T. Terada 23 



We have already shown that when a centre hes far in the Japan 

 Sea, the entire Pacific coast stands under nearly equal conditions, 

 as far as the effect of the position of the coast line relative to the 

 centre is concerned. Hence the influence of these depressions re- 

 mains persistent when we proceed along the different districts. 

 For the Pacific depressions, the case is quite different ; the isohyets 

 cross the land more or less transversally, the expectation var^dng 

 rapidly along the coast line. In other words, the part of the centre 

 loci on the Pacific side moves with the centre, while on the Japan 

 Sea side, it remains comparatively stationary. 



General Theoretical Considerations. 



Though we are afraid that we may he drawing our inference 

 rather too far on the basis of too scanty materials, it will not be 

 quite out of place to attempt here a discussion on the general theo- 

 retical aspect of tlie problem at hand. 



Among the numerous factors determining the unsymmetrical 

 distribution of precipitation due to a cyclone, we may conveniently 

 distinguish the following three as the most essential : 



(1) The first maj^ be called '' thermal and planetary " for the 

 sake of simplicity. It consists in the difference of temperature witli 

 the latitude and may be considered always present regardless of the 

 distribution of land and water. This influence would predominate 

 if the earth were completely covered with ocean or land only, and 

 would bring, according to the usual simple theory, more abundant 

 rain on the eastern side of a depression. 



('2) The second may convenient!}^ be called "thermal and 

 geographical" and consists in tiie difference of tliermal condi- 

 tions governed by the distribution of land and water, especially of 

 continents and oceans. If this influence predominates, we may 

 expect in the northern hemisphere the following : In summer 

 when the land is generally warmer than tlie water, the area with 

 the heaviest precipitation will lie in that direction whicli, viewed 

 from tlie centre, has the land on tlie right side, provided of course 

 that the land is sufficiently humid and the air kept nearly in 

 saturation. But if the land be very arid, the reverse may occur, if 



