Semarang"; 



Direct comparison of the Batavia-Semarang current to the magnetic 

 component furnished: (June 18 — 21, '07): 



The last two values fit in very well with the scheme of the values 

 founrl for the Cheribon-current, but the first three show a much 

 quicker increase when the dui-ation of the vibration is shorter. 



This peculiar increase immediately strikes one when regarding the 

 registered lines. In order to investigate whether that increase of the 

 influence of the duration was connected with the increase of the 

 distance of the two stations between which the earth-current was 

 measured, 1 asked for and obtained direct connection with Makassar. 

 The loss by defective isolation on the line however was so great, 

 that the real distance had not obtained any lengthening of importance. 



On the trustworthiness of the results. 



A certain doubt has always been left when observing earth-currents 

 whether the results arrived at do give an idea of the real existing 

 earth-current. 



According to Schuster (Terr. Magn. Ill, p. 130) the intensity of 

 the current is really to be determined by switching on in the circuit 

 a cell of known E. M. F. I have therefore always used this 



