Seiclies in Some Lakes of Japan. 



81 



Thus a given phase arrives at Washizu and Osaki simultaneously,. 

 and at Horie about 5 min. later. This accords well with the fact, 

 that the amplitude of the tide at Horie is smaller than at the other 

 places. 



The retardation of the tide within the lake is given in the next 

 table, in which the mean value of the times of high and low water 

 within the lake is compared with that of the open sea as calculated 

 before. 



TABLE 38. 



L 



^^^^^^^H 



H Sea. 



Eetardation. 



h 



Aug. 24 18 



m 



13 



Il m 



14 11 



h in 



4 2 



H 



23 



18 



20 7 



3 11 



L 



25 7 



42 



2 59 



4 43 



H 



12 



12 



9 3 



3 9 



L 



18 



35 



14 35 



4 



H 







21 1 

 3 51 





L 



26 8 



48 



4 57 



Thus the retardatian for a high tide is remarkably smaller than that 

 for a low tide, the mean value for the former being 3 hours and 10 

 min., while that for the latter, 4 hours and 25 min.. This 

 dissymmetry in the retardation may be easily accounted for by the 

 general sinking of the level of the lake, before alluded to. Let us 

 assume that the mean levels of the lake and the sea remain constant 

 and that the amplitude of the tide is also constant, so that the 

 changes of the levels can be represented by simple sinuous curves. 

 Further assume that the connection between the lake and the sea 

 is such that it can be diagrammatically represented by Figs. 2U 



