180 F. OMORI AND K. HIKATA : 



In the end portion, the average period of ripples was 0.10 

 second in each horizontal component. 



The ripples were superposed on slow undulations of an 

 average period of 1.7 seconds in the (EW), 1.0 second in the 

 (NS), and 0.8 second in the (V). 



22. Eqke. No. 1&. The date is not given, but the record 

 was taken on the same smoked paper as Eqke. IS^o. 16. In- 

 tensity, very slighl. The duration was 23 seconds, there being 

 no V.M. The shock consisted of very fine ripples, which were 

 greater in the (EjV^) than in the (NS). There was no pre- 

 liminary tremor, and the motion was greatest at the commen- 

 cement, thence gradually diminishing. The average period was 

 0.082 second in the (EW), and 0.084 second in the (NS). 



23. Eqke. No. l<d^^. The date is not given, but the record 

 was taken on the same smoked paper as Eqke. No. 16. In- 

 tensity, very slight. The duration was 8.5 seconds, there being 

 no V.M. The average period was 0.09 second in the (EW). 



24. Eqke. No. 17. The 27th August, 1897; 1.6.31 a.m. 

 Intensity, slight. The origin was situated probably at 160 km. 

 SE of Miyako, and the motion consisted of slow undulations, 

 which were perfectly free from superposed ripples, evidently 

 indicating a very distant origin. 



The duration of the H.M. was 70 seconds, and that of the 

 V.M., 39 seconds. 



The preliminary tremor, whose duration was 21 seconds, 

 was succeeded by the maximum motion of the following elements: 

 (H.M.) 2« = 1.0 mm., T = 1.2 secoml, direction N 60° W. 

 (V.M.) 2a =0.1 mm. 

 The average period was 1.6 seconds in the (EW), and 0.8 

 second in the (NS). 



