212 



REPORT — 1887. 



Seventh Report of the Committee, consisting of Mr. R. Etheeidge, 

 Mr. Thomas GtRay, and Professor John Milne (Secretary), 

 appointed for the purpose of investigating the Volcanic Phe- 

 nomena of Japan. {Draivn up by the Secretary, 1887.) 



The Gray-Milne Seismograph. 



The seismograph, wliich in 1883 was constructed partially at the expense 

 of the British Association, still continues to give satisfactory results at the 

 Imperial Meteorological Observatory in Tokio, where it is installed as the 

 reference instrument. 



In the following table its i-ecords, as published in the daily papers and 

 the official reports, are given for the last year. The time is noted for a 

 particular wave in a disturbance. The period or time taken to describe 

 one of the principal vibrations is given in seconds. 



The numbers in the amplitude column give the total range of motion, 

 or the double amplitude, in millimetres. 



Catalogue of Earthqualws recorded at the 3Ieteorologioal Observatory, Toldo, letween 

 May 1886 and May 1887, by the Gray-Milne Seismograph. 



