298 T. Teeada and T. Matuzawa 



Though the duration of the observation was not very long, the results 

 seem to show some effect of the tidal loading, among others. 



Connected with these subjects, we cannot pass on without making 

 allusion once more to the service rendered hj the Military Land 

 Survey and the Naval Hydrographic Office in revealing the remarkable 

 change in the earth crust connected with the great earthquake. If the 

 investigation of the most minute variations of the level at a selected 

 number of stations, is important, it will be at least equally desirable 

 to keep watch of the gradual movement of the crust over an extensive 

 area, not only of the land but also of the submarine bed of the 

 neighbouring seas. We may be allowed, therefore, to take this 

 opportuiiity for expressing our hope that our Military and Naval 

 authorities would graciously continue of their most useful and efficient 

 participation in our peaceful warfare against the most dreadful natural 

 calamities. 



For the studies regarding the deformation of the earth crust, the 

 mareographic data are of no small importance. Fortunately, continu- 

 ous records for thirty years have now been gathered by the Military 

 Land Survey for a number of stations^^' distributed over the entire 

 coast. These data have already been occasionally utilized by Omori*^-^ 

 in his research on the relation between earthquake frequency and 

 sea-level, especially with respect, to the seasonal variations. In the 

 latter respect, Nagaoka^^^ discussed the effects of the temperature 

 variation of water on the sea-level and alluded to its possible relation 

 to the annual term of the variation of latitude. 



The secular variation of sea-level has also been cited and discussed 

 with reference to the cause of earthquakes. Even a kind of prediction 

 of earthquakes based on tlie crude observations of daily levels has 

 been s})oken of in some quarters. In this respect, the recent work by 

 N. Kawakami*^**^ is noteworthy. Following an investigati(m by K. Taguti, 

 he analysed the slow variation of the sea-level into a secular term 

 proportional to tiuie and the conspicuous 19-year tide depending on 

 the moon's ascending node, with respect to the chief mareographic 

 stations. After evaluating the correlation coefficients with respects to 



(1) A great majority of the stations have recently been transferred to the 

 supervision of the Imperial Marine Observatory, Kobe. 



(2) T.S.B.K., 2 (1904), ICO; 2 (1905), 297, 321. 



(3) T.S.B.K., 4 (190S), 382. 



(4) Mem. Imp. Mar. Obs., 2 (1925), 71. 



