362 s. SEKIYA 



flatter appearance. In Fig. 3, however, several vertical outbursts of 

 considerable amplitude are observed, with inert intervals between. 

 They practically subside beyond the seventy-first second and the 

 disturbances are then entirely confined to the horizontal plane where 

 they ontinue with great force for more than one minute. Dis- 

 appearance of the vertical motion long before the horizontal is the 

 usual phenomenon. Also when large vertical motion occurs there 

 is usually to be found simultaneous large horizontal displacement, 

 but the latter often may be recorded without the former. 



