Geomagnetism— Knapp and Roberts 165 



of the field in the Arctic (8). The circumpolar field is dis- 

 tributed in an elongated pattern with the pole inexplicably 

 near one end of the area. The possibility of a second magnetic 

 pole to reconcile the disparity was advanced by Hansteen and 

 has lately been revived (6, 13). It is easy to see why the matter 

 remains in doubt, when we realize the tremendous problems 

 entailed in making magnetic observations in the heart of the 

 Arctic Ocean. Nevertheless, progress has been made and will 

 certainly be accelerated in this matter, in Alaska itself as well as 

 in areas lying within range of Alaska-based operations. 



The short-time fluctuations comprise a large and fruitful 

 area of study in geomagnetism, having numerous practical and 

 theoretical aspects. In this field, the important role of Alaska 

 was recognized long ago. Protracted schedules of observations 

 were maintained by Rochfort Maguire at Point Barrow during 

 his two winters there (1852-54) in connection with the search 

 for the lost Franklin Expedition (11), and the same place was 

 chosen for one of the two stations conducted by the United 

 States during the International Polar Year of 1882-83. Fifty 

 years later, two Alaskan stations were occupied during the 

 Second Polar Year of 1932-33— one at Point Barrow by the 

 U. S. Weather Bureau (2), and one at College, near Fairbanks, 

 by the U. S. Coast and Geodetic Survey and the Carnegie Insti- 

 tution of Washington (5). 



The daily variation and other transient phenomena, taking 

 their origin in overhead electrical activity, must reflect any 

 regional features of such activity (4). It was Sir Edward Sabine 

 who pointed out that the daily magnetic variation "is in fact 

 constituted by two variations superimposed upon each other, 

 having different laws, and bearing different proportions to each 

 other in different parts of the globe." The two constituents 

 are known today as the quiet daily variation, S q , S referring to 

 the solar day and q to a period of quiet magnetic conditions; 

 and the disturbance-daily variation, S d , the d of course referring 

 to disturbed conditions. 



The most striking of the differences in distribution lies in 

 the fact that whereas the quiet daily variation is weak through- 



