sharks were not there at the time, or
that the number and energy of the swimmers frightened them, we cannot
tell, but each man reached a log or plank in safety, and began pushing
it towards the reef. It was when they drew near to this that the trial
of their courage was most severe. The excitement and gush of daring
with which they had plunged in was by that time expended, and the slow
motion of the logs gave them time for reflection. O'Rook's lively fancy
troubled him much.

"If the baists would only attack a man in front," he muttered, "it's
little I'd mind 'em, but to come up behind, sneakin' like--hooroo!"

At that moment a branch of coral, which projected rather far from the
bottom, touched O'Rook's toe and drew from him an uncontrollable yell of
alarm. Baldwin Burr, who swam close behind, was humorously inclined as
well as cool. He pushed the plank he was guiding close to his comrade's
back, dipped the end of it, and thrust it down on O'Rook's legs.

The effect was even more powerful than he had hoped for.

"A shark!--a sha-a-a-rk!" howled O'Rook, and dived under the broken
main-yard, which he was piloting ashore. Coming up on the other side,
he tried to clamber on it, but it rolled round and dropped him. He went
down with a gurgling cry. Again he rose, grasped the spar with his left
arm, glared wildly round, and clenched his right hand as if ready to hit
on the nose any creature--fish, flesh, or fowl--that should assail him.

"Take it easy, messmate," said Burr in a quiet tone; "sorry I touched
you. Hope it didn't hurt much."

"Och! it was you, was it? Sure, I thought it was a shark; well, well,
it's plaised I am to be let off so aisy."

With this philosophic reflection O'Rook landed with his piece of timber.
Enough of material was soon collected to form a raft sufficiently large
to ferry half of the party across the lagoon, and in two trips the whole
were landed in safety on the island.

"You don't mean to tell me, Jack," said Baldwin Burr, "that this island
was made by coral insects?"

"Yes, I do!" said Jack.

"From the top to the bottom?" asked Burr.

"From the bottom to the top," said Edwin.

Baldwin asked this question of the philosopher during a pause in their
labours. They were, at the time, engaged in constructing a new bower
for Polly among the flowering shrubs under the cocoa-nut palms. Polly
herself was aiding them, and the rest of the party were scattered among
the bushes, v