pulled into
the central depot. "They wasted their time sending us here. Their plans
have evidently prospered better than they expected. Hell will break
loose any second now."

He turned and looked down the train as we alighted.

"I thought so," he muttered. "They dropped that private car when the
papers came aboard."

Hartman was hopelessly depressed. I tried to cheer him up, but he
ignored my effort and suddenly began talking very hurriedly, in a
low voice, as we passed through the station. At first I could not
understand.

"I have not been sure," he was saying, "and I have told no one. I have
been working on it for weeks, and I cannot make sure. Watch out for
Knowlton. I suspect him. He knows the secrets of a score of our refuges.
He carries the lives of hundreds of us in his hands, and I think he is
a traitor. It's more a feeling on my part than anything else. But I
thought I marked a change in him a short while back. There is the danger
that he has sold us out, or is going to sell us out. I am almost sure
of it. I wouldn't whisper my suspicions to a soul, but, somehow, I don't
think I'll leave Chicago alive. Keep your eye on Knowlton. Trap him.
Find out. I don't know anything more. It is only an intuition, and so
far I have failed to find the slightest clew." We were just stepping out
upon the sidewalk. "Remember," Hartman concluded earnestly. "Keep your
eyes upon Knowlton."

And Hartman was right. Before a month went by Knowlton paid for his
treason with his life. He was formally executed by the comrades in
Milwaukee.

All was quiet on the streets--too quiet. Chicago lay dead. There was no
roar and rumble of traffic. There were not even cabs on the streets. The
surface cars and the elevated were not running. Only occasionally, on
the sidewalks, were there stray pedestrians, and these pedestrians did
not loiter. They went their ways with great haste and definiteness,
withal there was a curious indecision in their movements, as though they
expected the buildings to topple over on them or the sidewalks to sink
under their feet or fly up in the air. A few gamins, however, were
around, in their eyes a suppressed eagerness in anticipation of
wonderful and exciting things to happen.

From somewhere, far to the south, the dull sound of an explosion came to
our ears. That was all. Then quiet again, though the gamins had startled
and listened, like young deer, at the sound. The doorways to all the
buildings were cl