leaden frame. Between the door and the window to the left stood an immense bookcase of Renaissance style, on the pediment of which, in letters of gold, was the world "Thibermesnil," and, below it, the proud family device: "Fais ce que veulx" (Do what thou wishest). When the guests had lighted their cigars, Devanne resumed the conversation.
"And remember, Velmont, you have no time to lose; in fact, to-night is the last chance you will have."
"How so?" asked the painter, who appeared to regard the affair as a joke. Devanne was about to reply, when his mother mentioned to him to keep silent, but the excitement of the occasion and a desire to interest his guests urged him to speak.
"Bah!" he murmured. "I can tell it now. It won't do any harm."
The guests drew closer, and he commenced to speak with the satisfied air of a man who has an important announcement to make.
"To-morrow afternoon at four o'clock, Herlock Sholmes, the famous English detective, for whom such a thing as mystery does not exist; Herlock Sholmes, the most remarkable solver of enigmas the world has ever known, that marvelous man who would seem to be the creation of a romantic novelist—Herlock Sholmes will be my guest!"
Immediately, Devanne was the target of numerous eager questions. "Is Herlock Sholmes really coming?" "Is it so serious as that?" "Is Arsène Lupin really in this neighborhood?"
"Arsène Lupin and his band are not far away. Besides the robbery of the Baron Cahorn, he is credited with the thefts at Montigny, Gruchet and Crasville."
"Has he sent you a warning, as he did to Baron Cahorn?"
"No," replied Devanne, "he can't work the same trick twice."
"What then?"
"I will show you."
He rose, and pointing to a small empty space between the two enormous folios on one of the shelves of the bookcase, he said:
"There used to be a book there—a book of the sixteenth century entitled `Chronique de Thibermesnil,' which contained the history of the castle since its construction by Duke Rollo on the site of a former feudal fortress. There were three engraved plates in the book; one of which was a general view of the whole estate; another, the plan of the buildings; and the third—I call your attention to it, particularly—the third was the sketch of a subterranean passage, an entrance to which is outside the first line of ramparts, while the other end of the passage is here, in this very room. Well, that book disappeared a month ago."
"The deuce!" said Velmont, "that looks bad. But it doesn't seem to be a sufficient reason for sending for Herlock Sholmes."
"Certainly, that was not sufficient in itself, but another incident happened that gives the disappearance of the book a special significance. There was another copy of this book in the National Library at Paris, and the two books differed in certain details relating to the subterranean passage; for instance, each of them contained drawings and annotations, not printed, but written in ink and more or less effaced. I knew those facts, and I knew that the exact location of the passage could be determined only by a comparison of the two books. Now, the day after my book disappeared, the book was called for in the National Library by a reader who carried it away, and no one knows how the theft was effected."
The guests uttered many exclamations of surprise.
"Certainly, the affair looks serious," said one.
"Well, the police investigated the matter, and, as usual, discovered no clue whatever."
"They never do, when Arsène Lupin is concerned in it."
"Exactly; and so I decided to ask the assistance of Herlock Sholmes, who replied that he was ready and anxious to enter the lists with Arsène Lupin."
"What glory for Arsène Lupin!" said Velmont. "But if our national thief, as they call him, has no evil designs on your castle, Herlock Sholmes will have his trip in vain."
"There are other things that will interest him, such as the discovery of the subterranean passage."
"But you told us that one end of the passage was outside the ramparts and the other was in this very room!"
"Yes, but in what part of the room? The line which represents the passage on the charts ends here, with a small circle marked with the letters `T.G.,' which no doubt stand for `Tour Guillaume.' But the tower is round, and who can tell the exact spot at which the passage touches the tower?"
Devanne lighted a second cigar and poured himself a glass of Benedictine. His guests pressed him with questions and he was pleased to observe the interest that his remarks had created. The he continued:
"The secret is lost. No one knows it. The legend is to the effect that the former lords of the castle transmitted the secret from father to son on their deathbeds, until Geoffroy, the last of the race, was beheaded during the Revolution in his nineteenth year."
"That is over a century ago. Surely, someone has looked for it since that time?"
"Yes, but they failed to find it. After I purchased the castle, I made a diligent search for it, but without success. You must remember that this tower is surrounded by water and connected with the castle only by a bridge; consequently, the passage must be underneath the old moat. The plan that was in the book in the National Library showed a series of stairs with a total of forty-eight steps, which indicates a depth of more than ten meters. You see, the mystery lies within the walls of this room, and yet I dislike to tear them down."
"Is there nothing to show where it is?"
"Nothing."
"Mon. Devanne, we should turn our attention to the two quotations," suggested Father Gélis.
"Oh!" exclaimed Mon. Devanne, laughing, "our worthy father is fond of reading memoirs and delving into the musty archives of the castle. Everything relating to Thibermesnil interests him greatly. But the quotations that he mentions only serve to complicate the mystery. He has read somewhere that two kings of France have known the key to the puzzle."
"Two kings of France! Who were they?"
"Henry the Fourth and Louis the Sixteenth. And the legend runs like this: On the eve of the battle of Arques, Henry the Fourth spent the night in this castle. At eleven o'clock in the evening, Louise de Tancarville, the prettiest woman in Normandy, was brought into the castle through the subterranean passage by Duke Edgard, who, at the same time, informed the king of the secret passage. Afterward, the king confided the secret to his minister Sully, who, in turn, relates the story in his book, "Royales Economies d'Etat," without making any comment upon it, but linking with it this incomprehensible sentence: `Turn one eye on the bee that shakes, the other eye will lead to God!'"
After a brief silence, Velmont laughed and said:
"Certainly, it doesn't throw a dazzling light upon the subject."
"No; but Father Gélis claims that Sully concealed the key to the mystery in this strange sentence in order to keep the secret from the secretaries to whom he dictated his memoirs."
"That is an ingenious theory," said Velmont.
"Yes, and it may be nothing more; I cannot see that it throws any light on the mysterious riddle."
"And was it also to receive the visit of a lady that
