PART 1. ON MAGNETIC STORMS. CHAP. II. 



Current-Arrows for the 15th December, 1902; Chart VII at 2h 45"", 



93 



Fig. 44. 



Chart I shows the conditions at i' 1 , or about the time when the perturbing force for Dyraijord 

 has its maximum ; and we see that it has a direction characteristic of this place, namely south of west. 

 At the other Norwegian stations, the perturbing force is small at the same time, notwithstanding that 

 these stations are situated about the line of direction of the current-arrow at Dyrafjord. We notice 

 further that the current-arrows at these three stations converge towards one point. 



Taking the European stations, the current-arrows show that the perturbing force for San Fernando 

 at this hour has a north-westerly direction, while farther north it goes almost due west. As far north 

 as Pawlowsk, its direction is WSW, and at Bossekop SW. 



The perturbing force at Toronto, Cheltenham and Baldwin, is directed towards the SE, as is 

 usual during those polar storms which are especially violent at the Norwegian stations. At Sitka, its 

 direction is S. We notice that the arrows for these four places appear to issue from the same spot at 

 the south point of Greenland. 



Chart II. Time / h // m . 



The conditions as a whole are the same as in Chart 1. The force has increased in strength at 

 Axeleen, and decreased at Dyrafjord, while the directions are the same. In the mean time P, at 

 Dyrafjord has changed its direction. 



The arrows for Sitka and Baldwin, and still more for the European stations, have turned a little 

 in direction from the left towards the right. This direction we will designate as the positive direction. 



