d the banker guilty. I don't know whether you are right or
wrong. I started after you, and have only reached the preliminaries of
my search. I am certain of but one thing, and that is, that a scratch
was on the safe-door. That scratch is my starting-point."

As he spoke, M. Lecoq took from his desk and unrolled an immense sheet
of drawing-paper.

On this paper was photographed the door of M. Fauvel's safe. The
impression of every detail was perfect. There were the five movable
buttons with the engraved letters, and the narrow, projecting brass
lock: The scratch was indicated with great exactness.

"Now," said M. Lecoq, "here is our scratch. It runs from top to bottom,
starting from the hole of the lock, diagonally, and, observe, from left
to right; that is to say, it terminates on the side next to the private
staircase leading to the banker's apartments. Although very deep at the
key-hole, it ends off in a scarcely perceptible mark."

"Yes, patron, I see all that."

"Naturally you thought that this scratch was made by the person who took
the money. Let us see if you were right. I have here a little iron box,
painted with green varnish like M. Fauvel's safe; here it is. Take a
key, and try to scratch it."

"The deuce take it!" he said after several attempts, "this paint is
awfully hard to move!"

"Very hard, my friend, and yet that on the safe is still harder and
thicker. So you see the scratch you discovered could not have been made
by the trembling hand of a thief letting the key slip."

"Sapristi!" exclaimed Fanferlot, stupefied: "I never should have thought
of that. It certainly required great force to make the deep scratch on
the safe."

"Yes, but how was that force employed? I have been racking my brain
for three days, and only yesterday did I come to a conclusion. Let us
examine together, and see if our conjectures present enough chances of
probability to establish a starting-point."

M. Lecoq abandoned the photograph, and, walking to the door
communicating with his bedroom, took the key from the lock, and, holding
it in his hand, said:

"Come here, Fanferlot, and stand by my side: there; very well. Now
suppose that I want to open this door, and you don't want me to open
it; when you see me about to insert the key, what would be your first
impulse?"

"To put my hands on your arm, and draw it toward me so as to prevent
your introducing the key."

"Precisely so. Now let us try it; go on." Fanferlot