n increased.

Then of a sudden the stump of a mast sank into the water, there was a
still greater agitation and a mass of broken timbers shot up into the air
and then fell back, and went floating away on the tide.

"That's about the last of her," said Captain Storms, "or, at any rate, you
won't go into the cabin again. You've made your last visit to the wreck,
and if any one ever gets that money he'll have to dive for it. You can be
thankful that you went there when you did."

"So I am," said Jack. "Come on, Dick, pull away from here."

CHAPTER X

A THRILLING ENCOUNTER

Returning to the yacht first for the captain to get aboard, Jack and
Percival then took the boat and went to the outer bay on a little
exploring trip of their own, the rest not caring to make any more
explorations at that time.

The boys guided the boat along shore not too near the rocks, both keeping
watch for any nook which might prove of interest or afford an opportunity
for an adventure of any sort.

There was a short, keen-bladed hatchet to cut their way through the
thicket if necessary when they went ashore, and Percival had a rifle with
which to shoot any game they might come across, both being placed on one
of the forward thwarts.

Jack was provided with his pocket flashlight in case they went into dark
places, and Dick had a revolver in his pocket, declaring that this might
be of as much use as the torch in case they came to close quarters with an
enemy, no matter of what sort.

As they were rowing at a lazy rate, keeping up a slow, even stroke, Jack,
who was keeping a lookout on the shore and steering at the same time,
suddenly said, looking toward a mass of rocks which they had just come
abreast:

"There looks to be a sort of cave in there, Dick. At any rate, there is a
hole which seems to run in to some little distance. Suppose we explore it
and see how far we can go."

"I'm in for anything that you are, Jack," replied Dick.

"All right, pull ahead, not too fast, and we'll have a look at the place."

"Pull ahead it is, Jack."

Jack was in the bow and he now steered the boat toward the opening in the
rocks, which was quite big enough for them to enter, and they went on at a
slow, steady gait, presently gliding into the water cave, for such it
seemed, with plenty of room above and on both sides.

Jack turned his head now and then to see how they were progressing and if
there were any obstructions in the way, and pres