All
depends upon that, for if we do not get into a sheltered part we can
only make a few short visits."

The wind began to fall so light when they had sailed a few miles, that
it was evident that before long they would have a similar calm to that
which they had experienced on the previous day.

"My brain's a little foggy about where the opening in the reef is," said
the captain soon after breakfast; "and I am rather anxious to get inside
before the wind drops, for one never knows what weather one is going to
have in these latitudes at this time of year, especially after a calm."

"Are you sure there is an opening in the reef?" asked the doctor
anxiously.

"Oh yes, I'm sure of that," said the captain, "for I rowed through it
and landed; but it's some years ago, and one can't recollect everything.
Suppose you go aloft, Bartlett, with the glass, and see what you can
make out."

"May I come with you, Mr Bartlett, and bring mine?" said Jack eagerly.

"Glad of your company," replied the mate. "You take one side and I'll
take the other."

"Ay, that will be best," said the captain; "for our main-top is not like
that of a man-o'-war."

Sir John looked a little anxious, but he said nothing, and stood
watching as Jack went to the starboard main shrouds and began to ascend
rather awkwardly but with a quiet determination which soon landed him in
the little top, where he and the mate levelled their glasses, and began
to trace the edge of the reef where the great rollers were foaming, but
nothing was visible, till all at once Jack said--

"What will the opening be like?"

"A spot where there is no foam--no breakers curling over."

"I've found it then," said Jack quickly, "but it seems to be a very long
way off."

"I'm afraid you are mistaken," said the mate, who repeated the process
of sweeping the reef with his glass. "My eyes are pretty good ones, but
I can make out nothing but breakers. Try again, and see if you see the
place now."

Jack had not taken his double glass--a very good one presented to him by
his father--from his eyes, and a minute had not elapsed before he said--

"Yes, there it is: a dark bit in the white rollers. It's a long way
off, but I can see it quite plainly."

"Make anything out?" cried the captain anxiously, as he watched them
from the deck.

"I can't, sir," replied the mate, "but Mr Jack here says he can see it
quite plainly."

"Well done, young mariner," cried the captain. "Good