14 The East Anglian Earthquake.
The great earthquake of November 1st, 1755, by which
Lisbon was destroyed, and which shook an area of the
earth's surface four times greater than the whole of Europe,
was felt in many parts of this country, and tidal disturbances
were produced round our coasts. The inland waters were
also thrown into agitation in many parts of England4 and
Scotland. Amongst these records the following communi-
cation to the Royal Society relating to the county of Essex
will be of local interest:—
"Agitation of Water in Rochford, Essex, Novr. 1, 1755, in a
Letter from the Rev. Mr. Thomlinson, to the Rev. Dr.
Sykes.
" Christmas-day, 1756.
" It will surprise you to hear that we had some symptoms
of an earthquake at this place, on the very same day, and
about the same hour, in which the late dreadful convulsion of
the earth was in so particular a manner fatal to Portugal.
One instance of it was of a pond in a close of Mr. Sly's
adjoining the churchyard ; where the water was observed by
Mr. Sly himself to flow a considerable way up the mouth of
the pond, and then returning to flow up the opposite side,
repeating this sort of motion for about a quarter of an hour.
What is further remarkable in this case is that, at the very
time of this fluctuation, Mr. Sly had the curiosity to
examine the condition of two other ponds, which are but a
small distance from the former, and found them both very
still and quiet. It may deserve notice, that the motion
of the water in Mr. Sly's pond was only from East to West
and from West to East alternately. Whether the fluctuation
in those other ponds, which have been mentioned in the
newspaper, was the same, it may be worth while, it will at
least be a matter of curiosity, to inquire, Mr. Sly's pond is
very large and almost round. Its mouth is on the East side.
The two neighbouring ponds lie in length from North to
South, and are comparatively very narrow in their breadth
from East to West, which may in some measure account for
the motion of the water in them, if there was any, being less
4 Amongst many other places where this oscillation of the water was
observed was Shirburn Castle, Oxfordshire, where the present earthquake
was also felt. I am indebted to the Countess of Macclesfield for sending
me the extract relating to this observation, and I only regret that want
of space forbids my quoting it in extenso. See Phil. Trans., vol. xlix.,
p. 368. For an explanation of these phenomena see a paper by Prof. J.
Milne, ' Nature,' vol. xxvi., p. 629 (Oct. 26th, 1882.