Nadiboff's partner could rejoin her, M. Lemaire appeared around a palm at Mlle. Nadiboff's back as naturally as though he had not been playing the eavesdropper.

"Have a care, Sara," he whispered, mockingly, "or you will fail in making a fool of that young fellow!"

Half way through the next dance Jack and his friends remained in their seats. Then Hal, stifling a yawn behind his hand, remarked:

"I've a notion that I shall be asleep in a few minutes. Late hours, except on duty, don't jibe with our line of work."

"They don't," admitted Captain Jack, rising.

"Good, boys!" nodded Mr. Farnum, approvingly, as he also rose. "The more rest you have the keener your wits will be for your work."

So they left the ballroom, observed by but few.

Five minutes later Mlle. Nadiboff sat surrounded by three men, with whom she was chatting gayly. M. Lemaire approached her. She greeted him so pointedly that the other three men soon fell away.

"I can hardly congratulate you, Sara," hissed M. Lemaire, speaking in
French.

"You think I have not made young Benson attentive enough to my whims?" the young woman asked, plaintively.

"Attentive?" sneered M. Lemaire. "Do you know where he is now?"

"No," admitted Mlle. Nadiboff.

"He has gone away upstairs with his friends, that they may all be prepared for an early and full day's work."

"You are jesting with me," protested Mlle. Nadiboff, indignantly.

"Take my arm, then, if you will," requested M. Lemaire. "We will stroll about, and we shall see if your eyes are keen enough to discover your young submarine captain."

The young woman defiantly accepted the challenge. By the time that they had strolled around the ballroom scarlet spots glowed in her cheeks. In either eye a tear of anger glistened behind the lash.

"Are you satisfied?" murmured M. Lemaire, in a low voice.

"I fear that I shall have to teach the young cub a lesson or two in the art of showing devotion to a woman's wishes," Mlle. Nadiboff answered, tremulously.

"Shall we walk in the grounds?"

"I beg you to take me out into the air," replied the young woman.

"Yes, it will be better," whispered her companion, cruelly. "Your face is aflame. You will attract too much attention here, and too much curiosity. The American naval officers have sharp eyes—sometimes!"

Procuring his companion's wrap at the coatroom, and throwing a light topcoat about himself, M. Lemaire led the way to a distant settee from which they could look out over the star lit waters beyond the beach. The man had an especial reason for choosing this seat. From that place they could quickly catch sight of anyone who came near enough to overhear.

"Sara," began M. Lemaire, less brutally than his companion had expected him to speak, "for once I fear that you are going to fail utterly."

"Then you do, not know me," she replied, with spirit. "I shall win!
I shall have Captain Jack Benson carrying my fan and craving my smile.
And that shall be quickly, too!"

"If you do not succeed, Sara," retorted the man, "then sterner measures will have to be tried. This youthful Benson may even have to lose his life in the attempt that must be made, at all hazards, to wrest from him a set of drawings of the boat he commands, and a description of all her working parts, and all the secrets of managing the boat!"

"If he could hear you, he would be charmed with the outlook," muttered the young woman, shrugging her shoulders.

"Sara, do you comprehend the situation altogether? The Pollard type of submarine boat is now the most formidable and dangerous in the world—and only the United States Government can buy boats from the makers! Any country in the world that goes to war with the United States must be beaten unless that country knows how to provide itself with submarine boats equal to those of the Pollard make. You may be sure that, at this moment, Spruce Beach is overrun with spies representing every great government in the world. The first country to buy, steal, coax or drag out the Pollard secrets wins! You know the master we serve, Sara, among the governments. We must be the spies who win—even though all the Pollard crew have to be destroyed!"