moonlight, and Hamar and the
black cat were stealthily regarding one another from opposite corners
of the room. From far away--from somewhere in the very base of the
building, came the dull echo of a shout, succeeded by the violent
slamming of a door; whilst from outside, from one of the many deserted
thoroughfares below, rose the frightened cry of a fugitive woman.
Otherwise all was comparatively still.

"You're a bit early!" was Hamar's greeting, "but better that than
late. Everything is ready, and all we've got to do is to wait till
twelve. Sit down."

They did as they were bid. Presently the cat, forsaking its sanctuary,
and ignoring Curtis's solicitations, glided across the floor, and
climbing on to Kelson's knee, refused to budge. The trio sat in
silence till a few minutes before midnight, when Hamar rose, and,
selecting a spot where the moonbeams lay thickest, placed thereon the
tub of water, in which--with its face uppermost--he proceeded to float
a small mirror, set in a cheap wooden frame. He then calmly produced a
pocket knife.

"What's that for?" Kelson inquired nervously.

"Blood!" Hamar responded. "One of us must spare three drops. The
conditions demand it--and after all the ham and sausages you two have
eaten I think one of you can spare it best. Which of you shall it be?
Come, there's no time to lose!"

"Matt has more blood than I have!" Curtis growled; "but why not the
cat?"

"It would spoil our chances with it for the other experiment," Hamar
said. "It's a sulky, cross-grained brute, and would give us no end of
trouble. Besides it can bite. Look here, let's draw lots!"

Curtis and Kelson were inclined to demur; but the proposed method was
so in accordance with custom that there really did not seem any
feasible objection to raise to it. Accordingly lots were drawn--and
Hamar himself was the victim. Curtis laughed coarsely, and Kelson hid
his smiles in the cat's coat. A neighbouring clock now began to strike
twelve.

"Look alive, Leon!" Curtis cried, nudging Kelson's elbow. "Look alive
or it will be too late. The Unknown is mighty particular to a few
seconds. Let me operate on you. I've always fancied I was born to use
the knife--that I've really missed my vocation. You needn't be
afraid--there's no artery in the palm of your hand--you won't bleed to
death."

Thus goaded, Hamar pricked away nervously at his hand, and, after
sundry efforts, at last succeeded in drawing blood; three drops of