1118 
MR. C. DAVISON ON THE ANNUAL 
Period. 
Masimum. 
Amplitude. 
Annual. 
January, 6 
•13 
Semi-annual. . . . | 
February, h —March, a - 
August, h —September, a 
CO 
o 
It follows from this examination, imperfect as it is, (1) that in slight earthquakes 
both periods are more marked than in destructive ones, but that this is especially the 
case with the semi-annual period, the amplitude of the annual period being increased 
1’2 times, and that of the semi-annual period 3‘4 times; and (2) that the maximum 
epochs of the annual period are almost reversed. 
15. JI'panese Earthquakes 18 8 5-18 89.—The organization of earthquake statistics 
in Japan is under the direction of the Imperial Meteorological Bureau. Beports are 
issued yearly, and abridged translations of these for the years 1885-1889, have been 
published by Professor S. Sekiya and Professor J. Milne (see §51). Professor Mii.ne has 
classified the earthquakes in monthly groups according to the areas disturbed by them. 
The results are given below, but it should be remembered that the duration of the 
record is short; also that the areas given are land areas only, and many Japanese 
earthquakes originate beneath the sea. 
(1.) Earthquakes disturbing an area less than 100 square ri (1 square ri = 5‘9 square 
miles). Number of earthquakes, 2256. 
Period. 
Alasimum. 
Amplitude. 
Annual. 
Semi-annual. 
September, h —October, h 
f March, a 1 
i September, a j 
•14 
•12 
(2.) Earthquakes disturbing an area less than 1000 square ri and greater than 
100 square ri. Number of earthquakes, 565. 
Period. 
Maximum. 
Amplitude. 
Annual. 
February, b —March, b 
•17 
Semi-annual. 
f June, a J 
[ December, a J 
•16 
(3.) Earthquakes disturbing an area greater than 1000 square ri. Number of 
earthquakes, 176. 
