( 523 ) 



must not expect that that formula will give the real formula, as it 

 must be very complicated on account of the nature of the pheno- 

 menon . 



What according to me is clear from the diagram is that the 

 ratio of amplitudes for the vibrations of shorter duration will 

 gradually pass into those of longer duration (the six terms of the 

 daily variation) and so that between these two phenomena there is 

 also a gradual transition. 



The results for the earth-current Buitenzorg-Batavia and Billiton- 

 Batavia are again uncertain on account of the lack of agreement 

 with the magnetic component. I found : 



Buitenzorg-Batavia. 



Billiton — Batavia. 

 63 



74 

 66 

 58 

 41 



14 

 14 

 14 

 23 

 5 

 70 



If indeed these figures are trustworthy then the ratio of amplitudes 

 of the earth-current with respect to the magnetic component decreases 

 here too when the duration increases. 



The increase at the outset with very small duration is also found 

 in the above figures, even in much greater ratio than for the 

 Anjer- and Cheribon-current, 



The numbers for Buitenzorg are a little smaller and for Billiton 

 smaller than for Anjer, but still larger than for the Cheribon-current. 



The line to Poerwakarta I had but for two nights at my disposal. 



