PART II. POLAR MAGNETIC PHENOMENA AND TERRELLA EXPERIMENTS. CHAP. I. 355 



the positive system of precipitation that we find in the district Godthaab, Jan Mayen and Bossekop. At the 

 more easterly station Pawlowsk, on the other hand, the curve for the horizontal intensity oscillates more 

 about the normal line, without exhibiting any marked direction. It appears therefore as if the effect of 

 the positive system of precipitation were weaker here, which is quite natural, seeing that we are 

 approaching the negative storm-centre. 



Later on, it is the deflections in the declination -- which are easterly all the time -- that pre- 

 dominate. This, as we have often seen before, is a circumstance that has to do with the moving into 

 these southern districts of the negative system's area of convergence. We should also find the same 

 direction of current in the eastern part of the area of divergence, which is connected with the positive 

 system of precipitation. Of these two systems, which of course may be imagined to co-operate, the first 

 will here have the greatest effect. 



The course of the vertical-intensity curve at Pawlowsk also seems to indicate although one 

 cannot here venture to draw very certain conclusions -- that at first it is in an area of divergence, 

 where P, is positive, and afterwards in an area of convergence, at the time when we find negative 

 values of P, there. The course of the vertical-intensity curve at Gottingen exhibits similar conditions, 

 but there they are still more uncertain, as the normal line is very difficult to determine. It would not 

 therefore be advisable to draw any conclusions from this. 



With regard to the vertical intensity in other respects, it may be noticed that in Jan Mayen there 

 are negative deflections all through the section, with the exception of the last few hours of the period. 

 This is what we have found previously, and indicates that there is a negative precipitation to the north 

 of the place, or a positive precipitation to the south, or both simultaneously. At Bossekop we first have 

 positive deflections, as long as the positive storm is acting; and this should indicate that the positive 

 system is situated to the north of the place. Simultaneously with the alteration in the horizontal intensity 

 curve, there is also an alteration in the curve for the vertical intensity; and from the moment when the 

 negative storm gains the ascendancy, we find negative values of P, for the rest of the period. It would 

 seem, from the above, natural enough that the conditions should actually be in accordance with this. 

 At Sodankyla, on the other hand, we find the exact opposite; and we thus again meet with that 

 peculiar phenomenon, to which we have several times drawn attention. 



If the vertical-intensity observations at Cape Thordsen are to be relied upon, the negative system 

 acting there should at first lie to the north of the place, but in the last part of the period to the south. 

 This agrees very well with the conditions at Bossekop, as the supposed passage of the system over the 

 station at Cape Thordsen, at the time when P, there goes over from a negative value to a positive, 

 takes place just when the negative storm gains the ascendancy at Bossekop. Thus at the time when the 

 vertical intensity at Cape Thordsen indicates that the negative system of precipitation is approaching 

 Bossekop, we really find there marked effects of a negative polar system. 



This gives us a clear hint of the way in which the movement of the systems of precipitation up 

 there are to be understood, and seems to confirm our previous assumptions in the matter. We found, 

 it will be remembered, a removal of the system of precipitation towards the west, when we looked at 

 the three stations Ssagastyr, Little Karmakul and Bossekop, which were all situated south of the auroral 

 zone. No similar movement, however, could be traced to Jan Mayen, and we adduced, as a possible 

 cause of this, the circumstance that magnetically considered, that island had a comparatively much more 

 northerly situation. We further indicated that the conditions in Jan Mayen might possibly be explained 

 by assuming that the system at Cape Thordsen was moving westwards. We see now, however, that at 

 these hours there are also indications that the system at Cape Thordsen has a southerly movement, or 

 at any rate that its movement will have a component in a southerly direction; and it therefore seems 

 fairly probable that the change will take place a little earlier in Jan Mayen than at the more southerly 

 situated Bossekop. 



