ot at them from varying distances with the revolver found in
Miller's room. Beginning by holding the muzzle an inch from the
cards, he gradually increased the distance inch by inch until he
was shooting from a distance of twelve inches. Then he shot from a
distance of fifteen, twenty, twenty-five and thirty inches.

He now turned to the men who had been watching him.

"I can now say definitely that Mr. Miller was shot with the muzzle
somewhere between twelve and fifteen inches from his temple. I
still do not understand why the killer approached so close
without--"

"Morris Miller was almost stone deaf," interrupted Brasher.

"Ah, that accounts for it; that clears up something that puzzled
me."

"Since you three have conspired to make me take an interest in
crime," his glance swept Jimmy, Matthews, and McCall, "I have gone
rather exhaustively into matters that hitherto only interested me
casually. I spent two months in the Scientific Crime Detection
Laboratory of Northwestern University. Among the subjects I took
up were powder marks.

"It was obvious to me at the first glance at the wound that it was
not self-inflicted. I felt reasonably certain that the weapon was
held a greater distance from the head than it would be held if the
victim contemplated suicide. That is why I suggested the
possibility that he had held the weapon and it had gone off by
accident. That seemed a remote possibility, but still a
possibility.

"Powder marks tell quite an interesting story to the student.
Black powder will not leave the same marks at the same distance,
either in kind or degree, as will smokeless powder. The same kind
of powder fired from a weapon with a short barrel will leave burns
that differ radically from those fired from a long barrel. The
amount of powder also will make a difference.

"Black powder is merely a physical mixture of three ingredients.
The charcoal which goes into its composition is not burned at the
time of firing and remains unchanged. Each little unburned
charcoal grain becomes a secondary projectile, which leaves its
mark not only on the surface that received the bullet if it is
close enough, but also makes little pits on the base of the
bullet.

"Smokeless or semi-smokeless powder is a chemical compound in
which the ingredients are radically changed in form. At the time
of firing, smokeless powder is practically all burned and only
gases are left, leaving neither soot nor pits on, the base of