ckle this Dixwell Hardley myself, and make him give up the papers I'm
sure he has hidden away. He has them, I'm positive."

"Well, he may not have them, but perhaps he knows where they are," said
Tom. "And I'm going to make it my business to watch him and see if I
can find out his secret. I won't let him know I've heard from you. I'll
apply the old saying of giving him plenty of rope, and I'll watch what
happens.

"Now, Mr. Keith, take care of yourself. Mary and I must be getting
back. Try not to worry, and I'll do my best for you," Tom concluded.

Mary added a few words of comfort and encouragement to her uncle, and
then she and Tom took leave of him, flying back to Shopton in the
speedy Air Scout.

"What are you going to do, Tom?" asked Mary, as he left her at her
home, having told Mr. and Mrs. Nestor his part in the visit to Barton
Keith.

"I'm going to start on the submarine voyage tomorrow," was the answer
of the young inventor.

"Do you really believe there is a treasure ship?"

"Well, I've satisfied myself that a ship named the Pandora sunk about
where Hardley says it did, and she had some treasure on board. Whether
it's just the kind he has told me it was I don't know. But I'm going to
find out."

"Then you'll be saying goodbye for a long time," observed Mary, rather
wistfully.

"Oh, it may not be for so very long," and Tom tried to speak
cheerfully. "I'll bring you back some souvenirs from the bottom of the
sea," he added with a laugh.

"Bring me back--yourself!" said Mary in a low voice, and then she
hurried away.

By appointment Tom met Mr. Damon and Mr. Hardley at the submarine dock
the next morning. Everything had been made ready for the start,
postponed from the day before. Mr. Hardley's estimated share of the
expenses had been deposited in a bank, to be paid over later.

"Well, are we really going this time, or are you going to delay again?"
asked the gold seeker, and his voice lacked a pleasant tone.

"Oh, were going this time!" exclaimed Tom. "And I hope everything turns
out the way I want it to," he added meaningly.

"We'll find the treasure on the ship all right, if we can find the
ship," said Mr. Hardley. "That part is your job, Mr. Swift."

"And I'll find her if she's where you say she went down," answered Tom.
"Now then, as soon as Ned comes we'll start."

Ned Newton had been intrusted with some last-moment messages, but he
arrived a little later, and hurried on board the M. N.