Seiches in Some Lakes of Japan. 89 



different speeds of the recording cylinder. Here the motion was 

 so regular and the period so constant that the phase of the seiche 

 after twelve hours could be predicted. The period found in this 

 case was 



T = 7.70 minutes. 

 In the following year we had an opportunity to make further 

 observations on the seiches of this lake. On the 6th of July 1906, 

 alimnimeter of the " H " type was placed at Senju at the western 

 end of the lake and another at Shöbugahama situated near the 

 middle of the northern shore. From simultaneous records (Fig. 27), 

 it was found that the period of the seiche was 7.7 minutes as in the 

 previous year, and that the phases were the same at the two 

 stations, and as the amplitude was very much smaller at Shöbuga- 

 hama than at Senju, we saw that the nodal line must pass a little 

 east of the former station. On the next day, simultaneous records 

 were taken at Senju and Utagahama at the eastern end of the lake, 

 and, as was expected, it was found that they were in the opposite 

 phases. Leaving the limnimeter at Senju in its place till the end 

 of the observations, the other instrument was carried to Shinnagi 

 on the northern shore, where it recorded a motion of much smaller 

 amplitude but of the same phase as that of Utagahama. As the 

 oscillation was very regular, the phase of the motion at Shinnagi 

 ■could be predicted from that at Utagahama. These two places are 

 therefore on the same side of the nodal line. On the 8th, the 

 motion of the water at Furunagi was examined with the result 

 that the limnogram was a straight line showing that the nodal line 

 passed through this spot. Simultaneous observations at Asega- 

 hama and Chûzenji on both sides of the lake near its eastern end 

 also indicated that the oscillations of the water were in the same 

 phase at these places. 



