out what the mystery was!
But I didn't count on the cannon."

"No, it wouldn't have been safe to risk a shot. We might have sunk."

"But I'll not give up!" exclaimed Frank determinedly. "We've got some
clues now, and we can follow them. Just notice which way they're
sailing, Andy."

"What good will that do?"

"I intend to circle back in a short time, and see if I can pick them
up. It's one thing for him to order us back, but we have just as much
right on the ocean as he has, and he can't keep us off. If we stay far
enough back they can't see us, and we can find out where they're going."

"Where do you think they're heading for?"

"Give it up, but I know one thing. It's evident that this man, whoever
he is, wants to keep out of observation. That is proved by the fact
that he once had this damaged motor boat in tow of another gasolene
craft, and for some reason he gave it up. He may have anchored it in
some out-of-the-way place, and has only just now gone for it. That's
what he wanted of Jim Hedson's boat, but we spoiled his plans. Now he
has another sailing craft to tow the prize in."

"I believe you're right, Frank, but where do you suppose he's taking
it?"

"Give it up, but I'm going to keep on the search for him. If there's a
chance of bringing back Paul's memory I'm going to do it."

"And I'm with you!" exclaimed Andy heartily.

The two brothers cast backward glances at the vessel with which they
had had a clash. It was rapidly disappearing in a slight haze that was
arising, and soon Frank thought it would be safe to turn about, sail
with the wind, and take after the mysterious man.

But he did not count on the weather. Soon the wind increased in
violence, and there was a choppy sea.

"I don't like this," remarked Andy, as their small craft pitched and
tossed on the waves. "I don't mean I'm seasick, or anything like that,
but we're getting pretty far out, and with a storm coming on toward
night--"

"That's right," agreed Frank. "We'll have to turn back. It's tough
luck, just as we're on the right track, but it can't be helped. It
wouldn't be right to make mom and dad worry. We'll beat it back for
home."

But the wind came up with such sudden violence, and the sea ran so
high, that the best the boys could do was to run for shelter. In fact
it was only with considerable risk that they made a safe harbor, for
with a rising tide and a cross current their small craft was in a bad
way