e as rapidly as it sank.
This peculiarity is well worth remarking. The eminent physicist Mallet
speaks thus (we follow Lyell's quotation) about the waves which
traverse an open sea: "The great sea-wave, advancing at the rate of
several miles in a minute, consists, in the deep ocean, of a long, low
swell of enormous volume, having an equal slope before and behind, and
that so gentle that it might pass under a ship without being noticed.
But when it reaches the edge of soundings, its front slope becomes
short and steep, while its rear slope is long and gentle." On the
shores visited by such a wave, the sea would appear to rise more
rapidly than it sank. We have seen that this happened on the shores of
the Samoa group, and therefore the way in which the sea rose and fell
on the days following the great earthquake gave significant evidence
of the nature of the sea-bottom in the neighborhood of these islands.
As the change of the great wave's figure could not have been quickly
communicated, we may conclude with certainty that the Samoan Islands
are the summits of lofty mountains, whose sloping sides extend far
toward the east.

This conclusion affords interesting evidence of the necessity of
observing even the seemingly trifling details of important phenomena.

The wave which visited the New Zealand Isles was altogether different
in character, affording a noteworthy illustration of another remark of
Mallet's. He says that where the sea-bottom slopes in such a way that
there is water of some depth close inshore, the great wave may roll in
and do little damage; and we have seen that so it happened in the case
of the Samoan Islands. But he adds that, "where the shore is shelving
there will be first a retreat of the water, and then the wave will
break upon the beach and roll far in upon the land." This is precisely
what happened when the great wave reached the eastern shores of New
Zealand, which are known to shelve down to very shallow water,
continuing far away to sea toward the east.

At about half-past three on the morning of August 14th the water began
to retreat in a singular manner from the port of Littleton, on the
eastern shores of the southernmost of the New Zealand Islands. At
length the whole port was left entirely dry, and so remained for about
twenty minutes. Then the water was seen returning like a wall of foam
ten or twelve feet in height, which rushed with a tremendous noise
upon the port and town. Toward fiv