PARTI. ON MAGNETIC STORMS. CHAP. III. 211 



in a region not far from Stonyhurst. Whether there is an area of convergence on the other side of 

 the world, we cannot say, as there is no material from those regions. 



The intermediate storm, like the corresponding one on the i5th February, is particulary powerful 

 at Axeleen and Matotchkin Schar, and probable less so at Kaafjord as far as we can see from the curve, 

 which at this time has disappeared from the magnetogram-paper. The current that conditions the per- 

 turbation seems therefore now be near our north-eastern stations. The duration of this storm is also 

 about the same. In Central Europe and southwards to Batavia, its commencement and termination are 

 well characterised. It occurs between I5 h 30'" and i6 h 45. The corresponding storm on the I5th 

 February lasted from i6 h I5 m to 17'' 45 m . 



In the eastern hemisphere a decomposition has been undertaken, the result being shown on 

 Charts IV, V, and VI, at i6 h , i6' 1 20, and i6 h 30"' respectively. 



Throughout the western hemisphere, with the exception of Sitka, the perturbation is somewhat less 

 powerful than in the eastern. The effect in the United States is principally noticeable in H, showing that 

 the current-arrow for the intermediate storm would be directed westwards. As these however are very 

 small, we have not marked them on the charts, but only drawn the current-arrows corresponding to the 

 total force. The eastern field in this storm is of about the same form and proportional strength as that 

 of the 1 5th February. The current-arrow in Europe points south-east, and turns off towards the east 

 through southern Asia. As Zi-ka-wei it even goes a little north, so that there is a good indication that 

 the current-lines here form an en entire circle, as they return in the regions round the Norwegian sta- 

 tions, where the arrows are directed westwards along the auroral zone. On the western hemisphere, on 

 the other hand, there is certainly an area of divergence, with, it appears a weaker perturbing force. 

 The field in the intermediate storm is thus of the same character as that found in the polar elementary 

 storms. This also applies to the northern stations. 



At Matotchkin Schar and Axeleen there is a powerful perturbation with current-arrows directed 

 westwards. The vertical intensity at Matotchkin Schar is very great, and is directed upwards; at Axel- 

 een the balance moves up and down about its mean position. At first P, is directed downwards, but 

 in less than a quarter of an hour it has changed, and is directed upwards, after which it changes once 

 more. There is the same variableness in P, on the I5th February, but on that occasion it begins by 

 being directed upwards. At Kaafjord, both now and on the isth February, the conditions are more in 

 accordance with those in southern latitudes, the arrow being directed towards the south-east. The circum- 

 stance of the current-arrow at Kaafjord having almost the opposite direction to those at the two north- 

 eastern stations, is also found on the 15th February, and its probable explanation we assumed, in the 

 description of that perturbation, that there was a precipitation on the day side. 



For this storm there are unfortunately no registerings from Dyrafjord; they would have been of 

 very great significance. 



The second section. 2i h 40" -- about midnight. 



The polar storm from 2i b 40 to about midnight is very powerful round the Norwegian stations. 

 Its beginning and end are fairly distinct; it is well defined and simple in its course. This time, too, the 

 changes in the perturbation are most rapid at Axeleen, where the conditions on the whole are more 

 disturbed. This storm manifests itself by simultaneously-occurring perturbations, that are observable all 

 over the northern hemisphere. The table below gives the time at which the storm begins, reaches its 

 maximum, and ends, as also the maximum value of P,. 



