DE VEL OP ME NT OF SEISMOL OG V IN JAPAN 303 



On the other hand, the radioactivity of mineral spring lias been 

 studied hy D. Isitani, H. Ikeuti, S. Ono, and othei-s/^^ The results are 

 compiled into a table in K. Ishizu's '^ The Mineral Springs of Japan," 

 Recently, Saem. Nakamura^-^ drew attention to the interesting fact 

 that the contents of the radioactive emanations show a systematic 

 excess in the springs along the Japan Sea side, as compared with 

 those on the Pacific side. 



The change of level of the underground water was investigated 

 by Seiji Nakamura and K. Honda^"^ and the effects of the barometric 

 and tidal pressures have been established. The disturbance of the 

 level before and after some earthquake was found to continue for 

 several hours. The sensitiveness of the geyser of Atami to the 

 variations of atmospheric pressure has also been established. On the 

 occasion of the recent great earthquake, abnormal changes in the 

 underground water level have been reported from many sides, though 

 unfortunately no record of instrumental measurement is at hand. 

 Eecently, K. Suda and K. Tanahasi*^''^ investigated the change of level 

 in an artesian well on the coast near Kobe and Osaka. They found 

 an approximate proportionality between the variations of the level of 

 the well and of the neighbouring sea, with a slight lagging of the 

 former after the latter. The influence of precipitation was also 

 examined. 



The investigations of the secondary undulations of tides in bays 

 and gulfs, in connexion with the studies on tsunami have already 

 been reviewed. The research into the seiches of lakes has also been 

 ftivoured by many investigators*^^) in this country, since Nagaoka 



(1) Isitani, T.S.B.K., 4 (1908), 370, 416; 6 (1912), 275; 7 (1913), 150, 221; 8 

 (1915), 15. D. Isilaai and K. Manabe, T.S.B.K., 5 (1910), 226; 6 (1912), 220, 291, 308. 

 D. Isitani and Yamakawa, T.S.B.K., 6 (1912), 178; 7 (1913), 10, 32. H. Ikeuti, T.S.B.K. 

 7 (1913), 176, 178; 7 (1914), 422, 424, 425. S. Ono, T.S.B.K., 7 (1914), 419. K. Fuji, 

 T.S.B.K., 8 (1915), 13. T. Okaya, N.S.B.K., [iii] 1 (1919), 351. M. Hayakawa and T. 

 Nakano, Mem. Kyo, 5 (1912-3), 137. 



(2) Sait6 Honkwai Gakuzyntu Kenkvu Hokoku, No. 1 (1925). 



(3) TS.B.K., 2 (1903), 65"; 2 (1904)," 123; Pub., 18 (1904). 



(4) U.t.S., 5 (1925), 223. 



(5) Seiji Nakamura and Y. Yoshida, T.S.BK., 1 (1902), 115. D. Isitani, T.S.B.K., 

 3 (1906\ 170. T. Terada, T.S.B.K., 3 (1906), 174. K. Honda, T.S.B.K., 3 (1906), 220. 

 Seiji Kakamura, T.S.B.K., 4 (1907), 73. K. Aichi, T.S.B.K., 4 (1908), 220. A. Tanaka 

 and Seiji Nakamura, T.S.B.K., 5 (1910), 394. Seiji Nakamura and K. Honda, Journ. 

 Coll. Sci. Tok., 28, Art. 3 (1911). Keizo Sano, T.S.B.K., 7 (1913), 24; J.M.S., 31 (1912), 

 446, e. ; 32 (1913\ 37, e. Honda and Matsushita, Sci. Rep. Toh., [i] 2 (1913). 131. 

 Second Year Students of Physics, Tohoku Imp. Univ., T.S.B.K., 7 (1913), 24; Sci. Rep. 

 Toh., [i] 1 (1911-12), 243; 2 (1913), 163. T. Okada, S. Fujiwhara and S. Maeda, 

 T.S.B.K., 7 (1914), 210. K. Honda, Sci. Rep. Toh., [i] 4 (1915), 323. Excursion 

 Parties of Tohoku Imp. Univ., Sci. Rep. Toh., [i] 6 (1917), 31 ; 7 (1918), 197. K. 

 Aichi, T.S.B.K., 9 (1918), 464, 478. Saem. Nakamura, N.S.B.K., [iii] 2 (1920), 82. 



