Postscript. 213
furnish no data for determining the depth of the
initial disturbance.
80. The shock occurred at the origin probably between 9.17
and 9.18 a.m. G. M. T., April 22nd, 1884.
31. Observations as to the time of the occurrence at different
stations were not sufficiently accurate to have been
made use of for determining the epicentrum.
32. The mean velocity of propagation of the shock, as deduced
from the most trustworthy of the time-records, was
about 9000 or 10,000 feet per second (nearly 7000 miles
an hour). This calculation, owing to the uncertainty
of the time-observations, must be regarded as only
roughly approximative.
33. With reference to the general direction of propagation
of the disturbance at different stations, the personal
experiences of observers have not been considered
sufficiently trustworthy evidence. The more important
observations of the direction, as given by the swing of
freely-suspended objects, the projection of bodies, &c.,
agree as fairly as might be expected in indicating an
epicentrum coincident with the main axis of damage.
The directions of propagation as deduced from the
direction of twist in chimneys, and the plane of
oscillation of the pendulums of clocks which were
stopped by the shock, are of no value.
34. The shock probably originated beneath the villages of
Abberton and Peldon, and apparently suffered a con-
siderable amount of reflection at Wivenhoe.
Postscript.
The Earthquake recorded at Leeds.
While the foregoing report has been going through the
press we have learnt, through a communication to the 'Leeds
Mercury,' that the shock recorded itself in that town on the
tracing-paper of a recording barometer, although, as far as we
have been able to ascertain, the movement itself was not
perceived by anyone. The following is the communication
in question:—