476 C. G. Rockwood, Jr.—Japanese Seismology. 
(ong; extending hon Kamschatka to the ie ee ore 
estion is ventured then that this and other earthquakes are 
active vent; “that this line is still an to open for 
— “sa still farther north ;” and “that beneath Yedo bay 
ther a point where volésitio’ agencies are endeavoring to 
forse a eye 
These conclusions as to the probable origin of the frequent 
earthquakes are further confirmed by later observations of two 
different sorts.* Prof. Milne in Tokio, and Mr. W. H. Talbot 
in Yokohama, have made careful time observations, using 
clocks with sensitive apparatus to stop them at the instant of a 
shock and keeping the clocks regulated by daily telegraphic 
comparisons. ‘The result is that the sioks are usually felt in 
Yokohama from fifteen to thirty seconds earlier than in Tokio, 
indicating an origin nearer to the former place. Again seis- 
miles of Yokoham ma: on ‘Jan. 22, 1881, the intersection was 
four miles south-southeast of Yokohama; and on Jan. 24, 1881, 
the intersection was seven miles south-south west ¢ the same 
place,—again all indicating an origin near Yokoha 
ut perhaps the most interesting of recent vedeles was ob- 
tained from the earthquake of March 8, 1881, some notest on 
which were read before the Seismological Society on March 238d, 
by Prof. Milne. At this shock a complete bis of the earth- 
motion for over twenty-five seconds was § ured. The instru- 
ments used were a pair of “bracket ring’ Lanleucarabbis writing 
upon a slip of smoked glass, for the two horizontal components, 
and a water vessel with flexible bottom * the vertical compo- 
nent, The bracket-ring machines (No. 1 and No. 2), were 
purposely placed so as to record vibrations at right angles to 
and in the direction of a line joining Tokio and Yokohama 
23° 
(S. 
No. 1 showed a decided motion, there being about seven 
vibrations in five seconds, or one complete vibration in $ of a 
second. The greatest indicated motion in this direction is 
about 1° millimeters. 
No. 2 indicated very slight but sensible motion 
No. 3 for vertical motion showed ae six distinct waves in 
a space indicating twenty-five seconds of 
These records, confirmed as they are es pahe register of Pal- 
mieri’s instrument and of eleven different pendulums, show 
* Japan Gazette, Feb. 5, 1881. + Japan Gazette, April 2, 1881. 
