84 



S. Nakamura and K. Honda. 



^oa>- -u/nteAy 



^o-ti^/tic/c- 



Fig. 21 a. Fig. 24 b. 



During a portion of low tide the head of the water flowing 

 outward is determined by the height of the level of the lake above- 

 the bed of the channel, and not as in the previous case b}^ the- 

 difference of their levels. The rate of the falling of the water in 

 the lake is decreased, and causes a similar dissymmetry in the 

 retardations of high and low waters. The efïect of the inconst<incy 

 of the cross section of the flowing water probably makes this more- 

 prominent. 



