himself
of the nature of this obstacle, he gently moved the tip of his finger to
and fro over what was certainly the edge of a book.

This proved that his calculations had been correct and that the opening
so accessible on his side, was completely veiled on the other by the
books he had seen packed on the shelves. As these shelves had no other
backing than the wall, he had feared striking a spot not covered by a
book. But he had not undertaken so risky a piece of work without first
noting how nearly the tops of the books approached the line of the shelf
above them, and the consequent unlikelihood of his striking the space
between, at the height he planned the hole. He had even been careful to
assure himself that all the volumes at this exact point stood far enough
forward to afford room behind them for the chips and plaster he
must necessarily push through with his auger, and also--important
consideration--for the free passage of the sounds by which he hoped to
profit.

As he listened for a moment longer, and then stooped to gather up the
debris which had fallen on his own side of the partition, he muttered,
in his old self-congratulatory way:

"If the devil don't interfere in some way best known to himself,
this opportunity I have made for myself of listening to this arrogant
fellow's very heartbeats should give me some clew to his secret. As soon
as I can stand it, I'll spend my evenings at this hole."

But it was days before he could trust himself so far. Meanwhile their
acquaintance ripened, though with no very satisfactory results. The
detective found himself led into telling stories of his early home-life
to keep pace with the man who always had something of moment and solid
interest to impart. This was undesirable, for instead of calling out
a corresponding confidence from Brotherson, it only seemed to make his
conversation more coldly impersonal.

In consequence, Sweetwater suddenly found himself quite well and one
evening, when he was sure that his neighbour was at home, he slid softly
into his closet and laid his ear to the opening he had made there. The
result was unexpected. Mr. Brotherson was pacing the floor, and talking
softly to himself.

At first, the cadence and full music of the tones conveyed nothing to
our far from literary detective. The victim of his secret machinations
was expressing himself in words, words;--that was the point which
counted with him. But as he listened longer and gradual