40 K. HONDA, T. TERADA, Y. YOSHIDA AND D. ISITANl. 



resolved into three components shown in PI. XXXTI, Fig. 1, 2. 

 The principal semidinrnal components at Ivamcura and Ogenra 

 have nearly opposite pliases to each otiier. It is to be observed 

 that in these fignres, the dinrnal components were not separat- 

 ed ; they are very conspicnons at Kamcura and Ogenra, bnt 

 not at Hinonra and Shioyasnmi. 



When the current was rnshing from tlie Pacific into Ilarima- 

 nada an interesting phenomenon was observed. As the current 

 increased its velocity, a regular undulation of about 2.5'" (PI. 

 XX VII I, Fig. 4) became gradually conspicuous and attained a 

 maximum amplitude of about 18 cm., and tlien gradually de- 

 creased with the diminishing velocity of the current. In the 

 records of Shioyasnmi (PI. XXVIII, Fig. 1-3), thickly zigzaged 

 portions indicate the existence of such waves. Thus it seems 

 very probable that the current behaves like a jet of air blown 

 into the mouth of an organ pipe, causing standing oscillation 

 of the air column in the pipe. Tlie torrent of watei' rushing 

 from tlie Pacific into the strait excites a standing oscillation 

 of the water in tlie neighbourhood of tlie Strait, A few years 

 ago. Professor H. Nagaoka expressed the possibility that the 

 KurosJiiwo, which is the current along the coast of Japan with 

 a velocity of a few knots per hour, may be the origin of the 

 long waves observable on our coasts. The present case affords 

 a good example for ilUistrating the above view on a small 

 scale. 



If we bring two records of consecutive days of normal 

 weather into coincidence as regard the tidal phase, we observe 

 in each record, the same succession of the secondary undula- 

 tions following one after another ; this remarkable fact is also 

 noticeable on some other coasts. 



