Yearly Variations of Terrestrial Phenomena and Solar Activities. Q 



In the following, the 'total' number of the shocks was gener- 

 ally taken, except for a few stations for which the 'felt' ones 

 were only available. In the former case, the number shows dis- 

 continuous increase at the introduction of the instrument as already 

 mentioned. This will, however, scarcely affect the general results 

 here concerned, even if we count a false minimum on this account. 



After determining the years of maxima and minima for each 

 station, the next procedure was to see if these years were associat- 

 ed with some peculiarities in the distribution of the solar activities 

 upon the two hemispheres. For this purpose, it was considered 

 most suitable to construct a diagram in which the abscissae x and 

 the ordinates y gave the areas of spot on the northern and the 

 southern hemispheres respectively, JV, and /Sfs say. Each year is 

 then represented by a point on the diagram with the coordinates 

 x = ]V„ y=Ss. Call this, for simplicity's sake, i\\Q spots-diagram to 

 distinguish it from a similar one in which the area of faculse on the 

 two hemispheres, Nf and Sf say, stand for x and y respectively, i.e. 

 the faculœ-dia,gram. Taking a given station, the points for the 

 years corresponding to the maxima and the minima of the seismic 

 frequency are marked with suitable signs, say O and x respectively. 

 If there exists any systematic relation between the distribution of 

 the solar activities and the earthquake, we may expect that the 

 points with the same mark would be arranged in a definite portion 

 or portions of the area of this diagram. On carrying out the 

 plotting, it was found that such is actually the case. For a great 

 number of stations the 3^ears with minimum frequencies are 

 crowded in a narrow zone lying along the both sides of the straight 

 line x=y, bisecting the angle between the axes of coordinates, 

 while the years of maxima are arranged on both sides of the zone. 

 For some other stations, the contrary was the case, the years of 

 maxima being distributed near the line x=y. 



Since the number of years taken was not great, the points of 

 maxima and minima on the diagram were often too sparsely distrib- 

 uted to enable us to draw the line of demarcation separating the 

 areas of maxima and minima. Hence, it was considered con- 

 venient to superpose the spot-diagram upon the faculœ-diagram, 



