60 



K. HONDA, T. TERADA, Y. YOSHIDA, AND D. ISITAN]. 



constant for different depths. Vertical planes, which are parallel 

 to wave ridges and fixed relative to water, make a to and 

 fro motion similar to the case of aerial vibration. The nodes of 

 aerial stationary waves correspond to the loop of the water 

 wave and vice versa.'^' If we nse the analogy for the expression 

 of the kinetic energy, wo have 



1/8 7rb\. 1 f'S 7th 



7ih\ 



This relation seems to be sufficient for the estimation of the 

 order of magnitude of the mouth correction. It is to be remarked 

 that if we assume 



] «t sin __— cos 



% 



T 



the result is not altered. 



In the following table, the mouth corrections are given in 



terms of the ratio of the breadth to the length of the bay : — 



Here it is to be remarked that the 

 applicability of the above formula 

 becomes less, when the ratio of the 

 breadth to the length becomes 

 greater than unity, since in such 

 a bay, the nonuniformity of hori- 

 zontal displacement for each 

 transverse section becomes too 

 great. 



{h) Irregularly shaped bay. 



The problem of finding the period of oscillation in an irreg- 



*) See Lamb, Hydrodynamics. 3rd Ed. § 188. 



