"

"And you manage to make a cruise of days and days under water?"

"Surely!" smiled their host. "There's nothing to prevent it!"

"That's going some!" declared Jimmie. "But I don't believe you managed to
dig up a lot of gold from the bottom of the ocean!"

"What is there to hinder?" questioned the other.

"Everything!" declared Jimmie. "In the first place there is all the water
about. Then, too, it would be easier to take this instrument into the
regions where gold is usually discovered on land. You could prospect with
it in almost the positive knowledge that you would locate a vein. Digging
then would be easy."

"Yes, but I don't like to dig!" laughed the other. "Perhaps I'm too lazy
to do that sort of thing!"

"There's something queer here that I don't quite get," stated Jimmie.
"Can't you explain a little more in detail?"

"Why, certainly, I'll be glad to elucidate!" was the answer. "You have in
mind the securing of free gold in nuggets and dust. I go about it in
quite another way. My purpose is to recover the minted coins that have
been placed aboard ships. When the ships sink, no diver yet has been able
to reach those in deep water. Therefore, most of the gold that has been
carried to the bottom in sunken vessels is forever lost. I intend to
recover a great deal of it!"

"Then when you know approximately where the vessel was wrecked or sunk,"
put in Ned, "you go to that neighborhood. Your instrument indicates the
presence of gold and you follow its directions until the exact spot is
reached. Then you step out and carry the money aboard your own craft. Is
that the correct explanation?"

"You have it exactly. And I have done pretty well so far!"

"I don't believe it!" declared Jimmie flatly. "The whole thing sounds
mighty fishy--not meaning any disrespect," he added addressing the man
who sat leaning back against a bulkhead.

"But I assure you that what I have said is absolutely true!"

"I'm from Missouri!" stated Jimmie in a tone of doubt.

Their host stepped to a locker which he opened.

"Great Frozen Hot Boxes!" cried Jimmie.

CHAPTER XXI

A MYSTERY EXPLAINED

"Why, boys, look at this!" cried Jimmie, his voice rising to a shriek
then trailing off into a whisper. "Did you ever see the like?"

"Let's see!" put in Frank, crowding forward. "What is it?"

Eagerly the boys gathered around the open compartment. They heard
distinctly the tinkle of coins as Jimmie seized a handful and let t