On Sea-Waves connected ivith a Japanese Earthquake. 579 



lines per sq. cm. per ampere. By opening K a throw was 

 obtained first with the needle exactly in the coil plane (normal 

 throw), next with the needle turned out of the coil plane by 

 a small angle 6* (abnormal throw). The difference between 

 these throws expressed as a percentage of the normal throw 

 and plotted against the current I flowing round KLB at 

 the moment of break gave one of the points of fig. 2 ; and the 

 other points corresponding to other values of 6 and of I were 

 obtained in like manner. 



On examination it is seen that the whole of these results 

 can be gathered up into the formula 



Percentage excess of Abnormal! OOA/)T , ,.,, 



over Normal throw |= 33001, . . (4 6) 



where 6 is in degrees and I in amperes, 6 being regarded as 

 positive when the initial displacement of the needle is in 

 the same direction as the throw, but negative when in the 

 opposite direction. 



From a comparison of (4 b) with (4 a) it is to be inferred 

 that the induction-coefficient of the needle of the particular 

 galvanometer used was "0015, a value not very different 

 from that previously adopted for a. 

 Owens College, Manchester, 



LVI. On the Sea-Waves connected with the Japanese Earth- 

 quake of June 15, 1896. By Charles Davison, Sc.D. 

 F.G.S.f 



[Plate V.] 



THE Japanese earthquake of June 15, 1896, is one that 

 deserves to have its history fully written. So far, it 

 has only been briefly referred to in a few papers J, with the 



* In reality it was the galvanometer-coil that was turned, the needle 

 being left in a fixed plane and under a fixed controlling held ; but it is 

 more convenient to speak, as above, of the displacement of the needle 

 relatively to the coil thought of as fixed. 



r Communicated by the Author. 



| J . Milne, " The Great Sea-Waves in Japan." Geogr. Journ. vol. viii. 

 (1896,, pp. 157-160. 



J. Milne, [" On the Sea- Waves and Earthquakes of June 15, 1896, in 

 North Japan "]. Brit. Assoc. Report (1897), pp. 25-81. 



F. Omori and K. Hirata, " Earthquake Measuremeut at Miyako." 

 Journ. Sci. Coll., Imp. Univ., Tokyo, vol. xi. (1899), pp. 161-195, 

 especially pp. 164-166, and tigs. 1 and 8. 



"The Great Seismic Wave in Japan." 'Nature,' vol. liv. (1896), 

 pp. 449-450. 



" The Great Disaster in Japan, June 15th, 1896." (A series of articles 

 reprinted from the Japanese Gazette, Yokohama.) 



