Seiches in. Some Lakes of Japan. 



53 



and calculating T Avith Du Boys's formula in the following form, 



rp '2 /• dx 1 r dx 2 'r dx 



■y/ g / \^ g ^/ g / ■>/ h ■>/ g J ^Z h 



i _^ _l ^^ J+ I 



41 



V g 



we find that r= 16.21 minutes. 



Tabulating the results obtained before, we have 



TABLE 28. 



No. 



T. 





m 



1 



13.51 



2 



14.02 



3 



14.29 



4 



14.18 



5 



14.31 



Ô 



14.97 



7 



15.75 



8 



16.21 



This shows without any doubt that the observed period of 15.38 

 minutes must belong to the longitudinal uninodal seiche. When we 

 bear in mind the great variations both in the depth and in the 

 breadth of the lake, it is rather wonderful that the calculated periods 

 differ so little among themselves. We see from the above calcula- 

 tions that if we merely wish to determine which of the observed 

 periods belongs to the uninodal seiche we may use any of the 

 methods given above. Of the calculated periods the seventh value 

 comes nearest to the one observed, though the mode of calculation 

 is not theoretically correct. The last agrees best with the theoretical 



