On the Effect of Topography on the Precipitation in Japan. 23 



tion of the entire Pacific regions, i.e. (II4-IV + VI)/3,'^ which is 

 given in the third hne of the Table. The Japan Sea side, 

 (I + III + V)/3 shows nearly similar yearly variation as the Pacific, 

 except m a few years. 



Since the intimate relation of the earthquake frequency and 

 the barometric gradient has been already fully established by the 

 investigations^^ of one of the authors and also of K. Hasegawa and 

 Saemontaro Nakamura, it was suspected that it may be also the 

 barometric gradient that directly determines the rainfall on the one 

 hand and the earthquake on the other hand. Hence the earth- 

 quake frequency was compared with the different components of 

 the gradient prevailing in different parts of the land. After a 

 series of trials, it was found that the difïerence of the barometric 

 pressure, the Japan Sea stations minus the inland stations, shows a 

 parallel course with the earthquake frequency. Taking for the 

 inland stations Matumoto, Takayama, Hikone and Osaka, and for 

 the Japan Sea coastal stations Niigata, and Sakai, the difference is 

 given in the second line of the Table. XL 



Comparing this wdth the earthquake frequency (Fig. 5), it will 

 be seen that the earthquake curve shifted about one year earlier, 

 shows a rather remarkable parallelism with the gradient curve. 

 Whether the very curious correlation is merly accidental or not, 

 cannot be ascertained at present from such a scanty materiah 

 Though the apparent relation may appear rather absurd, the 

 possibility of such a coincidence cannot be excluded by a superfical 

 consideration, if we consider for an instance that the precipitation 

 of the last year may affect the barometric pressure of the year 

 concerned. 



A further investigation in this line is now in progress and we 

 hope will be able to clear up the apparent mystery in a near future. 



1) Here the values of (anomaly)/(mean anomaly) was averaged for the three regions. 



2) T. Terada, Proc. Tokyo Math.-Phys. Soc, vol. IV (1908) p. 454 ; K. Hasegawa, ibid. 

 Vol. VII (1913), p. 181 ; S. Xakaumra. Ihil. Vol. VIII (1915), p. 69. 



