SECONDARY UNDULATIONS OP OCEANIC TIDES. 27 



specially fitted for the comparison of the phases of the second- 

 ary undulations at diflerent stations along the bay. Stations 

 were Ofunato, Sunagosaki, Takonoura and Hosoura. The 

 simultaneous observations between Ofunato and other stations 

 were taken at three different dates. 



Fig. 1 and 3, or 2 and 4 are the records of the simultane- 

 ous observations ; 1 and 1', 2 and 2', and 3 and 3' in these curves 

 indicate the positions of tlie corresponding time. They clearly 

 show that the phase of the conspicuous undulation is the same 

 for these three stations. 



The periods observed are 5,5"\ 12.8'"-16.8"\ 36.0"-39.1"^ 

 and 41.5"-43.5"\ while the calculated period is 36.4'" in good 



A 



agreement with the observed. At Ofunato and Hosoura where 

 undulation of periods 12.8'"-16.8'" was sometimes observed, the 

 phases of the undulation are opposite to each other. The 

 undulation was very inconspicuous at Sunagosaki situated mid- 



A 



way between Ofunato and Hosoura so that it may probably 

 be a binodal oscillation of the bay. 



Waves of the short period 5.5™ appeared at Hosoura and 



A 



Sunagosaki but not at Takonoura and Ofunato ; the absence of 

 the waves at the latter stations is possibly due to the effect 

 of shadow. 



(9) Niiyama (July 21-Aug. 3, 1903). Top. 25. PL XI, 

 Fig. 1-2. 



Niiyama is small V-shaped bay ; the undulation is not 

 very conspicuous. The observed periods are 6.4" -7.6'", 11.0"- 

 12.8'", 20.0"'-23.7"', 27.5'"-30.7"\ 61.5"\ 71.G"' and 90.0'"; while 

 the calculated period is 7.5'". 



(10) Ayukawa (July 18-21, 1903). Top. 26. PI. XI, Fig. 

 3 ; PI. Xn, Fig. 1-2. 



