the views of several authorities as to the distribution of
Earthquakes in time and in space--occupy the first 46 pages of this
Report.

It then proceeds to discuss the distribution in time and in space as
deduced from the full base of the great catalogue.

The results as to time are reduced to curves, and those as to space (or
distribution over our globe's surface) to the great seismic map
(Mercator's projection), upon which and in accordance with certain
principles and conventional laws, which admit of the indication of both
intensity and frequency, all recorded Earthquakes have been so laid down
as to present a real indication of the distribution of seismic energy
for the whole historic period and all over the world.

The original of this map, which also shows the Volcano (size, about 7
feet by 5 feet), remains for reference in the custody of the Royal
Society. A reduced copy was published with the Report, and to a still
more reduced scale has been reproduced in other places. It is impossible
here to do more than refer to a few of the more salient points.

As regards distribution in time, durational seismic energy may be
considered as probably constant during historic time, though it is
probably a decaying energy viewed in reference to much longer periods.
It does not appear of the nature of a distinctly periodic force.

1. Whilst the minimum paroxysmal interval may be a year or two,
the average interval is from five to ten years of comparative
repose.

2. The shorter intervals are in connection with periods of
fewer Earthquakes, not always with those of least intensity,
but usually so.

3. The alternations of paroxysm and of repose appear to follow
no absolute law deducible from these causes.

4. Two marked periods of extreme paroxysm are observable in
each century (for the last three centuries), one greater than
the other--that of greatest number and intensity occurring
about the middle of each century, and the other towards the end
of each.

As respects season, there appear distinct indications of a maximum about
the winter solstice, and equally so of a minimum rather before the
autumnal equinox. It is not improbable that there is a remote relation
between Earthquakes and the annual march of barometric pressure.

We may expect, at present, one great Earthquake about every eight
months, and were we possessed of a sufficient report from all