“Nonsense!” he replied.  “I was inclined to think so at first; your fine acting and man’s conceit, I reckon.  But my conceit has been punctured, and you’ve slipped a bit in your acting; therefore, to descend to the extremely common-place, the jig is up.”

“And the next lead is yours!” she laughed back.

“That is precisely why I asked you the game—­so I could make an intelligible lead.”

“Ask Mrs. Clephane!” she suggested.

“I’ll do it,” said he—­and bowed himself out.

“Do it?  Of course, you’ll do it,” Madeline Spencer gritted, as the door closed behind him.  “I’ve no chance, it seems, against a red-haired woman.  The other one also had red hair.”  She seized a vase from the table at her hand, and hurled it across the room.  It crushed in fragments against the wall.  “Damn Mrs. Clephane!” she said softly.

XXI

THE KEY-WORD

Promptly at ten o’clock Marston walked into Carpenter’s office and sent in his card.

It found Carpenter pacing up and down, and frowning at a paper spread open on his desk.  At the messenger’s apologetically discreet cough, he glanced around and took the extended card.

“Show him in!” he snapped, and swept the paper from the desk and into a drawer....  “Good-morning, sir!” as Marston bowed on the threshold; then, without any preliminaries:  “What success?”

“I have the French code-book,” Marston replied.

“With you?”

Marston drew out the slender book.  “It embraces all their codes, I believe,” he remarked.

“H-u-m!” said Carpenter thoughtfully, retrieving the paper he had just swept into the drawer.  “How are we to work it, Mr. Marston?”

“As allies,” Marston replied.  “I’m perfectly willing to let you have the book and everything in it, if you will let me have a copy of the letter.  I’m confident that the key-word is here; I’m equally confident that the letter does not involve, either directly or indirectly, the United States.  I understand that the letter is in the cipher of the Blocked-Out Square; in this book there are two pages and more of key-words to this Square, the last dozen or so of which are added in writing.  If the letter is in that cipher, we should have no particular difficulty in finding the key-word.  I would suggest, however, that we first try the last word on the list—­maybe we won’t have to go any farther.”

“Very well,” said Carpenter, briskly.

The advantage was all with him.  If Marston thought the letter was only a line and that he could remember the letters used, he was in for a shock.  No man living could remember twenty spilled alphabets; and if he attempted to make a copy it could easily be prevented.  The Fifth Secretary spread the paper on the table.

“Here is a copy of the cipher letter in question—­we had it made large for convenience,” he explained.  “The original is in the safe; you’ll wish to compare it with the copy, so we’ll have it here.”