the
bottom to the top of the staircase, and pulling it away from the wall,
on which it hung decidedly askew, revealed a round opening through which
poured a ray of blue light which could only proceed from the vault of
the adjoining study.

"No window," he repeated. "No, but an opening into the study wall which
answers the same purpose. Miss Butterworth, your eye is to be trusted
every time. I only wonder you did not pull this picture aside yourself."

"It was not hanging crooked then. Besides I was in a hurry. I had just
come from my encounter with this demented man. I had noticed the marks
on the landing, and the worn edges of the carpet, on my way upstairs. I
was in no condition to observe them on my way down."

"I see."

Miss Butterworth ran her foot to and fro over the flooring they were
examining.

"Bartow was evidently in the habit of coming here constantly," said she,
"probably to learn whether his master had need of him. Ingenious in Mr.
Adams to contrive signals for communication with this man! He certainly
had great use for his deaf-and-dumb servant. So one mystery is solved!"

"And if I am not mistaken, we can by a glance through this loophole
obtain the answer to another. You are wondering, I believe, how Bartow,
if he followed the movements of the assailant from the doorway, came to
thrust with his left hand, instead of with his right. Now if he saw the
tragedy from this point, he saw it over the assailant's shoulder,
instead of face to face. What follows? He would imitate literally the
movements of the man he saw, turn in the same direction and strike with
the same hand."

"Mr. Gryce, we are beginning to untangle the threads that looked so
complicated. Ah, what is that? Why, it's that bird! His cage must be
very nearly under this hole."

"A little to one side, madam, but near enough to give you a start. What
was it he cried then?"

"Oh, those sympathetic words about Eva! 'Poor Eva!'"

"Well, give a glance to Bartow. You can see him very well from here."

Miss Butterworth put her eye again to the opening, and gave a grunt, a
very decided grunt. With her a grunt was significant of surprise.

"He is shaking his fist; he is all alive with passion. He looks as if he
would like to kill the bird."

"Perhaps that is why the creature was strung up so high. You may be sure
Mr. Adams had some basis for his idiosyncrasies."

"I begin to think so. I don't know that I care to go back where that man
is