30 



Art. 9.— T. Terada: 



maxi man frequencies fall decidedly in the night hours, mostly a 

 little before midnight, while at the same time, a secondary 

 maximum in the day time is suspected in some of the graphs. 



Y 



IDQ 



Fig. 8, Y. 



30'-50' 50'-7(3' 70'-90' qo'-l30' i30-200' 



HVVI 



mffln 



3Z1SI 



6 ,2 \3 i^ c 



Sa 



ö- 



AU 



V^ 



ft 



TÎ n~J4 e 



ij C4 s 12 li 24 



YEAR 



I 6 II IS i1 e 12 I« ^^ o 11 IS :+ 



im;^ 



^ 



II I! Z4 6 II '» -24 



30'- .200' 



Ö u I« 



The frequency of all waves, 30'-200', shows a maximum in 

 the morning and a minimum in the evening. 



It is to be remarked that the diurnal variation of the number 

 of ' ' spasms ' ' as well as ' ' pulsations ' ' studied by W. van 

 Bemmeln, and also that of the frequency of the disturbed hours, 

 as could be deduced from the diagrams in Bidlingmeier's paper 

 above cited, show a character quite similar to the variation of the 

 frequency of the "longer waves" here studied, up to the 

 appearance of the secondary daytime maxima. 



