DISTRIBUTION OF EARTHQUAKES IN TIME. 241 



for Japan, we see that a great increase in the number 

 of earthquakes, as we come towards the present time, is 

 not so observable as it is in the other columns. 



The explanation for this probably lies in the fact that 

 Japan has practised civilised arts for a longer period than 

 many of the European and other countries mentioned in 

 the table. 



In Japan, no doubt, the records of later years have 

 been more perfect than they were in early times, but this, 

 although so potent an effacer of what was probably the 

 true state of natural phenomena in the case of Europe, 

 has not quite obliterated the truth in Japan ; for instead 

 of an apparent increase of seismic energy since early times 

 it shows a slight decrease. 



To draw up a table of earthquakes such as the one 

 which has just been given, and then, after the inspection 

 of it, draw conclusions as to whether there has been an 

 increase or decrease in seismic energy, is, however, hardly 

 a just method of reasoning. The earthquakes, taken as 

 they are, for the whole of Japan, represent a collection 

 of places some of which are 1,000 miles apart. When we 

 consider that many earthquakes which occurred at one 

 end of this line were never felt at the other end, in order 

 to justly estimate the periodicity of seismic phenomena 

 it would seem that we ought either to take some par- 

 ticular seismic area or else the whole world. 



The particular area which has been taken is that of 

 Kioto in Central Japan, and the earthquakes which have 

 been felt there are enumerated in the table. 



In order to show the variation in seismic activity 

 of this district a curve has been plotted, fig. 35, 

 with ordinates equal to the values given for the Kioto 

 earthquakes during succeeding centuries. The upper 

 points of these ascending and descending lines are 



