( 530 ) 



The ratio c' between the secondary and primary part increases 

 with the frequency of the vibrations of the current. 

 Let us call the magnetic force X, then 



X = primary -\~ secondary 

 X =^Y\ma,ry {1 -\- c'), 



X 



so the primary part of Aq = ;. 



1 -f c 



t 

 The extra-terrestrial current which we can put S^=ssin27t- 



will induct in the upper earthstrata a current S' : 



S = Qf{ST)^cos2:t'-, 



The induction will depend on the distance and the latter possibly 

 on intensity and duration of the vibration of the current, moreover 

 on the conductivity q of the upper earthstrata. 



The primary magnetic force will at first approximation (the distance 

 being about the same) depend in the same manner on the extra- 

 terrestrial current. So : 



and 



t 

 ^,=f{sT)sin27t- 



X = {\^c')f{sT)sin27t~. 



The existence of a vertical conducting current having been proved 

 we must also take for granted that part of the extra-terrestrial current 

 is closed by the earth and .that a current is generated equally directed 

 as the current of induction. 



Already the properties of the conductivity of the atmosphere point 

 to a dependence of magnitude and duration of the extra-terrestrial 

 current, also on the conductivity of the upper earthstrata. 



So we put for the current 



t 

 ^ip {sT) sin 2jr — . 



And for the total current we find : 



or 



-^ f{sT) cos 2.-T ^ + if> isT)sin 2.t |, 



A — 



p 



v^' (•^7') + ^r c^^) 



'/^ . 2rT/ T fisT)?sr\ 

 sin — k H ±{q to — , 



