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.

"B