vi Preface.
Profs. Milne and Ewing, have had in Japan such frequent oppor-
tunities of measuring and recording earthquake-shocks that we can
ever hope to arrive at a true knowledge of the laws governing these
phenomena. We have lost no opportunity, therefore, in this
report of interpreting the observations by the light of the results
which have been achieved in Japan by means of specially-
constructed instruments in the hands of skilful observers, so that,
although nominally concerned with one earthquake only, we are
not without hope that the present work may be considered to
contain sufficient general matter to establish its position as a
guide to those about to take up the study of seismology.
One point in connection with the report which will doubtless
strike our readers is the general untrustworthiness of what may be
called common-place observations in any attempt to submit an
earthquake to exact mathematical treatment. If our labours serve
only to emphasize this inadequacy of non-instrumental methods of
observation, we feel that our efforts will not have been altogether
exerted in vain. We can only add that we have made as much out
of the materials at our disposal as we possibly could; whether we
have made too much of our materials and have drawn unwarranted
inferences we must leave to the judgment of our scientific readers.
In conclusion, we can but express the wish that this task had
been taken up by some more qualified specialists than we can lay
claim to be considered in the present subject. As a local phe-
nomenon, we felt it our duty, however, to represent to the Essex
Field Club the necessity for taking up the subject, the more
especially as the occurrence received no official recognition, and
we considered that in the interests of British Science such a
visitation should not be allowed to pass without being fully re-
corded. On behalf of the Club we have striven to perform this
duty in the midst of other occupations, and whether we have
succeeded in adding anything of permanent value to Seismological
science or not, we cannot but feel satisfaction in knowing that the
great Essex earthquake of 1881 is no longer an unwritten chapter
in the history of the county.