"One that you don't happen to represent," laughed Jack, quietly.

"Ah, I much doubt it, though I beg you to pardon me for saying so, Captain Benson."

"Why man alive," grumbled Jack, "are you running away with the notion that you're the only one who ever approached me with a view to finding out how the Pollard boat runs? You claim, to be a spy for some other government, M. Lemaire. Are you such an infant as to think yourself the only spy in the field?"

"You would have to tell me about the others. Name them, or describe them to me," urged the Frenchman. "Then I would know, if they are real agents of any foreign government."

"I would tell you nothing of the sort," muttered Captain Jack. "I am young, perhaps, yet I'm old enough to keep my own secrets."

"Then it is agreed, anyway," hastened on the Frenchman, "that, in three days, you will have ready the plans and descriptions, and that I, after I have looked them over and have found them satisfactory, will hand you ten thousand dollars."

"If you've made any such agreement," laughed Benson, "then you've made it with yourself only. You certainly haven't made it with me."

"Don't you agree, then?" asked M. Lemaire.

"No," said Jack, shortly, turning on his heel.

"Where are you going, Captain?"

"Back to Spruce Beach."

"On foot?"

"Yes, for I know your kind too well to suppose that you'll offer me a ride back."

"Wait!" cried M. Lemaire, persuasively, and Benson, halted, looking at him. "Of course I cannot offer you a lift back to town," continued the Frenchman, smilingly, "for that would be ungallant. But Mlle.

Nadiboff, who had the pleasure of your company out here will, I know, be most delighted at having your company on the return."

"a.s.suredly," added the young Russian woman, with one of those charming smiles that had failed so utterly with the submarine boy. "I shall feel most offended if Captain Benson does penance by walking all the miles back to Spruce Beach."

"I'd be a fool, then, to take that long walk back, when I can ride,"

thought Captain Jack.

So he turned, retracing his steps and bowing to the young woman.

"Yet, before we start," proposed M. Lemaire, anxiously, "let us see, Captain, if we cannot yet come to some arrangement."

"Well?" demanded Jack, for boyish curiosity tempted him to find how far this Frenchman was willing to go.

"Captain Benson," proposed Lemaire, "let us say that the price for what I ask shall be fifteen thousand dollars."

"You're not getting anywhere near my price, M. lemaire," laughed the submarine boy, derisively.

"You are playing with me--laughing at me!" cried the Frenchman, yet he spoke cheerily, for now he began to hope that this American boy might yet be induced to sell himself, body, soul and honor.

"We may as well drop this line of talk," hinted Jack Benson. "You were good enough to offer me a ride back to town, I believe?"

"Yet the price? Let us settle that first," begged the Frenchman.

"Captain Benson, I will make you one more offer--but it must be the last. Listen!"

Yet that word was followed by three or four utterly mysterious words, uttered in a low voice in Arabic.

"Yes," nodded Mlle. Nadiboff, as Jack glanced from one to the other, "but this must be the last offer."

"The last, the only, the highest offer," muttered Gaston, who had recovered from the blow Captain Jack had given him.

"Well, then, Captain Benson, bring me your plans within three days, with all the other data needed for the construction of one of your submarine boats, and I will hand you, in exchange, the sum of twenty thousand dollars. There you are, my good friend! Twenty thousand dollars. Now you are ours, are you not?"

Disgusted, yet crafty, Jack Benson pretended to hesitate.

"You must give me your answer at once," demanded M. Lemaire. "I cannot be played with any longer."

Captain Jack drew himself stiffly erect, looking the Frenchman full in the eyes.

"M. Lemaire, you must have been a spy for a good many years. You have been engaged so long in dishonest transactions that you are unable to understand such a thing as common honesty."

"Do you call it honesty," demanded the Frenchman, with a bitter smile, "to demand more than twenty thousand dollars for such an easily performed service?"

"You idiot!" broke forth Jack, in sudden contempt. He was no longer able even to play with this rascal. "Your offer is just as good as one of a million dollars would be. I wouldn't take either!"

"What! You have been trifling with me?" demanded M. Lemaire, starting forward.

Now the meaning of those few words in Arabic became plain enough. For Mlle. Nadiboff, who had bent over, her hand toying with the sand, suddenly clutched a handful of the fine grains and straightened up, hurling the sand full in Benson's face.

In that same flashing instant Gaston darted behind the young American.

As the half-blinded young captain dodged back, the chauffeur caught him around the neck, dragging him to the ground, while Lemaire sprang a-top of the boy.

Jack fought desperately enough, but the two men rolled him over, struggling to hold his hands. Then--

Click! Snap!

Jack Benson's wrists were handcuffed tightly together.

Now M. Lemaire leaped up, looking down gloatingly at the boy.

"Benson, you young fool," scoffed the Frenchman, "since you refuse to be treated as a friend, you shall know what it is to have us for your enemies. You deem it easy to laugh at us--to call us names! Bah!

You will soon be glad to beg from us! Your hours of misery are now before you--perhaps days of torment that shall end in madness. Defy us? Balk our plans? Pouf? How little you know of the people with whom you have now to dealt."

Then, at a sign from Lemaire, Gaston threw himself upon Benson's legs, swiftly binding the ankles together. This done, Lemaire himself added a gag to Jack's mouth that shut off the last chance of making a sound.

This done, the two men bore Captain Jack to the larger auto, while Mlle. Nadiboff, chuckling softly, covered him completely under robes.

CHAPTER XI

JACK'S FRIENDS DO SOME FAST GUESSING