“It must seem strange to be a spy,” murmured the young woman.  “It must give one a strange feeling.”

“Yes, and a mighty mean feeling,” agreed Jack, coolly.

As he spoke he raised his eyes carelessly to her face.  He did not make the glance so significant as to betray his real thoughts.

Mlle. Nadiboff did not flinch nor change color under that brief scrutiny.  Instead, she appeared to be almost lost in thought as she walked along.

Suddenly she clutched at the young captain’s arm.

“I wonder if you would do something very great, to please me?” she murmured, questioningly.

“I’d certainly like to have you try me,” responded Jack Benson, in an equally low tone.  He spoke the truth, too, for he believed that this charming but dangerous companion was scheming some sudden move in her plans as, a spy.  He wanted to find out what that move would be.  Above all, if it were possible, he wanted to get knowledge of which foreign country she represented.

“Won’t you contrive to drive alone with me in my car, when we reach it?” she whispered, coaxingly.

“And leave your chauffeur behind, also?” asked Jack, smiling.

“That will not be necessary.  I do not mind him.  But I have much that I wish to say to you, my Captain.  As for your friend—­pardon me, but he is dull, and—­”

“Quiet, I think you mean, Mademoiselle,” interposed Jack.  “Hal’s worst enemy, if he had one, would hardly call him dull.”

“Anyway, my Captain,” murmured the young woman, “he does not interest me, and I do want a few words with you.”

“This charming young spy,” muttered Benson quickly, to himself, “is beginning to feel that I’m not enough interested to be coaxed away from my duty by flatteries.  I take it she means to show her real hand, and try to play it in earnest.  If that’s the case, I want to know what she is going to say.”

Aloud he replied: 

“It will be easy enough to send my friend away with the others, Mademoiselle.  When we reach the automobile all I shall have to do will be to look straight at him.”

“Ah!  You have a code of signals—­you two?” Mlle. Nadiboff laughed, delightedly.

“A code?” repeated Jack.  “No; we have never needed one.  But my chum is an unusually bright and quick young man.”

CHAPTER IX

“Dog, who is your master?”

Seeing Jack and the young Russian woman so interested in their talk, the others had gradually strolled away from them.

Hennessy had already succeeded in securing an invitation to return to Spruce Beach in Mr. Farnum’s hired auto.

Hal Hastings presently turned, as though to step over to Mlle. Nadiboff’s car, but he caught a swift look from Jack, and turned back.  Hal had not yet heard of the grave suspicion against the young woman, and could not guess what this move of his chum’s meant.  Hastings, however, was swift to take the hint.