AND SEMI-ANNUAL SEISMIC PERIODS. 
1135 
Japan. 
51. ‘Trans, of Seismol. Soc. of Japan/ vol. 10, 1887, p. 61 ; vol. 13, Part 1, 1889, 
p. 93; vol. 15, 1890, p. 101 ; vol. 16, 1892, pp. 56 and 83. 
Duration of record, 1885-1889. Number of earthquakes, 2997. 
This record has already been discussed in § 17, with reference to seismic intensity. 
The early epoch of the annual period is due to the very large number of shocks 
disturbing an area less than 100 square ri. 
Period. 
Maximum. 
Amplitude. 
1 
i Annual. 
1 
1 
! Semi-annual .... 
i 
Annual barometric . 
October, h 
r March, a 1 
\ September, a J 
December, b 
•08 
•07 
52. '"'Tokio .—Professor J. Milne, ‘Trans, of Seismol. Soc. of Japan,’ vol. 2, 1880, 
pp. 4-14, 39; vol. 6, 1883, pp. 32-35; vol. 8, 1885, pp. 100-108; vol. 10, 1887, 
pp. 97-99 ; vol. 15, 1890, pp. 127-134. Also (for the earthquakes recorded by the 
Gray-Milne seismograph) ‘Brit. Assoc. Pep.,’ 1886, pp. 414-415 ; 1887, pp. 212-213 ; 
1888, pp. 435-437; 1889, pp. 295-296 ; 1890, pp. 160-162; 1891, pp. 123-124; 
1892, pp. 93-95. 
Duration of record, 1876-1881 and 1883-1891. Number of earthquakes, 1104 
(fig. 14). 
Professor Milne’s record of earthquakes felt in Tokio, begins in September, 1872. 
From the end of 1875 until the present time, the earthquakes were all registered by 
instrumental means. Palmebi’s seismograph was used until April, 1885, and the 
Gray-Milne seismograph after that date. At the end of the year 1882, observations 
were suspended during the removal of the instrument; this year is accordingly 
omitted. 
Fig. 14. 
Tokio (Milne). 
