74 



In Sodankylä the E— W current shows two maxima 

 and two minima of whicb the former occurs with an inter- 

 val of 12 hours and also the latter, but the first max. arri- 

 ves only two hours before the first min., the second on the 

 contrary 5 hours sooner. In Pawlowsk appears only one 

 max. 8 h a. m. which corresponds with a max. 7 h a. m. in 

 Sodankylä, whereas the min. i Pawlowsk does not corres- 

 pond with either of the min:a in Sodankylä. 



4:o ,,The great variations in the earth-currents are 

 alvays accompanied by variations in the earths magnetisme", 

 which is the case at both stations. 



In the divisions number 5° and 6° Mr Wild treats the 

 question, evoked by Airy, that the earth-currents can be 

 regarded as the prirnary causes of the magnetic pertur- 

 bations and of the delay of these latter. 



In consequence of his observations Airy, as above men- 

 tioned, brought forward the follow r ing conclusions. 



,,a) It is impossible to ascribe to the earth-current the 

 principal part of the earth magnetism. 



b) It is not certain if the cause of the daily variations 

 can be ascribed to this current. 



c) Considering the conformity of the curves, repre- 

 senting the both phenomena, it is impossible not to draw 

 the conclusion: that the magnetic disturbances have their 

 cause in the galvanic earth-currents beneath the magnet. 



d) The variations in the earth-currents are more nu- 

 merous than in the earth-magnetism. 



e) The variations in the earth-currents occur before the 

 changes in the earth-magnetism viz, the variations in the 

 earth-magnetism are delay ed". 



All these results have heen verified both in Pawlowsk 

 and Sodankylä. By an inexplicable circumstance Airy had 

 found the time of delay much too long, but from the ob- 

 servations in Pawlowsk and Sodankylä this interval is of 

 about 5 minutes. 



In the first part of this paper, we have endeavoured 

 to suggest to the reader the idea that the earth is au elec- 



