C. G. Rockwood, Jr.—Japanese Seismology. 477 
clearly that the main vibration in the vicinity of Tokio was in a 
general east-and-west direction e time observations, and 
other considerations also, indicate that the origin of the shock 
was in the faulted region near Yokohama. Hence Milne i is led 
to the conclusion that the ibneome observed were transverse 
to the direction in which the wave was mo es instead of 
tions are the more persistent and are felt to a greater distance 
than the longitudinal. Moreover, if the earthquake wave orig- 
inated by the tearing open of a fissure in the rock and the 
sliding of the surfaces upon each other, a shearing force would 
be exerted which might produce a wave of distortion without 
any accompanying wave of compression 
e Japan Gazette of July 23, 1881, contains a note of some 
interesting observations on an ‘earthquake of July 5, 1881, 
showing that the motion of the ground Bein conn. in 
direction during the same shock. The records were made by 
ray’s Double- peecses Ssiemeepe” Hine upon a aod 
plate. Prof. Milne 
“Near to the Roe beesea of the shock the motion was 
N. 112° E. One and a half seconds after this the direction of 
motion appears to have been N. 50° E. In three-fourths of a 
second more it gradually changed to a direction N. 145° E. ; 
and after a similar interval to N. 62° E. Half a second after 
this it was N. 182° E., and four pose later the motion was 
again in the original direction, viz., N. 112° E. ‘Phere appear 
to have been at some portions of the shock not more than four 
vibrations per second, at other portions there may have been as 
any as ten. The greatest amplitude of motion does not 
appear to have reached one millimeter.” 
The records of the various instruments agree in the indica- 
ed 
EK. Knipping * with Dr. Wagner's apparatus only two exceeded 
25 mm. in amplitude, and a similar fact has been incidentally 
pin mt in respect to several of the earthquake shocks 
spoken of above. 
To conclude our review of what has been done in Japan in 
= department of research, the results achieved can perhaps 
st be sammed up in the words of Professor Milne himself in 
* Transactions Seismolog. Soe. of Japan, vol. i, part I, p. 71. 
. 
