84 REPORT — 1S95. 



Remarlis. 



Shock l,3ul. — Commenced ver}- gentlj' for about 36 seconds, when a violent shaking, 

 lasting 16 second;-", took place. It then died out. 



Shock 1,352. — Tliis comraenced gently for 32 seconds, after which, for 9 seconds, the 

 motion was strong. Then it died out. 



Shock 1,366. — Strong motion, lasting 15 seconds, commenced after 9 seconds of pre- 

 liminary motion. 



Shock 1,368. — Was very slow and gentle. After one minute the horizontal motion 

 was marked for about 13 seconds. During 26 seconds it showed 

 nineteen large waves. 



Shock 1,37G. — At first this was slow, but became stronger after 3 minutes 12 seconds, 

 when for the next 30 seconds it was pronounced. 



IT. Observations with Horizontal Pendulums. 



In the years 1883, 1884, 1885, 1887, 1888, 1892, and 1893 I embodied 

 in Reports to the Association some account of work which had been 

 carried out in Japan in the investigation of earth tremors or pulsations 

 and earth tilting. The Twelfth Report (1892) describes a pair of exti'emely 

 light horizontal pendulums the movements of which were recorded on 

 photographic plates or films, and gives some account of the analysis of 

 the resulting records. The observations were continued during the 

 following year, and, as stated in the Thirteenth R,eport (1893), it was 

 observed that the direction of earth-tilting movement and also of earth- 

 quake movement in the majority of cases coincided with the direction in 

 which strata have been folded to form mountain ranges bordering the 

 Tokio plain. Anotlier observation was that certain earthquakes had been 

 preceded by an abnormal amount of tilting. 



In consequence of the liberality of the Royal Society of London dur- 

 ing the last year I have been enabled to extend these observations, usin^ 

 six horizontal pendulums, each provided with photographic recording 

 apparatus. 



The places of observation have been in Tokio, at my house, on a massive 

 stone column, and at a place about 1,000 feet distant in an underground 

 chamber on a concrete bed ; at Kanagawa, in an artificial cave driven in a 

 soft tuff rock at a depth of 50 feet below its junction with 50 feet of over- 

 lying alluvium ; at Yokohama, in a cave driven at the junction of the tuff 

 and alluvium ; and at Kamakura, in a cave in the tuff which at this j^lace 

 is hard and dips at an angle of 30" X.E. All these places lie from Tokio 

 on a S.S.E. line, and are respectively 20, 23, and 38 miles distant from my 

 house. At Kanagawa and at my house there is only one instrument, and 

 the booms of these pendulums point N.W. At the other stations two 

 instruments have been or are now being used, and these are placed at 

 right angles to each other, one pointing N.W., or parallel to the strike of 

 the rocks, and the other N.E., or parallel to the dip. At Kamakura 

 observations were made for two and a half months, when the instruments 

 were brought to Yokohama. At this latter place, owing to a series of 

 accidents, one of which was the collapse of the roof of the cave, up to the 

 present the observations have been extremely few. At Kanagawa, 

 although the cave is wet, the observations have been fairly continuous. 

 In Tokio, where I am able to see the instruments every day, but few inter- 

 ruptions have occurred. The chief part of this report, therefore, refers te 

 Kamakura and Tokio. 



