will understands is made by very small sea
insects, who form it for their habitation," he observed. "God has given
them the instinct to build in certain ways and places, just, as if they
knew what they were about, and that they were building up an island fit
to be inhabited by human beings. They seem to choose the tops of rocks
from one hundred to two hundred fathoms below the surface, for the
foundation of their structure. They have toiled on for ages, placing
storey upon storey, till the surface has been reached, when they have
been compelled to cease; for out of the water, whence they draw their
materials--their bricks and mortar, so to speak--they can do nothing.
The outer edge breaks the force of the sea, but not altogether. Enough
strength is exerted during storms to tear off the outer edge of the
coral, and to throw it on the top of the wall. Seaweed and driftwood
and dead fish are next thrown up on it, which, when they decay, form
soil. Birds next come and rest on the island, and further enrich the
soil. They bring seeds of grass and small shrubs at first, and
afterwards of larger trees, which take root and spring up, and in their
turn, when they decay, form more earth to nourish a larger species of
trees, such as the tall palms, and cocoa-nut, and pandanus, which we
have seen growing on them. The sandy beach is formed of the broken
coral and shells, ground small by the constant action of the waves. I
have heard that the lagoons are often very deep, so that the island is
exactly like a circular wall built up from the bottom of the sea, or
rather from a rock far down in it."

Mr Martin promised the boys that he would tell them more about other
islands which they were likely to visit another time. He had also with
him some most interesting accounts of the progress which the
missionaries had made among the heathen in those seas, which he promised
also to give them.

People were seen on the shore, though no habitations were visible, and
Captain Bertram wished to communicate with them. While the frigate was
hove to, to leeward of the island, two boats were sent on shore under
Mr Charlton's command. Ben went in one of them. A native of Tahiti,
called Tatai, had been shipped at Callao to act as interpreter, as
without one very little intercourse could have been held with the
natives. Ben had told him all about Ned, and how he hoped to find him
on one of the islands they expected to visit Tatai said that