"Mr. Hardley," began Tom calmly, as he took a seat in the main cabin, "when we started this search I told you that hunting for something on the bottom of the sea was not like locating a building at the intersection of two streets."

"Well, what if you did?" snapped the gold-seeker. "You're supposed to do the navigating, not I! You said if I gave you the latitude and longitude, down to seconds, as well as degrees and minutes, which I have done, that you could bring your submarine to that exact point."

"I said that, and I have done it," declared Tom. "When we computed our position the other day we were at the exact location you gave me as being the spot where the Pandora foundered."

"Then why isn't she here?" demanded the unpleasant adventurer. "We went down to the bottom at the exact spot, and we've been cruising around it ever since, but there isn't a sign of the wreck. Why is it?"

"I'm trying to explain," replied Tom, endeavoring to keep his temper. "As I said, finding a place on the open sea is not like going to the intersection of two streets. There everything is in plain sight. But here our vision is limited, even with my big searchlight. And being a few feet out of the way, as one is bound to be in making nautical calculations, makes a lot of difference. We may have been close to the wreck, but may have missed it by a few yards."

"Then what's to be done?" asked Mr. Hardley.

"Keep on searching," Tom answered. "We have plenty of food and supplies. I came out equipped for a long voyage, and I'm not discouraged yet. Another thing. The ship may have moved on several fathoms, or even a mile or two, after her last position was taken before she went down. In that case she'd be all the harder to find. And even granting that she sank where you think she did, the ocean currents since then may have shifted her. Or she may be covered by sand."

"Covered by sand!" exclaimed the gold-seeker.

"Yes," replied Tom. "The bottom of the ocean is always changing and shifting. Storms produce changes in currents, and currents wash the sand on the bottom in different directions. So that a wreck which may have been exposed at one time may be covered a day or so later. We'll have to keep on searching. I'm not ready to give up."

"Maybe not. But I am!" snapped out Mr. Hardley.

"What do you mean?" asked the young inventor.

"Just what I said," was the quick answer. "I'm not going to stay down here, cruising about without knowing where I'm going. It looks to me as if you were hunting for a needle in a haystack."

"That's just about what we are doing," and Tom tried to speak good-naturedly.

"Then do you know what I think?" the gold-seeker fairly shot forth.

"Not exactly," Tom replied.

"I think that you don't understand your business, Swift!" was the instant retort. "You pretend to be a navigator, or have men who are, and yet when I give you simple and explicit directions for finding a sunken wreck you can't do it, and you cruise all around looking for it like a dog that has lost the scent! You don't know your business, in my estimation!"

"Well, you are entitled to your opinion, of course," agreed Tom, and both Mr. Damon and Ned were surprised to see him so calm. "I admit we haven't found the wreck, and may not, for some time."

"Then why don't you admit you're incompetent?" cried Mr. Hardley.

"I don't see why I should," said Tom, still keeping calm. "But since you feel that way about it, I think the best thing for us to do is to separate."

"What do you mean?" stormed the other.

"I mean that I will set you ashore at the nearest place, and that all arrangements between us are at an end."

"All right then! Do it! Do it!" cried Mr. Hardley, shaking his fist, but at no one in particular. "I'm through with you! But this is your own decision. You broke the contract--I didn't, and I'll not pay a cent toward the expenses of this trip, Swift! Mark my words! I won't pay a cent! I'll claim the money I deposited in the bank, and I won't pay a cent!"

"I'm not asking you to!" returned Tom. with a smile that showed how he had himself in command. "You put up a bond, secured by a deposit, to insure your share of the expenses--yours and Mr. Damon's. Very well, we'll consider that bond canceled. I won't charge you a cent for this trip. But, mark this, Hardley: What I find from now on, is my own! You don't share in it!"

"You mean that--"

"I mean that if I discover the wreck of the Pandora and take the gold from her, that it is all my own. I will share it with Mr. Damon, provided he remains with me--"

"Bless my silk hat, Tom, of course I'll stay with you!" broke in the eccentric man.

"But you don't share with me," went on the young inventor, looking sternly at the gold-seeker. "What I find is my own!"

"All right--have it that way!" snapped the adventurer. "Set me ashore as soon as you can--the sooner the better. I'm sick of the way you do business!"

"Nothing like being honest!" murmured Ned. But, as a matter of fact, he was glad the separation had come. There had been a strain ever since Hardley came aboard. Mr. Damon, too, looked relieved, though a trifle worried. He had considerable at stake, and he stood to lose the money he had invested with Dixwell Hardley.

"This is final," announced Tom. "If we separate we separate for good, and I'm on my own. And I warn you I'll do my best to discover that wreck, and I'll keep what I find."

"Much good may it do you!" sneered the other. "Perhaps two can play that game."

No one paid much attention to his words then, but later they were recalled with significance.

"Get ready to go up!" Tom called the order to the engine room.

"Where are you going to land me?" asked Mr. Hardley. "I have a right to know that?"

"Yes," conceded Tom, "you have. I'll tell you in a moment."

He consulted a chart, made a few calculations and then spoke.

"I shall land you at St. Thomas," answered the young inventor. "I do not wish to bring my submarine to a place that is too public, as too many questions may be asked. From St. Thomas you can easily reach Porto Rico, and from there you can go anywhere you wish."

"Very well," murmured the malcontent. "But I don't consider that I owe you a cent, and I'm not going to pay you."

"I wouldn't take your money," Tom answered. "And don't forget what I said--that what I find is my own."

The other answered nothing. Nor from then on did he hold much conversation with Tom or any others in the party. He kept to himself, and a day later he was landed, at night, at a dock, and if he said "good-bye" or wished Tom and his friends a safe voyage, they did not hear him.

They were steaming along on the surface the next day, and at noon the submarine suddenly halted.

"What's on now, Tom?" asked Ned, as he saw his chum prepare to go up on deck with some of the craft's officers.

"We're going to 'shoot the sun' again," was the answer. "I want to make sure that we were right in our former calculations as to the position of the Pandora. The least error would throw us off."

Using the sextant and other apparatus, some of which Tom had invented himself, the exact position of the submarine was calculated. As the last figure was set down and compared with their previous location, one of the men who had been doing the computing gave an exclamation.

"What's the matter?" asked Tom.

"Look!" was the answer, and he pointed to the paper. "There's where a mistake was made before. We were at least two miles off our course

"You don't say so!" exclaimed Tom, and, taking the sheet, he went rapidly over the results.