EAE,THQUAKE MEASUREMENTS OF RECENT YEARS. 67 



equally in all directions. Moue than 120 complete waves whose 

 periods varied from 0*7 seconds to 3 seconds were registered. Not- 

 withstandingf the existence of the considerable horizontal motion no 

 vertical motion appeared. 



No. 4. — This was one of the local shocks which frequently 

 occnr in this and in other parts of the country. Its area of disturb- 

 ance is often not more than a few square miles. The motion is 

 genernlly feeble in those local shocks. 



No. 5. — The ratio of the vertical motion to the horizontal 

 motion was 1 to 10 in amplitude and 1 to 13 in duration. 



No. 13. — More than 50 distinct waves of small amplitudes were 

 counted. 



No. 14. — This extensive earthquake originated among the moun- 

 tain di.^trict of Shinano which is one of the highest portions of the 

 country 2,000 ft. above the sea level. There are one active and many 

 extinct volcanoes. The seismic waves were not propagated much 

 beyond Tokyo. 



No. 21. — Tokyo was in the middle of the shaken district. 



No. 23. — Both horizontal and vertical tremors were visible from 

 tlie beginning ; but at the fifrh second tliere suddenly appeared a 

 large horizontal motion (maximum). Distinct vertical waves came 

 a few se("onds later. See Plate XT, Vol. I of this Journal. 



No. 25. — 'The motion commenced slowly and was not preceded 

 by Cjuick tremors as is usually the case. The Observatory was com- 

 parativelv near the orio-in of the disturbance. 



No. 33. — This was a middle sized earthcpiake in which the 

 observing station was near its origin. The maximum horizontal 



