4 Art. 6.— T. Terada : 



by choosing suitable scales of the coordinates such that the ranges 

 of variation on the diagrams were nearly equal for the two dia- 

 grams. This was approximately effected by taking the areas of fa- 

 culté as equivalent to twice the areas of the spots. On the spots-facu- 

 lœ-diagram thus obtained, the lines of demarcation were drawn se- 

 parating the areas with O and x respectively. Though the results 

 are not quite simple, we may classify the different stations into the 

 following three classes, according to the distribution of the years 

 of maxima and minima, or the situation of the lines of demarca- 

 tion upon the diagram: 



Class I. Frequency is minimum when |iV,— Ä| or \Nf—Sf\, 

 or briefly UV— xS'I is small. The stations belonging to this class are 

 Tainan*'^ Taityû*, Naha, Kagosima, Nagasaki, Kumamoto, Huku- 

 oka, Matuyama, Koti, Tadotu, Tokusima, Wakayama, Hirosima, 

 Hamada, Okayama, Hikone, Nagoya, Hukui, Kanazawa, Yagi*, 

 Matumoto, Nagano, Kôhu, Utunomiya, Maebasi, Kumagae, Tyosi, 

 Mito, Mera*, Hukusima, Kanayama, Miyako, Yamagata, Aomo- 

 ri, Hakodate and Nemuro*. 



Pier. 1. Hirosima. 



Fig. 2. Simonoseki. 



1) The stations marked with * are those for which the ' felt ' earthquakes only were 

 taken. 



