"we will open this box as quickly as possible.
I suppose there is no key to be found, and, if there were, the
lock is too rusty to work."

With the aid of a file and chisel the box was soon opened. The
satin linings were somewhat water-soaked and discolored, and the
box appeared to be empty, but on opening an inner compartment there
were exposed to view a pair of oddly shaped keys and a blood-stained
handkerchief, the latter firmly knotted as though it had been used
to bandage a wound of some kind.

"Ah!" said the detective, with peculiar emphasis, examining the
handkerchief, which was of fine linen, with the initials "H. M."
embroidered in one corner. "Did Mr. Mainwaring carry a handkerchief
of that style?"

"Yes; he carried that, or one precisely like it, the last day of
his life."

"Very good!" was the only reply, as the detective carefully folded
and pocketed the article with an air that indicated that he wished
to say no more about it. "And these keys, do you recognize them?"

"They were Mr. Mainwaring's private keys to his library and the
southern hall."

"The ones the valet said were missing?"

"The same."

Mr. Merrick, after studying them curiously for a moment, consigned
them to his pocket also, and then began a careful inspection of the
interior of the box. Scott watched him in silence, thinking
meanwhile of the old document which he had found hidden away in its
depths, and inwardly rejoicing that it had not been left to be
discovered by the detective. Nothing in Mr. Merrick's manner or
expression betrayed the nature of his thoughts, and, so long as he
chose to remain silent, Scott refrained from questioning him.

At length he closed the box, saying, indifferently, "Well, I don't
know as there is any reason why I should detain you any longer, Mr.
Scott. We have satisfied ourselves as to the contents of the box,
and you have identified the articles. For the present, however, I
would prefer that you say nothing of this."

"Certainly, Mr. Merrick. The discovery, whatever its import, is
your secret, and I shall make no mention of it whatever."

"I don't know that it is of any special importance," said the
detective, carelessly, as they prepared to descend the stairs; "but
it only confirms the opinion that I have had all along."

"Don't you think that this tends to show that the murder and robbery
were connected, notwithstanding Mr. Whitney's theories to the
contrary?" Scott inquired, as t