It is easy 

 to imagine a connection established between such a system in Kingua Fjord, and the negative system of 

 precipitation at Cape Thordsen and Fort Conger. Such a condition is not only conceivable, but, as 

 previously observed, we find by the experiments, phenomena which clearly demonstrate that we should 

 expect to find, just in these tracts, areas of precipitation the main axis of which were directed tolerably 

 nearly due N S; compare p. 327, fig. 140, art. 82. 



The conditions at Godthaab and Jan Mayen in connection with the southern stations, show us 

 distinctly a positive system of precipitation with accompanying area of divergence. At Pawlowsk, as we 

 see, there are also positive vertical arrows; and we have already seen that at Gottingen, during this 

 period, a positive deflection appeared in the vertical-intensity curve. We thus have every indication of 

 the existence of this positive system of precipitation. 



These are in the main the most characteristic conditions during the first section of the perturbation. 

 It is difficult to prove with certainty any movement of the systems. 



At several stations there now ensues a longer or shorter period of more normal conditions, after 

 which the new perturbations belonging to the second section commence. At other stations there is no 

 such distinct division, but the deflections continue without ceasing on into the next period. 



The perturbation-conditions here prove to be rather more complicated than in the preceding section. 



We will here make Ssagastyr our starting-point. The perturbing forces appear here chiefly in the 

 horizontal intensity. The amplitude of the deflection is now about the same as during the preceding 

 section ; but its duration is here a little longer. No exact statement of the time of the appearance and 

 termination of the perturbation can be given, but roughly speaking, the perturbation occupies the period 

 from i6 h 30 to 20''. Simultaneously with this, the conditions at Uglaamie and Fort Rae are very inter- 

 esting, as we there find simultaneous deflections in the curves, especially in the horizontal-intensity curve, 

 in a negative direction; but the forces are now comparatively very weak. 



At the stations west of Ssagastyr, however, there are fairly powerful perturbing forces. As before, 

 we can follow the negative storm over Cape Thordsen and Fort Conger; and at the first of these 

 stations, the perturbing forces are of considerable strength. 



The conditions at Little Karmakul and Bossekop are now of special interest. At the first-named 

 station we again meet with a condition of which we have so often before had instances, namely, the 

 simultaneous action of positive and negative perturbing forces. We there find now positive, now nega- 

 tive deflections in the horizontal intensity, until about i8 h 30, from which time the deflections are 

 negative and remain so for the rest of the period. From this hour then, the effects of the negative 

 storm predominate, and the perturbing forces are exceedingly powerful, thus indicating the proximity of 

 a storm-centre. 



At Ssagastyr, we found, it will be remembered, exclusively negative deflections in the horizontal- 

 intensity curve, beginning at the very beginning of the period. 



At Little Karmakul, it is not until considerably later that the negative storm gains the ascendancy; 

 and this would therefore seem to indicate that the negative storm-centre, or district of precipitation, is 

 moving westwards. 



This last view of the conditions is also confirmed by a comparison with those at Bossekop. At 

 first there is evidently a positive polar storm acting, and we cannot perceive any special trace of a 

 negative storm. At about ig h 30, however, the curve for the horizontal intensity goes to the opposite 

 side, and for the rest of the time we find fairly powerful effects of a negative polar storm, although the 

 perturbing forces here are not so great as those we find at Little Karmakul. If we look at the time 



