Poole paused a moment, huskily. He arose and took down a decanter and glasses.

He filled and offered them to his visitors. They sipped the wine. He took a copious draught and then went on:

“Somewhat curiously, the Caribs did not come out to our boat to attack us. If they had we must have yielded easily.

“But we soon learned the reason why. They were treasure-mad. With our picks and shovels they had dug up the gold and were fighting over it like wolves.

“As darkness began to shut down the sea began to experience a strange motion. A dull, cannon-like roar came out of the west. Then we witnessed a terrible phenomenon.

“The waters rose like a mighty flood over the isle. At least that was the way it looked. But instead it was the isle which sank into the sea.”

Frank and Wade each drew a deep breath.

They had been intensely interested.

“Then,” continued Poole, “we had hard work to save the ship, but we made out to live through the vortex, and having fair weather worked the ship into the port of Havana.

“Here we sold her and returned to Paris. I separated from my companions. Monte Carlo drew me into its grip once more, and one night the devil aided me and I broke the bank.

“My first fate was to succumb to the treasure fever. I bought this yacht and fitted it out with a view to making 17a fighting vessel of it. This time I was bound to have means of defense in case of attack.

“My men are picked and trusty. They are all bound to me by the most powerful of oaths. I have every sort of diving apparatus aboard. In this manner I have hoped to recover the treasure. This is my story.”

Neither Frank nor Wade spoke. There was silence for a moment. Then Poole said, in a metallic voice:

“If you have a submarine boat it will be of more service to me than to you. How will you trade it for this yacht? Name your price!”

Frank met the other’s gaze steadily, and replied:

“I do not care to exchange.”

Poole’s face grew livid.

His hand instinctively went to his belt. He said:

“Oh, I can see your game. You will easily recover the treasure yourself of which I have told you. But I may as well tell you now that game will not work. You cannot leave this cabin alive unless you come to terms!”

It was a thrilling moment.

Wade’s face paled.

But Frank was as cool as an icicle.

“That is a strong statement,” he said. “Only a pirate would make it.”

“As you please,” said Poole, carelessly. “I claim the treasure, and it shall be mine!”

“For all of me, you can claim it and recover it,” said Frank. “We are not hunting for treasure.”

It was Poole’s turn now to look utter astonishment.

He sank back in his chair and looked cunningly at his visitors.

“Where are you bound?”

“To the Yucatan Channel,” replied Frank.

“On what errand?”

“A purely scientific one. My friend here, Mr. Wade, is a member of the American Scientific Society and claims that at one time an isthmus existed between the points of Cape San Antonio and Cape Catoche. To prove the matter we propose to explore the deep sea in that vicinity.”

Poole drew a deep breath.

His eyes glittered.

“Mona was upon that parallel,” he said. “You will be sure to locate the treasure that belongs to me; I claim it by right of prior discovery. Of this I warn you!”

“Claim it, and be hanged!” said Wade, with disgust. “Come, Frank, let us go back.”

Both men arose.

But Poole drew a brace of pistols and placed his back against the cabin door. He looked ugly.

18“You shall not leave here until you have given me your oath,” he said.

“You will obstruct us at your peril,” said Frank, very quietly.

“I seem to have the best of the situation just now,” said the villain, showing his white teeth.

“What sort of an oath do you require us to give?” asked Wade.

“You must swear that you will not touch the sunken treasure of Mona,” said the villain, intensely. “You look like men of honor. If you give me your word, you will be likely to keep it.”

“We will give our word,” replied the scientist. “Eh, Frank?”

“Certainly,” replied the young inventor.

Poole studied their faces a moment closely. Then the lines of his face relaxed.

“You will pardon the trouble I have put you to, gentlemen,” he said, “but I am gold-mad. I must have the treasure! I cannot be balked in my purpose!”

“Well,” said Wade, “we have agreed to your terms.”

The villain smiled.

“There are other things,” he said.

Frank’s eyes flashed. He drew his lithe form up.

Wade looked disappointed and not a little alarmed that his temporizing had not been a better success.

Poole fixed his keen gaze upon the two men and continued:

“You have the power to visit the depths of the sea. If Mona is sunk too deep our diving apparatus must fail. Since you will not trade or sell your boat, I must charter it for the purpose of bringing up the gold. I will pay you well for the service—yes, I will give you a fifth of the treasure. Come now, is not that fair?”

For a moment Frank Reade, Jr., was so overwhelmed with scorn that he could not speak. When he did recover his voice it was metallic and raspy.

“My friend,” he said, “you labor under a wrong impression. We are not fools; neither are we to be cajoled or bullied. If you had come to me in an honorable, open manner I would not have refused the favor, but as it stands, I would not grant it to you for any consideration. We are going back to our boat. Be so kind as to unbar that door.”

In spite of his pretended advantage the villain quailed before Frank’s eagle gaze and commanding manner.

He moved uneasily, then took up a whining tone:

“Now, come, my friend, don’t be unreasonable. I didn’t mean those threats. You shall not be sorry.”

19Frank took a step forward. The fellow raised one of his pistols. Quick as lightning Frank grabbed his wrist and then with a downright blow of his other hand, dashed the other pistol from his grip. At the same moment he drew back and hurled the villain from the door. It was done in the twinkling of an eye.

Poole himself was astounded at the ease with which Frank accomplished this. His murderous spirit at once flamed up.

“Curse you!” he hissed. “I’ll have your life for that!”

He wrenched his hand free and raised the pistol left him. But like a flash Wade brought his fist down upon the villain’s hand and dashed the weapon to the floor.

Then the scientist proved that he could fight as well as solve geographical problems. With a leap like a panther he had clutched Poole’s windpipe.

Frank came to his aid, and together they bore the villain to the cabin floor. He could make no outcry, and, furious though he was, could not act.

Could he have made an outcry, or a signal of alarm, in less time than it takes to tell it he would have had assistance which would have turned the tables.

But Frank and Wade were already determined upon their plan of action.

They knew well that if they allowed their prisoner to make an outcry their fate would be sealed. So while Wade held the helpless villain by the throat Frank forced a gag into his mouth.

Then he hastily tied his arms and legs with some cord which he found in the cabin. Thus placed hors-de-combat, the wretch was left.

Frank and Wade very coolly stepped out of the cabin and closed the door behind them. A moment later they were on deck.

Two armed men of the crew stood at the gangway, but neither Frank nor Wade affected to notice them, and descended to the boat.

“Row us back!” said Frank, authoritatively to the oarsmen.

“Ay, ay, sir!” was the reply, and they bent to their work. A few minutes later Frank and Wade were on board the Sea Diver.

They had barely gained the deck when an uproar was heard on board the schooner.

“They have found him!” exclaimed Wade. “What shall we do, Frank?”

“Put on all speed, Barney!” cried Frank. “Steer due west!”

“All roight, sor.”

20The submarine boat shot forward. But just at that moment a jet of flame shot from the side of the schooner, and a heavy boom smote upon the air.

A cannonball just grazed the stern of the Sea Diver.

“Egad!” cried Wade. “That won’t do, Frank! If that had struck us fair we would have gone to the bottom to stay!”

“Right!” cried Frank. “Douse the lights, Barney. Veer to the south.”

All was done in the twinkling of an eye. The Diver was in instant darkness and was running away like a flash on another course.

The piratical schooner kept up a random fire in an opposite direction. But the game had slipped them.

“Hurrah!” cried Wade, jubilantly, “didn’t we give them a good slip! Serves the rascals right!”

“Aye,” replied Frank; “he was more than a rogue, that fellow!”

“We may see him again.”

“If we do, we will not place ourselves in the lion’s mouth again.”

“You are right.”

It was true that their destination was the same—that is, the Yucatan Channel, but forewarned is forearmed, and the voyagers were not to be deceived in the character of Hardy Poole now.

“Begorra, it’s bad luck to the omadhouns,” cried Barney. “Av we only had a dynamite gun wid us now, we’d be able to settle their account foriver!”