EARTHQUAKE MEASUREMENT AT MIYAKO. 195 



due to its having been obtained, not from the principal portion, 

 but from the preliminary tremor of the earthquake. Omitting 

 this case, we obtain for the focal-depths of the two earthquakes 

 Nos. 8 and 11, respectively the values of 15 and 9 km. 



December, 1898. 



Seism ological Institute, 



Tokyo Imperial University. 



