PART II. POLAR MAGNETIC PHENOMENA AND TERRF.LLA EXPERIMENTS. CHAP. III. 



541 



COMPARISON OF STORMINESS AT THE FOUR STATIONS. 



104. In the following table is given the total storminess for the months December, January and 

 February, and the mean of the whole three months' period. S is the storminess expressed in relative 

 numbers, the total storminess of Kaafjord being put equal to one. 



6 is the angular distance to the magnetic axis. 



TABLE XCVII. 



The magnitude of the storminess follows in the order Axeloen, Dyrafjord, Matotchkin-Schar, and 

 Kaafjord. The two stations Axeloen and Dyrafjord with the smallest angular distance have the greatest 

 storminess. The storminess, however, is not quite symmetrically, arranged with regard to the magnetic 

 axis, for Kaafjord, with an angular distance of 24.7 has only about half the storminess of Matotchkin- 

 Schar with a still greater angular distance ; and both stations are situated to the south of the auroral 

 zone. Dyrafjord and Matotchkin-Schar have nearly the same storminess, although their angular distances 

 are greatly different. 



The relative stopminess of AxelOen is the most remarkable. Although the great storms have their 

 centres between Axeloen and Kaafjord, and generally quite as near to the latter station as the former, 

 the storminess at Axeloen is more than three times as great as that at Kaafjord. 



One possible explanation of the great storminess at Axeloen is, that besides the large storms with 

 their centres between Axeloen and Kaafjord, there are a number of smaller storms which have their 

 centres nearer to the magnetic axis. If so, we should expect the principal maxima of storminess which 

 are mostly due to the occurrence of large storms compared with the average storminrss of the stations 

 to be smaller for stations situated near the pole and the magnetic axis. 



The distinctness of the principal maxima is illustrated in the following table. 



TABLE XCVIII. 



The columns (I) correspond to the period of three months common to all four stations. The 

 columns (II) correspond to the whole period during which observations have been made at the various 

 stations. 



Birkeland. The Norwegian Aurora Polaris Expedition, 19021903. (J'J 



