, Bill, you're off watch to-morrow and I want you
to do something for me."

"Anything you say."

"This may involve danger."

"Great Scott, you talk like Sherlock Holmes or a dime novel. What's up?"

"I've got the man who stole those diamonds."

"What!"

"Don't talk so loud. I mean what I say. Listen."

And Jack related everything that had occurred.

"Now, what I want you to do is to watch Prof. Dusenberry, as he calls
himself, to-morrow when we get into the harbor. His is an inside
stateroom so that he can't throw it out of a porthole from there. He'll
most likely go to one at the end of a passage."

"Yes, and then what?"

"I'd do it myself but the old fox suspects me, I half fancy, and if he
saw me in the vicinity he'd change his plans. You'd better take two of
your huskiest firemen with you, Billy. He's an ugly customer, I fancy,
and might put up a bad fight."

"U-m-m-m, some job," mused Billy. "Why don't you put the whole thing up
to the captain?"

"It would do no good the way things are now, and he might get wind of it
and hide the jewels so that they couldn't be found. Anyhow, we've no
proof against him till he is actually caught throwing the jewels out in
that life-preserver to his confederates in the motor-boat."

"I see, you want to catch him red-handed, but what about those cipher
radios?"

"There's no way of proving that I read the cipher right," said Jack.
"Our only way is to do as I suggested."

"I hear that Rosenstein has offered a big reward for the recovery of the
diamonds," said Billy. "He's up and about again, you know."

"Well, Billy, I think he'll have his diamonds back by to-morrow noon if
we follow out my plan."

And so it was arranged. The next morning Jack received a message from
Southampton:

"All ready. Does our man suspect anything?"

This was Jack's answer:

"Not so far as I know. Have a plan to catch him red-handed. You watch
the motor-boat."

Saluted by the whistles of a hundred water craft, the _Columbia_ made
stately progress into Southampton harbor. As her leviathan bulk moved
majestically along under reduced speed, her whistles blowing and her
flag dipping in acknowledgment of the greeting, Jack with a beating
heart, stood on the upper deck watching earnestly for developments.

He knew that Billy and the two firemen he had selected to help him, on
what might prove a dangerous job, were below watching Prof. Dusenberry.
They all wore stewards' uniforms so that