79 



Stations in nortb 

 Max. Min. Max. Min. latitudes. 



9311—24 11 5 h — 20 h 9 h — I4 h 20 h — 4 h Port Kennedy. 

 2411 7 h — 17 h 8 h 16 h Point Barrow. 



19 h 3 h — ll h 6 h 18 h — 20 h Polhem (Spitsberg). 



The opposite course is evident. The maxima in middle 

 latitudes correspond with the minima in the north and vice 

 versa. When west perturbations occur in the south, east per- 

 turbations arrive in the north. The perturbations have 

 changed signs. When the magnetic needle is deviated to 

 east in southern regions, it is deviated to west in polar- 

 regions. 



The cause of this opposite deviations cannot hardly 

 be an other than that the disturbing force lies between the 

 southerly and northerly regions. 



As it was mentioned above the north magnetic pole 

 of the earth is surrounded by a belt in which the yearly 

 number of auroras is in maximum. When we regard the 

 auroras as the effect of down- or uppwards flowing electrical 

 currents in the atmosphere, it results clearly that these 

 electric air-currents must occur in greatest number and with 

 highest intensity in the auroral maximum belt. Applying 

 the known rule of Ampere, we will find that a downwards 

 current in the maximum belt shall deviate the magneetic 

 needle to east in the north and to west in the south of 

 the belt. The fact is hereby simply and well explained, but 

 it remains to ascertain the existence of this current and to 

 measure it. 



These ends have been attained by a point-apparatus 

 constructed on mountains in Lapland. We have used such 

 point-apparatus of different size but it will be sufficient for 

 the reader if we describe one of them. It consisted of a 

 copper or iron wire of about 2 mm in diameter, provided 

 with brass needleformed points on every half meter. This 

 wire was laid out on insulators (porcellain or glass-vessels 



