24 K. HONDA, T. TERADA, Y. YOSHIDA, AND D. ISITANI. 



PI. Vir. Fig. 2-3. Tlie periods usually observable are 12.0", 

 21.3"- 22.0'", 23.0"- 27. G'" and 55.2". The periods observed in 

 the bay in the case of a storm or a sea wave of distant origin 

 are those usually found in the bay. The calculated period 24.0", 

 which corresponds to the seiches between Miyako and the end 

 of the bay, fairly accords with the conspicuous observed periods 

 21.3"-22.0". 



(3) Odsuchi (Aug. 11-12, 1902). Top. 17. 



Odsuchi is a bay not far from Miyako. Here the undulation 

 is conspicuous ; the period observed by Dr. Imamura is 27.0", 

 while the calculated period is 30.7." 



(4) Ryôishi and Kamaishi (July 21-28, 1004). Top. 18-19. 

 PI. Vll, Fig. 4 ; PI. Ylll, Fig. 1-2. 



The bays of Ryôishi and Kamaishi in Pikuchiu have 

 their mouth in common and in reality form a W- shaped bay. 



The principal station was chosen at Kamaislii at the end 

 of the latter bay ; other stations were Heida, Kamagasaki, Washi- 

 nosu and Aodashi. The simultaneous observations in these 

 stations taken three at a time showed that the phase of the 

 principal secondary undulation is the same for these stations. 

 The amplitude of the undulation did not much diminish at 

 Kamagasaki and Washinosu as compared with the amplitude at 

 Kamaishi. At Aodashi near the mouth of the bay, the second- 

 ar}^ undulation was very inconspicuous. The undulations at 

 Ryôishi were much complicated by the superposition of shorter 

 waves. We could sometimes find the undulations of the same 

 period and phase as those at Kamaishi. The periods observed 

 are 12.0"-13.2", 20.3" and 22.8" at Ryôishi, and 8.6"-9.4", 

 20.3" and 24.8"-26.0" at Kamaishi ; the calculated periods for 

 these bays are 21.3" or 20.0" and 24.8" or 22.3" respectively. 



