the man's voice, "I know very well in
what chair I shall be sitting before a month has passed. I am James
Macdougal, Mr. Sanford Quest, and I have got the Ashleigh diamonds, and I
have settled an old grudge, if not of my own, of one greater than you.
That's all. A pleasant night to you!"

The door went down with a bang. Faintly, as though, indeed, the footsteps
belonged to some other world, Sanford Quest heard the two leave the house.
Then silence.

"A perfect oubliette," he remarked to himself, as he held a match over his
head a moment or two later, "built for the purpose. It must be the house
we failed to find which Bill Taylor used to keep before he was shot.
Smooth brick walls, smooth brick floor, only exit twelve feet above one's
head. Human means, apparently, are useless. Science, you have been my
mistress all my days. You must save my life now or lose an earnest
disciple."

He felt in his overcoat pocket and drew out the small, hard pellet. He
gripped it in his fingers, stood as nearly as possible underneath the spot
from which he had been projected, coolly swung his arm back, and flung the
black pebble against the sliding door. The explosion which followed shook
the very ground under his feet. The walls cracked about him. Blue fire
seemed to be playing around the blackness. He jumped on one side, barely
in time to escape a shower of bricks. For minutes afterwards everything
around him seemed to rock. He struck another match. The whole of the roof
of the place was gone. By building a few bricks together, he was easily
able to climb high enough to swing himself on to the fragments of the
hallway. Even as he accomplished this, the door was thrown open and a
crowd of people rushed in. Sanford Quest emerged, dusty but unhurt, and
touched a constable on his arm.

"Arrest me," he ordered. "I am Sanford Quest. I must be taken at once to
headquarters."

"That so, Mr. Quest? Stand on one side, you loafers," the man ordered,
pushing his way out.

"We'll have a taxicab," Quest decided.

"Is there any one else in the house?" the policeman asked.

"Not a soul," Quest answered.

They found a cab without much difficulty. It was five o'clock when they
reached the central police-station. Inspector French happened to be just
going off duty. He recognized Quest with a little exclamation.

"Got your man to bring me here," Quest explained, "so as to get away from
the mob."

"Say, you've been in trouble!" the Inspector r