82 



s. Nakamura and K. Honda. 



and 21 6. Then evidently high and low waters in the lake are 

 represented by the points a and h respectively, (Fig. 22) and the 

 retardations for them are equal to each other, for the latter are 

 simply the distances between the ordinates at Aa and Bh. 



O^^aiv Mde^ — 







rjleam. ^ez^eB 











1 













.. 



Fig. 21 a. 



Fiff. 21 b. 



Fi^'. 22. 



But when the mean level of the lake is sinking, then after 

 high water a, as the relative velocity is diminished, the rate of the 



