ard him, and whispered:

"Sidewalk! People going by! We've never sat right here before! We
wouldn't hear them if they weren't walking on stone, or slate, or
something hard!"

The old man's heart pounded like a trip-hammer. Detroit Jim seized the
pick and began to pry the bricks loose from the arched roof of the
conduit. They worked like mad, picking, hacking, pulling, piling the
bricks softly down on the conduit floor.

Once, for an instant, Jim stopped working. "How far from the hole we
came in through, do you think we are?" he whispered.

"'Bout a hundred feet, I guess," answered the old man. "Why?"

Without replying Detroit Jim resumed his picking, picking, at the
bricks. A hundred feet from where they had entered would not be under
the sidewalk. Finally, he understood. This conduit wound around a good
deal; it would take a hundred winding feet to cover thirty
straightaway.

Finally, also, Detroit Jim turned the pick over to the old man, who,
feeling in the blackness with his hands, discovered the span as wide
as his outstretched arms, from which Detroit Jim had removed the
bricks. It was a span of yielding earth into which the old man now dug
his pick. As he worked, the loosened dirt fell upon him, upon his
head, into his eyes and nose and ears....

Abruptly the old man's pick struck the flagging above them! Detroit
Jim mounted upon the pile of bricks and shoved Anderson aside.

Jim felt along the edges of the stone clear around. It seemed to
measure about three feet by two, and to be of slate, and probably held
in place only by its contact with other stones, or by cement between
the stones. No light appeared through the crevices. Detroit Jim took
from his pocket a huge pocket-knife and with the longest blade poked
up between the main stone and the one adjoining. The blade met
resistance.

Ultimately, and abruptly, however, the blade shot through to the hilt
of the knife. Jim drew it back instantly. No light came through the
crevice.

"I smell good air," he whispered, "but I can't see a thing. It must be
night!"

They knew now what to do. The flagging must be removed at once, before
any one should go by! The hole would be big enough to let them out!
Old Man Andersen's heart leaped. It was over. They had won. Trust him
to go where they'd never get him for the Slattery business! As for
Detroit Jim, he already knew the next big trick that he would pull
off--out in Cleveland!

Ultimately, as Detroit Jim