SECOND.\EY UNDULATIONS OF OCEANIC TIDES. 



109 



become so long as 8'', unless the mean depth of the Port be 

 less than one meter. This period is probably due to the un- 

 dulation of the whole basin with its narrow neck communicating 

 with open sea. For the calculation of the period corresponding 

 to tliis mode, the necessary data were estimated from the chart 

 given in Harris' Report: >S:=13.7 x 10' m'., /=2.95km., 5 = 4.08 

 km., 7^:== 18.4 m. and ;.= 200km. The period calculated from 

 these data is 8.39" which almost coincides with the observed 

 period. 



Beside the above enumerated examples, there are many 

 bays or straits, the forms of which seem favourable for their 

 own standing oscillation of long periods, and in which the 

 ranges of tides are comparatively large. The periods of these 

 oscillations w^ere estimated as follows : — 



In conclusion, we wish to express our best thanks to Prof. 

 H. Nagaoka under whose supervision the entire work has been 

 carried out and who gave us much useful instruction throughout 

 the course of our investigations. Equal thanks are due to Prof. 



