( 784 ) 

 The registration of both nights together gives : 



From these nnmbers we also find the initial increase of the 

 earth-current amplitude for the (half) duration smaller than about 

 0.7 min. just as it was found for the currents Batavia — Cheribon 

 and Batavia — Anjer. 



For the difference in phase was found out of 14 cases, Semarang — 

 Cheribon 17°.5, Semarang — Soerabaja 16°7, whilst for Batavia— 

 Cheribon formerly 22° wns found. 



So the registration at Semarang furnished a highly important con- 

 firmation of the results found for Batavia — Cheribon. And jet no 

 conclusion could as yet be drawn for an influence of the distance 

 on the amplitude. 



And indeed, new observations made at Batavia soon offered 

 another view upon the subject. I heard that a connection with 

 Semarang was possible at the same time along lines through the 

 Northcoast plain and along the line already used round the South 

 by the railroad. 



Registration with these lines running between the same earthplates 

 at Semarang and Batavia (observatory) gave the remarkable result 

 that the current in both lines was unequal. 



The Northline corresponded with results found before on the 

 Bata\ia — Cheribonline, the Southline gave again the heightened increase 

 of the earth-current amplitude when the duration of the oscillation 

 decreased. 



Duration of half Am plitude Earth-current in Volt p erK.M. Number of cases 



an oscillation X Amplitude magnetic component in dynes 



Southline Northline 



50 min. 62 28 20 



0.77 48 29 20 



1.53 50 34 '20 



5.53 24 27 2C 



8. GO 23 27 'jO 



21.77 13 20 1- 



