That it might be Madeline Spencer, now that her presence in Washington was declared, Harleston thought possible.  “Slender, twenty-eight, walks as though the ground were hers,” the telephone operator had said.  He would get the photograph from Carpenter and let Miss Williams see it.  If she recognized it as Spencer, much would be explained.

He stopped a moment at the Club, then went on to the State Department.  As he turned the corner near the Secretary’s private elevator, the Secretary himself was on the point of embarking and he waited.

“You want to see me?” he asked.

“Just a moment, Mr. Secretary, since you’re here,” Harleston responded.  “I came particularly to see Carpenter.  There has been a plenty doing in that matter, but nothing worthy of report to you—­except one thing.  Madeline Spencer is in town.”

“The devil she is!” exclaimed the Secretary.

“And as beautiful, as fascinating, as sinuous, and as young as ever.”

“She must be a vision.”

“She is—­and an extraordinarily dangerous vision.”

“Only to you impressible chaps!” the Secretary confided.  “She is not dangerous to me, be she ever so beautiful, and fascinating, and sinuous, and young.  When will you present me?”

“When do you suggest?” Harleston asked.

“Tomorrow, at four?”

“If I can get the lady, certainly.”

“Later she’ll get me, you think!” the Secretary laughed.

“If she is so minded she’ll get you, I have not the least doubt,” Harleston shrugged.

“Then here is where you have your doubt resolved into moonshine.”

“Very well; it won’t be the first time I’ve had the pleasure of seeing moonshine.  I’ll try to make the appointment for tomorrow at four.”

“Self-opinionated old mountebank,” Harleston thought, as he went down the corridor to Carpenter’s office.  “I shall enjoy watching Spencer make all kinds of an ass of him.  ’You impressible chaps!—­not dangerous to me!’ Oh, Lord, the patronizing bumptiousness of the man!...  Have you anything for me, Carpenter?” he asked, as he entered the latter’s office.

The Fifth Assistant was sitting with his feet on his desk, a cigar in his mouth, his gaze fixed on vacancy.

“Damn your old cipher, Harleston!” he remarked, coming out of his abstraction.  “It’s bothered me more than anything I’ve tackled for years.  I can’t make head nor tail of it.  Its very simplicity—­or seeming simplicity—­is what’s tantalizing.  It’s in French.  Of so much I feel sure, though I’ve little more than intuition to back it.  As you know, this Vigenerie, or Blocked-Out Square, cipher is particularly difficult.  I’ve tried every word and phrase that’s ever been used or discovered.  We have a complete record of them.  None fit this case.  Can you give me anything additional that will be suggestive?”

“Here’s what I’ve brought,” Harleston replied—­and related, so far as they seemed pertinent, the incidents of the previous afternoon and evening.