"It is possible they may suspect something and come back again," said
the mate, "but it is hardly probable."

"Are they likely to send any friends to take us off?" asked the
captain, with a quizzical look.

"Not to any great extent. They will be sure to give us as wide a
berth hereafter as possible. In the meantime, I propose that we
investigate."

The two rose to their feet, and, lugging the armor between them,
moved off toward a point whose location was as well known to them as
if they had spent years upon the atoll.

While they were thus walking, the mate, who was much the better-educated
man, said:

"This pearl-hunting is a curious business. Those specimens that I
brought up were the genuine species, and yet they have very few or no
pearls among them. It must be because the conditions are not favorable
for their creation or development, while, at the place we are about to
visit, the mollusks are the same, and yet there are conditions
existing there which cause an abnormal growth of the precious
jewels."

"Did you make a careful examination of those other oysters?"

"Yes. As I told you, they are genuine, but they have no pearls of any
account, the conditions being unfavorable for their formation. You
know the pearls grow within the oysters, being composed of slimy
secretions deposited around some foreign substance that enters them.
It may be that a peculiar action of the tide drives a grain of sand
into the mollusks, where we are to visit--though that is all
conjecture."

But Mate Storms, who was only fairly launched out in the discourse
upon pearls, was here interrupted by the captain exclaiming:

"This must be the spot."

The particular bank had been designated so clearly that there could be
no mistake, and had the chart, or map, fallen into the hands of the
mutineers, they would have discovered the trick played on them in an
instant. The spot was a peculiar one where the two friends stopped.
Instead of being partly landlocked like the other, it opened out
fairly upon the sea, and appeared to be entirely unprotected from the
force of the breakers, which boomed against the beach.

It would have been supposed naturally that the true course was for the
fishermen to go out in a small boat, and make their explorations from
that, but Grebbens had instructed the captain that the formation was
so peculiar that nothing would be gained by this course. The shore
sank like the side of a wall to a considerable d