the
bullet. Smokeless powders will also leave burns on the surface at
which the bullet is fired, but neither as black, nor deep, nor as
numerous as those left by black powder.

"Thus you see, given the same ammunition, the same weapon, it can
be ascertained by tests, with a fair degree of accuracy, at what
distance a shot was fired. The zone of black around the wound
itself, the size of powder marks, the thinness with which they are
scattered, all tell their story."

"Is this true, Professor, at distances beyond which there are
powder marks?" asked Jimmy.

"Yes, it is, but not within inches, of course, nor within a few
feet, perhaps. But even at those distances it can often be
approximated.

"Given the hypothesis that Miller was murdered, the rest was easy.
If you will go back there, Brasher, and dig your nail into the
putty holding the window nearest to the bolt, you will find it
soft; the other putty is hard. There are five rows of panes. The
one I refer to is in the middle row at the extreme left. The
killer had the forethought to use putty that was of about the same
color as old putty. But I saw on the sill some minute grains of
glass glinting in the light.

"Mrs. Horsnall, without knowing why I asked the question assured
me that there had been no repairs, such as replacing panes of
glass. When I leaned out of the window, I saw the scars in the
cement. Perfectly obvious. An active man, a strong man, probably a
left-handed man, threw a string with a stone at the end over
Miller's Folly. With this string he drew over the building a
stronger twine. Finally he drew over the top of the building a
strong rope, like a wash line, or something stronger. He then drew
both ends of the rope around, forming a loop, about the chimney.

"Using the chimney as his anchor, with his rope looped around it,
it was fairly easy for an active man. He used the kind of spurs
that electric workers use to climb up wooden poles. Those spurs
left the scars I pointed out. He had a hand hold, of course, on
the two ends of the rope hanging from the chimney about two feet
from the window.

"The rest was rather difficult. When he reached the height of the
window, the nearest pane, fortunately for him, the one near the
bolt was two feet from his perch, at his left. That is why I
suggest that he may be a left-handed man. He cut out the pane,
opened the window, went in, killed Miller and then spent some time
hiding his traces. Among these w