58
The East Anglian Earthquake.
Birch, about two miles W.S.W. of Kingsford, appears to
be the western limit of structural damage in this direction.
Writing from Birch School, Mr. Joseph Wilkins gives the
following experience :—
" I was standing in an erect position in the midst of a room
65 feet in length, having a general direction north and south,
but which inclines slightly westward. The time was precisely
9.20, and the first intimation of the shock was a loud, but
peculiar rumbling sound—a something between the report of
an explosion and thunder, or rather a combination of the two.
This preceded the wave by about one and a half seconds,
and continued about three seconds, during the latter part of
which time I felt the floor heave beneath my feet, and a
distinct waving or swaying motion from south to north, very
similar to the deck of a vessel heaving with a swell of the sea.
There was certainly a repetition of the wave ; but whether a
third followed I cannot be positive, though I am inclined to
believe there was. If so, however, the third wave was slight
compared with the first. The duration of the waving was
about three seconds, so that the whole duration was seven or
seven and a half seconds. I was inclined at first to guess the
time at 15 seconds, but comparing, as I did soon afterwards,
the duration of the shock by the hand of a watch marking
seconds, I feel certain that about half that time was as
nearly correct as possible. I distinctly experienced the effect
of slight ' nausea,' of which I see others have spoken."
A clock with pendulum swinging E. and W., which had
been stopped the previous night, was set going by the shock.
Mr. Wilkins has been good enough to supply, at my request,
the following additional particulars :—
" The clock mentioned in my letter was a large brass
skeleton time-piece, standing on a chiffonier in my drawing-
room, against a wall running E. and W. It is of English make
and escapement, having a rather heavy flat brass pendulum,
measuring 81/2 inches from the hanging stud and swinging
from E. to W. I had stopped it the previous night at 10.20.
" The ceiling of the room adjoining seemed to be ' ricked '
with cracks running in a rather zig-zag direction towards the
N.E. corner. This room also occupies the N.E. corner of my
house. I was myself in the school-room at the moment
of the shock. This room is 65 feet long, standing almost due
N. and S. (slightly inclining N.E. and S.W.). It is furnished
with seven sets of desks in parallel groups of three each, five