( 783 ) 



liave sometliing to do with it and that a registration of the current 

 at Semarang going over the distances Semarang — Cheribon and 

 Semarang — Soerabaya would probably be able to enlighten us in that 

 respect. 



This idea I have, indeed, been able to realize by a visit to Se- 

 marang in the month of December 1907. At the Post- and Telegraph 

 Office they kindly accommodated me for some days with a room 

 where I could place the instruments used at Batavia. Though I had 

 some delay by a slight accident, yet I could get excellent diagrams 

 during two nights. 



The result was defmite, viz, the current between Semarang — 

 Soerabaja and Semarang — Cheribon corresponch in character and 

 intensity to that between Batavia — Cheribon. 



Oscillation 



of the magnetic 



North component. 



Half 



Amplitude of the earth current in Volt per K.M, 

 Amplitude magnetic component in dynes. 



Sem.-Cheribon Sem. -Soerabaja Batavia-Cheribon 



Found Number 



oscillation Amplitude 18-19 December 1907. 



0.5 min. 1.2 y 22.6 19.3 



1.0 „ 1.5 ,; 20.9 16.9 



13.5 „ 3.0 „ 16.2 14.4 



formerly, of cases. 

 21.2 14 



20.5 11 



16.0 8 



19—20 December 1907. 



0.6 min. 0.5 y 26.3 23.6 23.0 33 



1.4 „ 1.1 „ 23.4 20.0 20.5 16 



9.5 „ 2.4 „ 20.3 16.7 16.5 19 



So: 



53* 



