But if we are alarmed by this list of British
earthquakes, and turn to see how our neighbours
fare, we shall have little comfort beyond that of
finding that we are no worse off than they. In
the Scandinavian peninsula and Iceland, the
numbers are rather higher, but not much: 111
have been recorded in those countries as felt during
the last century, and 113 in the first half
of the present. In Spain and Portugal 93 in
the eighteenth, against 85 in the nineteenth;
in France, Belgium, and Holland together, the
figures are 308 and 292, while in the Basin of
the Rhine and Switzerland, no less than 557
earthquakes are recorded since the beginning of
the ninth century, of which 52 took place in the
sixteenth, 120 in the seventeenth, 141 in the
eighteenth, and no less than 173 in the first half
of the present century. The Italian peninsula
and the Eastern Mediterranean we might expect
to be troubled with disturbances of this kind,
owing to the large amount of volcanic action
constantly taking place there; but, excluding
these countries, where, indeed, upwards of 800
earthquakes have taken place within the last
fifty years, we find a total of 2156 earthquakes
recorded as felt at various places in Western
Europe since the beginning of the Christian era:
of which 773 belong to the present century.

Now, as we cannot suppose that we have
anything like a complete account of all that have
taken place, we may fairly assume that in these
districts where, with the exception of Iceland,
there is nothing of the nature of volcanic disturbance,
there really must be, at least, one earthquake
every six weeks, and perhaps more!

It is not the case that in this calculation the
half-dozen or dozen shocks connected together
as parts of one real disturbance are counted
separately; on the contrary, where it seemed
admissible, a whole group of small movements,
spread over several days, is recorded as one
earthquake. Such small shocks have been
frequently felt at Comrie in Scotland, and
elsewhere, and are always recorded in sets.

It is quite true that many of these shocks are
inconsiderable, and that a disturbance sufficient
to affect human life and property to a serious
extent is unknown in the history of our country.
Precisely the same remark might, however, have
been made by the inhabitants of Lisbon at nine
o'clock on the morning of the 1st November,
1755, although before the clocks left uninjured
had struck the hour of ten, a large part of the
city had been destroyed, and many thousands of
human beings had passed away to their account.

The earthquake that destroyed Lisbon,
produced almost as much mechanical disturbance in
many places along the coast of Portugal and
Spain, as it did at Lisbon; and, indeed, produced
almost as much mischief on the shores of
Morocco as on those of Europe. It reached northwards
so far as to include Iceland, and westwards
to the West Indian Islands and Canada. Its
range in the interior of Europe included Italy,
Switzerland, Bohemia, and the Baltic; and
southwards it extended far into Africa. The
exact spot where the first disturbance took place
was some distance out in the Atlantic, and there
is nothing known that could have pointed to
that spot, rather than any other, as one where
such an event would originate.

England, then, appears to belong to a large
tract of country, some of it above, and some
under water, the whole of which is subject
constantly to earthquake disturbance, and any part
of which seems occasionally liable to movements
of this nature, so considerable as to rival the
most important on record. We enjoy no
immunity from the most sudden, the most irresistible,
the most destructive, of nature's powers.
Another such shock as the Lisbon earthquake
may happen this or next year. It may not
happen in this country, but it may originate
beneath our own metropolis or under the ocean.
It may originate near us or a thousand miles away
from us, but we are not the less certainly living
over a mine ready to be sprung. No one can tell
when or where the fatal match will be applied.

Let us look again to our figures, to see if we
can obtain further information. Taking all
recorded earthquakes as the basis of calculation,
we find a list of nearly seven thousand separate
events ranging over three thousand four
hundred and fifty years. Of the whole number,
most of those recorded in early times were
very serious, and are mentioned for that reason
in history as extraordinary and exceptional
events. Most of those mentioned within the
last century, on the other hand, have been
slight, but, à fortiori, the severe ones have also
been spoken of, and we have generally had
detailed accounts of them. Thus, although the
materials for calculation are imperfect, yet the
nature of the imperfections is known, and
valuable comparative results may be obtained.
Out of the whole number (6831), we have
787 distributed over eighteen centuries
terminating in the year 1500; 2804 between the
years 1500 and 1800; and the rest (2227)
during the first half of the present century.
From the most recent observations we obtain
a general average of one earthquake in some
part or other of the earth's surface every
six days, and of these it is further calculated
that one fortieth part (one earthquake every
eight months) is of "serious importance," or,
in other words, is one in which whole cities and
towns, or large portions of them, have been
reduced to rubbish, and many lives lost. In the
vast tract subject to earthquakes, of which our
islands form a part, the proportion of serious
disturbances would probably be below the
general average; but if, instead of one great
earthquake in eight months there be only one
every quarter of a century, there is yet sufficient
cause for alarm.

It occurred to M. Perrey, to tabulate his
earthquakes in various ways, in order to discover
whether any relation existed between them
and the moon's position—whether temperature
had anything to do with their recurrence and
sundry other matters. He soon found that
taking four years, during which his material
was most ample and most accurate (1844 to