General Characters of the Disturbance. 41
With regard to the succeeding shocks which are stated
to have occurred, the same remarks respecting the want
of confirmation are applicable, and the only account to
which credence can be given is that of a slight shock
about 5 a.m. on June 24th, which has already been re-
corded on the authority of Mr. Henry Laver, of Colchester.
This gentleman, well known as a skilful observer, in-
formed me that he and all the inmates of his house were
simultaneously awakened at the time mentioned, and I had
the opportunity of verifying this statement by personal
inquiry, during the visit of the Essex Field Club to Col-
chester, in August, 1884.
Miscellaneous effects.—Among the features which the present
disturbance displays, in common with other earthquakes,
must be mentioned the sudden shock or blow felt on ships
and boats on the Colne and Blackwater at the time, and
which has always been a familiar experience to observers who
have happened to be afloat near an earthquake centre. This
effect appears to be attributable to the fact that liquids are
incapable of transmitting transverse waves,21 so that the
latter would as it were be filtered off, and the normal wave
alone strike upwards through the water.
Among other miscellaneous effects, attention may be
directed to the statements of several observers who experi-
enced sensations of giddiness and nausea, an effect of earth-
quakes which has frequently been noticed,22 and which in
extreme cases has been known to produce actual vomiting.
It will be seen also that several observers who were out of
doors walking at the time felt nothing of the shock, although
in houses close by the effects were most marked, in some
cases even structural damage having been witnessed by
persons who were not themselves sensible of the movement.
This experience, which has also been previously recorded,23
21 See Prof. Ewing's Memoir, loc. cit. p. 1.
22 Mallet, Brit. Assoc. Rep., Leeds, 1858, p. 133.
23 Milne, Trans. Seism. Soe., Japan, vol. i. part 2, p. 89. The author
remarks also that " an earthquake which would almost shake a city down
might, if we were dwelling in tents or outside brick or wooden dwellings,
be on many occasions passed by almost unnoticed."