been seeking for many weeks. During the night, he found time to solve
the problem, collect his men, and rob the castle. I shall be quite as
expeditious."

He walked from end to end of the room, in deep thought, then sat down,
crossed his long legs and closed his eyes.

Devanne waited, quite embarrassed. Thought he: "Is the man asleep? Or is
he only meditating?" However, he left the room to give some orders, and
when he returned he found the detective on his knees scrutinizing the
carpet at the foot of the stairs in the gallery.

"What is it?" he enquired.

"Look.... there.... spots from a candle."

"You are right--and quite fresh."

"And you will also find them at the top of the stairs, and around
the cabinet that Arsene Lupin broke into, and from which he took the
bibelots that he afterward placed in this armchair."

"What do you conclude from that?"

"Nothing. These facts would doubtless explain the cause for the
restitution, but that is a side issue that I cannot wait to investigate.
The main question is the secret passage. First, tell me, is there a
chapel some two or three hundred metres from the castle?"

"Yes, a ruined chapel, containing the tomb of Duke Rollo."

"Tell your chauffer to wait for us near that chapel."

"My chauffer hasn't returned. If he had, they would have informed me. Do
you think the secret passage runs to the chapel? What reason have--"

"I would ask you, monsieur," interrupted the detective, "to furnish me
with a ladder and a lantern."

"What! do you require a ladder and a lantern?"

"Certainly, or I shouldn't have asked for them."

Devanne, somewhat disconcerted by this crude logic, rang the bell. The
two articles were given with the sternness and precision of military
commands.

"Place the ladder against the bookcase, to the left of the word
Thibermesnil."

Devanne placed the ladder as directed, and the Englishman continued:

"More to the left.... to the right....There!....Now, climb up.... All the
letters are in relief, aren't they?"

"Yes."

"First, turn the letter I one way or the other."

"Which one? There are two of them."

"The first one."

Devanne took hold of the letter, and exclaimed:

"Ah! yes, it turns toward the right. Who told you that?"

Sherlock Holmes did not reply to the question, but continued his
directions:

"Now, take the letter B. Move it back and forth as you would a bolt."

Devanne did so, and, to his great surprise, it produced a