d to expect. Nor is it, Mr. Roberts.
But let us hope you will pardon this subterfuge when you learn that it
was resorted to for the sole purpose of sparing you all unnecessary
unpleasantness in an interview which can no longer be avoided or
delayed."

"Let us sit."

It was his only answer.

When they had all complied, the District Attorney took the lead by
saying:

"I am disposed to omit all preliminaries, Mr. Roberts. We have but one
object in this visit and that is to clear up to your satisfaction, as
well as to our own, certain difficulties of an unexpected nature which
have met us in our investigation into the crime in which you, as a
director of the museum in which it occurred, and ourselves as protectors
of the public peace, are all vitally concerned."

"Granted," came in the most courteous manner from their involuntary
host. "Yet I fail to understand why so many are needed for a purpose
so laudable."

"Perhaps this will no longer surprise you, if you will allow me to draw
your attention to this chart," was the answer made to this by the
District Attorney.

Here he took from a portfolio which he carried a square of paper which he
proceeded to lay out on a table standing conveniently near.

Mr. Roberts threw a glance at it and straightened again.

"Explain yourself," said he. "I am quite at your service."

The District Attorney made, perhaps, one of the greatest efforts of his
life.

"I see that you recognize this chart, Mr. Roberts. You know when it was
made and why. But what you may not know is this: that in serving its
original purpose, it has proved to be our guide in another of equal, if
not greater, importance. For instance, it shows us quite plainly who of
all the persons present at the time of first alarm were near enough to
the Curator's office to be in the line of escape from the particularly
secluded spot from which the arrow was delivered. Of these persons, only
one fulfills all other necessary conditions with an exactness which
excuses any special interest we may feel in him. It is he who is
tabulated here as number 3."

It was said. Mr. Roberts was well acquainted with his own number. He did
not have to follow with his eye the point of the District Attorney's
finger to know upon whose name it had settled; and for a moment,
surprise, shock,--the greatest which can befall a man,--struggled with
countless other emotions in his usually impassive countenance. Then he
regained his poise, an