ir
of a man who has an important announcement to make.

"To-morrow afternoon at four o'clock, Sherlock Holmes, the famous
English detective, for whom such a thing as mystery does not exist;
Sherlock Holmes, 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--Sherlock Holmes will be my guest!"

Immediately, Devanne was the target of numerous eager questions. "Is
Sherlock Holmes really coming?" "Is it so serious as that?" "Is Arsene
Lupin really in this neighborhood?"

"Arsene 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 Sherlock Holmes."

"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 thef