een dead about a day. Just
a day before this time Miss McLean an' I met James Cunningham comin'
out of the Paragon. He was white an' shaking. He was sufferin' from
nausea, an' his arm was badly strained. He explained it by sayin' he
had fallen downstairs. Later, I wondered about that fall. I'm still
wonderin'. Had he just come out of the apartment where Horikawa was
hidin'? Had the tendons of that arm been strained by a jiu-jitsu
twist? _And had he left Horikawa behind him dead on the bed?_"

James, white to the lips, looked steadily at his cousin. "A very
ingenious theory. I've always complimented you on your imagination,"
he said, a little hoarsely, as though from a parched throat.

"You do not desire to make any explanation?" Kirby asked.

"Thanks, no. I'm not on trial for my life here, am I?" answered the
oil broker quietly, with obvious irony.

His wife was sobbing softly. The man's arm went round her and
tightened in wordless comfort.

From his pocket Kirby drew the envelope upon which he had a few hours
earlier penciled the time schedule relating to his uncle's death.

"One of the points that struck me earliest about this mystery was that
the man who solved it would have to work out pretty closely the time
element. Inside of an hour ten people beside Uncle James were in his
rooms. They must 'a' trod on each other's heels right fast, I figured.
So I checked up the time as carefully as I could. Here's the schedule
I made out. Mebbe you'd like to see it." He handed the envelope to
James.

Jack rose and looked over his brother's shoulder. His quick eye ran
down the list. "I get the rest of it," he said. "But what does _X_
mean?"

"_X_ is the ten minutes of Uncle's time I can't account for. Some of
us were with him practically every other minute. _X_ is the whole
unknown quantity. It is the time in which he was prob'ly actually
killed. It is the man who _may_, by some thousandth chance, have
stepped into the room an' killed him while none of us were present,"
explained Kirby.

"If there is such an unknown man you can cut the time down to five
minutes instead of ten, providing your schedule is correct," James cut
in. "For according to it I was there part of the time and Mrs. Hull
part of the rest of it."

"Yes," agreed his cousin.

"But you may have decided that Mrs. Hull is _X_ or that I am," jeered
James. "If so, of course that ends it. No need for a judge or jury."

Kirb