— 230 — 



vector moves anticlockwise. He also ventures some sup- 

 positions on the cause of disturbance, which perhaps should be 

 attributed to a system of electric currents entering the surface 

 of the earth perpendicularly and rotating daily aiound 

 some pole, it may be tlie magnetic- oi' the aurora-pole or some 

 other pole. 



This paper gives the results of the investigation of the 

 daily held of disturbing force and its rotation discussed above. 



The history of magnetic science proves that wrong notions 

 on magnetic phenomena, as secular and daily variation, 

 disturbance etc. were cherished as long as these phenomena 

 were being investigated at one or a small number of stations 

 and that a true understanding has been obtained only by an 

 inquiry into the phenomenon at different points of the globe. 



Accordingly the first task was to derive the daily components 

 of disturbing force for a number of stations distributed as 

 widely as possible over the globe, and as well the horizontal 

 as the vertical ones. 



The material available is scant, the necessary dates for 

 quiet days failing for many stations, but we may expect that 

 the publication of the observations taken in the recent year 

 of antarctic exploration will enlarge it importantly. 



Hereafter information on the material used is given. 



The values of tlie horizontal component derived by Lüdeling 

 have been used without change; for the vertical component 

 the following quiet days have been taken into account : 



1888 

 ( June 4, 5, 10, 12, 15. 



Cape Thonhen July 3, 4, 12, 20, 21, 22, 23, 28. 



I August 4, 9, 10, 16, 17, 20. 



,.. ^. , June 4, 5, 6, 10, 11, 12, 15. 



^ -^ I July 3, 4, 12, 20, 21, 22, 23, 28. 



I June 4, 5, 15, 29. 



Novaja Semlja July 21, 22, 23, 28, 29. 



[ August 4, 9, 16, 17, 26, 31. 



