PART I. ON MAGNETIC STORMS. CHAP. II. 



7 1 



stations. At i6 h 45'", the perturbation on the whole has greatly increased in strength. We now have 

 very powerful perturbations at our Norwegian stations. We recognise the form of field as the typical 

 one for the polar elementary storms. The current-arrow in the storm-centre is now directed eastwards 

 along the auroral zone; and in the district of Europe and North America, the field forms an area of 

 divergence. 



Chart V; 77* o m . 



The field in southern latitudes has mainly the same character as at i6 h 45 m ; but at the Norwegian 

 stations the conditions have changed. 



At Dyrafjord and Kaafjord we still have a current-arrow directed eastwards along the auroral 

 zone; but as regards Kaafjord, the force is considerably less. At Axeleen, where we now have registerings, 

 the conditions are of a character altogether different from those of the two first-named stations. The 

 current-arrow at Axeleen points almost due west. This indicates that the perturbations here must be 

 of a somewhat local character. At Matotchkin Schar the direction of the arrow is reversed, and is now 

 almost exactly opposite to that at Kaafjord. This indicates the existence of a new storm-centre, which 

 is advancing from the east. These districts to the east of Matotchkin Schar are now upon the night 

 side, and we find moreover that the current-arrow about the storm-centre af this system is directed 

 westwards along the auroral zone. 



Chart VI. 



In lower latitudes the field is almost unchanged, except at Sitka, where a remarkable difference 

 occurs. The conditions at Dyrafjord and Kaafjord are much the same as before; while at Axeleen 

 and Matotchkin Schar the force has turned. 



We see that this storm has a tendency to form a field similar to that described for the polar 

 elementary storms. The circumstances are not, however, of the simplest. There is no doubt that we 

 have to do with several simultaneous polar precipitations of electric corpuscles. 



TABLE XII. 

 The Perturbing Forces on the gth December, 1902. 



