wash over it. Thus the curious ring of land is gradually formed,
and affords a nutritive soil, in which cocoa-nuts, on being cast
ashore, germinate and grow to be large trees. Other seeds, wafted
by the waves or carried by birds, also begin to grow, until the
whole surface becomes covered with vegetation. Then comes man and
builds his habitation upon those fertile spots, and finds in them
an agreeable and convenient abode, well suited to those who are
accustomed to live by fishing and other simple means.

You will thus perceive that the connexion between the atoll and the
volcano consists in this--that while the coral builds up the reef,
the volcano beneath ingulfs the island and causes it to sink down.
In some instances, however, the volcano, after a while, reverses
its action, and raises up the island with the reef upon it. In such
cases, the coral reefs are seen standing out of the water, forming
perpendicular cliffs several hundred feet in height. Then also the
interior of the island becomes once more dry land, and that, too,
of great fertility.

[Illustration: Mount Erebus.]

Almost due south of that region, in the Pacific, where the coral
islands abound, but at a great distance from them, and considerably
within the limits of the Antarctic zone, lies South Victoria. Here,
in lat. 76 degrees S., Captain Ross discovered, in 1841, two
volcanoes, which he called Erebus and Terror, after the names of
his two ships. Of the former, which is the higher of the two, a
view is given in the annexed woodcut. It is covered with perpetual
snow from the bottom even to the tip of the summit. Nevertheless,
it is continually sending forth vast columns of vapour, which glow