s man after all? Was his instinct, for the first time in his
active career, wholly at fault?

He had succeeded in getting a glimpse of his quarry in the privacy
of his own room, at home with his thoughts and unconscious of any
espionage, and how had he found him? Cheerful, and natural in all his
movements.

But the evening was young. Retrospect comes with later and more lonely
hours. There will be opportunities yet for studying this impassive
countenance under much more telling and productive circumstances than
these. He would await these opportunities with cheerful anticipation.
Meanwhile, he would keep up the routine watch he had planned for this
night. Something might yet occur. At all events he would have exhausted
the situation from this standpoint.

And so it came to pass that at an hour when all the other hard-working
people in the building were asleep, or at least striving to sleep, these
two men still sat at their work, one in the light, the other in the
darkness, facing each other, consciously to the one, unconsciously
to the other, across the hollow well of the now silent court. Eleven
o'clock! Twelve! No change on Brotherson's part or in Brotherson's room;
but a decided one in the place where Sweetwater sat. Objects which had
been totally indistinguishable even to his penetrating eye could now be
seen in ever brightening outline. The moon had reached the open space
above the court, and he was getting the full benefit of it. But it was
a benefit he would have been glad to dispense with. Darkness was like
a shield to him. He did not feel quite sure that he wanted this shield
removed. With no curtain to the window and no shade, and all this
brilliance pouring into the room, he feared the disclosure of his
presence there, or, if not that, some effect on his own mind of those
memories he was more anxious to see mirrored in another's discomfiture
than in his own.

Was it to escape any lack of concentration which these same memories
might bring, that he rose and stepped to the window? Or was it under one
of those involuntary impulses which move us in spite of ourselves to do
the very thing our judgment disapproves?

No sooner had he approached the sill than Mr. Brotherson's shade flew
way up and he, too, looked out. Their glances met, and for an instant
the hardy detective experienced that involuntary stagnation of the blood
which follows an inner shock. He felt that he had been recognised. The
moonlight lay