PREFACE.
The present report upon the most serious natural calamity that
has befallen the county of Essex within the historical period has
occupied the greater part of our scanty leisure time since its
occurrence, and to many of our readers it may appear that the
volume which we now offer as the result of our labour is out of all
proportion to the magnitude of the event. In detailing the facts of
the earthquake at such length we have been actuated by the desire
of producing a report which we think we may venture to regard
as typical of a "local investigation" in the sense insisted upon
by the Corresponding Societies Committee of the British Asso-
ciation for the Advancement of Science. We are of opinion that
such investigations should deal as exhaustively as possible with
the facts relating to any particular subject, and at the same
time that the legitimate conclusions should be drawn from these
facts with especial reference to the district over which the local
society extends its operations. This position we have endeavoured
to take up in the following report, although of course a phe-
nomenon affecting such a wide area as the present earthquake
passes beyond the province of a purely local subject, and we can
only express our regret that we have not been able to secure to a
greater extent the co-operation of other societies in neighbouring
counties. It may, however, be fairly pleaded that earthquakes of
this magnitude are of such rare occurrence in our country that
seismology as a subject is hardly pursued, and that very few
persons know how or what to observe under such circumstances.
It is hoped that our report may for this reason be found of some
service to seismologists in general, although we can but sincerely
wish that their opportunities for investigation may be few and far
between. The whole subject is of such great complexity, and its
practical investigation is surrounded by so many difficulties, that it
must as yet be regarded as one of the most infantile of the modern
branches of Science. It is only by the labours of those who, like