184 F. OMORI AND K. HIRATA : 



Tlie preliminary tremor, whose duration was 3.6 seconds, con- 

 sisted of very fine ripples of an average period of 0.05 second. 



The principal portion, whose duration was 3.6 seconds, 

 consisted of movements of the maximum 2a of 1.0 mm. in the 

 (EW), and 1.2 mm. in the (NS), the amplitude of motion being 

 nearly equal in the two horizontal components. 



In the end portion, the motion consisted of ripples super- 

 posed on slight slow undulations. 



30. Eqke. No. 22. The 26th December, 1897 ; 3 p. m. 

 Intensity, slight. The date is possibly erroneous, there being 

 in the Central Meteorological Observatory no report relating to 

 this earthquake, which was evidently a rather great shock at 

 a distance. 



The duration was about 150 seconds. 



The preliminary tremor, whose duration was 26 seconds, 

 began very gradually and consisted of small slow undulations 

 perfectly free from superposed ripples. 



The principal portion consisted of slow undulations of an 

 average period of 2.2 seconds, the motion being almost entirely 

 in the (EW). The maximum motion was 2a=0.6mm., T=2.3 

 seconds. 



The average period of the ripples superposed on the slow 

 undulations in the principal portion was 0.11 second, the maxi- 

 mum 2a being 0.2 mm. 



31. Eqke. No. 23. The 31st December, 1897; 11.50.28 

 p. m. Intensity, sliykt. The origin was situated to the ESE of 

 Miyako. The duration was 70 seconds. 



The motion, which consisted entirely of slow undulations 

 free from superposed ripples, was about twice as great in the 

 (EW) as in the (NS), V.M. being almost zero. 



