e linen incased envelope; the flap
ripped away and he opened the envelope--it was empty.

Instinctively the two men glanced down at the parquetry flooring;
nothing but a thin coating of dust lay there, and Kent looked up and
down the corridor; it was deserted.

"Do you recognize the handwriting?" asked Ferguson.

"No." Kent regarded the envelope in bewilderment. "What shall we do?"

"Do? Call up the Dime Messenger Service and see where the envelope came
from; but first come and see my prisoner.

"Your prisoner?" in profound astonishment.

"Yes. I caught him chasing up the hall after you," explained Ferguson
as they hurriedly retraced their steps. "I put handcuffs on him and then
went to you. Ah, here's the light!"

"The light, yes; but where's your prisoner?" and Kent, who was a trifle
in advance of his companion in reaching the dining room, stood aside to
let Ferguson pass him.

The detective halted abruptly. The chair into which he had thrust his
prisoner was vacant. The man had disappeared.

With one accord Ferguson and Kent advanced close to the chair, and
an oath broke from the detective. On the cushion of the chair,
still bearing the impress of a human body, lay a pair of shining new
handcuffs.

Dazedly Ferguson stooped over and examined them. They were still
securely locked. Wheeling around Kent dashed through the door to his
right and Ferguson, collecting his wits, searched the rest of the
apartment with minute care. Five minutes later he came face to face with
Kent in the living room. "Not a trace of any kind," declared Kent.
"It's the same as the other night; the man's gone. It's--it's positively
uncanny."

Ferguson's face was red from mortification and his exertions combined.

"The fellow must have slipped from the room by that other door and out
through the living room as we came down the hail," he said. "Did you
shut the door of the apartment, Mr. Kent, before coming down here to
look at the prisoner?"

"Yes." Kent led the way back to the dining room. "Did you recognize the
man, Ferguson?"

"No." The detective swore softly as he stared about the room. "The
lights went out just as I tackled him."

"It was beastly luck that the fuse burned out at that second," groaned
Kent. "Fortune was with him in that; but how did the man get free of
the handcuffs?" pointing to them still lying in the chair. "We can't
attribute that to luck, unless"--staring keenly at Ferguson--"unless
you did not snap t