Seiches in Some Lakes of Japan. 



27 



29.4x14 



16.1 X 7 



25.7 X 27 



15.9 X 9 



25.-5 X 12 



13.9 X 9 



25.8x31 



12.6x10 



25.2 X 46 



12.3 X 5 



25.0 X 39 



11.6 X 9 



24.9 X 6 



10.8x14 



22.8 X 6 



10.0 x 15 



22.5x14 



9.9x19 



22.8 X 17 



8.7 X 5 



During this series, we had a heavy storm wliich threw tlie lake 

 into a violent motion with an amplitude of about 10 cm., which is 

 about five times larger than its usual value. Tlie period at that 

 time was 16.5 minutes. 



Plotting the number of observed waves as ordinates and the 

 corresponding periods as abscissae on a section paper, we deduce 

 as the most probable seiches at Hikone the following five motions 

 Avith periods of 30.3, 25.3, 22.2, 16.5, and 10.3 minutes respective- 

 ly. For some of the limnograms at this place, see PI. V Figs. 1, 

 and 2. 



Imazu. 



Here Ave made three series of observations. During the first 

 series extending from the 30th. of July to the 7th. of August, we 

 studied and compared our instruments. The second series Avas 

 continued from the 14th. to the 23rd. of August, and the third series 

 from the 6th. to the 12th. of September. The different motions 

 then observed are tabulated below. 



