For a s.p.a.ce she looked at him with cold repellence, eyes black as night.

Then her eyes narrowed and she laughed, a mirthlessly sarcastic laugh, so low that Harleston barely heard it.

"Is red hair then prettier than black, Mr. Harleston?" she asked mockingly; "or is Mrs. Clephane's character whiter than mine?"

"That is not worthy of you, Madeline," Harleston reproved. "You're a good sport; hitherto you've taken the count, as well as given it, without the flutter of an eyelash--and over far more serious matters than your humble servant, who hasn't anything to give him value."

Again the sarcastic laugh. She knew he was playing the game, two games indeed, the diplomatic and his own. He had never forgot himself nor regarded her for one little instant.

"As a lecturer on morals, Mr. Harleston, you are a wonder," she mocked; "you have almost succeeded--nay quite, shall I say--in convincing yourself. And when you--a man--do that, what is to be expected of a woman--who is alone in the world? So I must accept your argument, and your conclusions, and be content with my duty--and"--with a sudden ravishing smile--"if I best you, Guy, you will have only yourself to blame. I won't send Mrs. Clephane a present, nor will I wish you joy of her, nor her of you; but _you_ won't look for it, and _she_ would think it somewhat presumptuous in me to a.s.sume to know you. These red-headed women are the very devil, Guy, after they've got you landed--also before, but in a different way."

"What's your game, Madeline?" he smiled. It had pleased her suddenly to veer around and resume the play; and far be it from him to balk her.

"I'll admit you have me guessing."

"I thought you believed me, Guy. My game was you--and I've lost."

"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. "d.a.m.n 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."

He gave the necessary order; when the letter was brought he pa.s.sed it to Marston.

"I'll read the copy, if you'll hold the original," he said; and proceeded to call off the letters with amazing rapidity. "Correct, isn't it?" as he ended.

"Yes!" said Marston returning the original to Carpenter. He wanted in every way to disarm suspicion; moreover, a copy could be made more readily from a large typewritten edition than from the small, written original. "Now for the code-book and the last key-word--_a l'aube du jour_, I think it is ... yes, _a l'aube du jour_, it is," and he handed the book across. "Shall we try it first, Mr. Carpenter?"

"By all means," said Carpenter. "Shall I set it down, or will you?"

One would never have imagined from his expression or his intonation that he had already tried _a l'aube du jour_ for the key-word and failed; nor that why he had failed he now knew. The book was right as to the word, and the slip that Harleston had taken from Crenshaw's pocket-book confirmed it. _a l'aube du jour_ was not the key-word but the key-word was constructed from it by some arbitrary rule; and that rule was susceptible of solution. After he was free of this fellow Marston, he would solve the problem quickly enough. It was as sure as tomorrow. The prescience was come.

"About twenty letters should be enough for experiment?" he suggested, taking up a test card.

When he had written the key-word and the letters under it, he, scarcely without reference to the Blocked-Out Square, wrote the translation.

Marston did the same, very much slower.

"It doesn't fit!" Marston announced. "You can't make anything out of AGELUMTONZN, and so forth."

"I can't!" Carpenter smiled--and waited. Would Marston suggest the transposed or elided word?

"I'm disappointed," Marston confessed, "I thought sure we had it. Let's try the next key-word in the book."

They tried it, and the next, and all the rest. None of them translated the letter.

It took more than an hour; at the end, as a full measure of good faith and because it was of no further use to him--he having preserved a copy--Marston insisted that Carpenter retain the original of the French code-book and have a copy made, after which the book could be returned to him at the Chateau. During this hour and more his hand was in and out in his side coat-pocket. When he left the room there went with him, in that pocket, a copy of the original letter--roughly made by the sense of touch alone, yet none the less a copy and sufficiently distinct to be decipherable. For years Marston had practised writing in the dark and under all sorts of handicaps. In his pocket, a number of small slips of paper and a pencil were concealed. He would write a line, then take his hand from his pocket; after a time he would shift the page of paper, write another line, and then another, and so on until the copy was made.

And all the while he was so frankly communicative, with apparently not the slightest intent to obtaining a copy--even tearing up the paper on which were the various trial translations--that he completely deceived Carpenter. When he left, the latter went with him to the elevator and bowed him down.

"I don't quite understand their game," Carpenter chuckled, as he turned away, "but it's no matter. I took all the tricks this morning and still have a few trumps left. I thought he certainly would try for a copy of the letter, but he didn't even attempt it. He may have committed it to memory, but I'll chance it."

Returning to his office he gave the code-book another careful inspection and confirmed his impression as to its being authentic. Then he laid it aside, and took up the letter and _a l'aube du jour_!

First he tried it in reverse position: _ruoj ud ebua'l a_. The translation was gibberish. Then he wrote the first and last letters, the second and next to last, the third and the third from last, and so on.

The result, too, was gibberish. Next he dropped the first word, 'a' and tried the rest--still gibberish. He dropped also the 'l'--still gibberish. Then, in turn, the 'a' of the third word the 'd' of the fourth, the 'j' of the last word--all gibberish. Next he wrote the key-word entire but transposed the 'a' from the first letter to the last--still gibberish. He began with the _aube_--still gibberish.

"d.a.m.n!" said he.

He was persuaded that the key-word was in the sentence before him; the code-book, Crenshaw's slip of paper, and his own hunch were convincing, yet the combination was slow in coming.

_Du jour a l'aube_ was the next arrangement. He wrote it under the printed words and began to apply the Square.

The D and the A yielded A; the U and the B yielded V; the J and the C yielded E; the O and the D yielded R; the U and the E yielded T; the R and the F yielded I.