tonation
shook the building. The ache in his head, behind and above the eyes,
became almost unbearable; his stomach revolted at the poisonous gases
through which he was groping. But he did not stop.

As he twisted and pried with his steel lever at the lock of the
trapdoor that stood between him and the open air of the housetop, he
could already hear the telltale splintering of wood and sharp orders
and muffled cries and the approaching, quick tramping of feet. He
fought at the lock like a madman, for by this time the trampling feet
were mounting the upper stairs, and doors were being battered and
wrenched from their hinges. He had at least made their work easy for
them; he had torn open the heart of Penfield's stronghold; he had
blazed a path for those officers of the law who had bowed before the
inaccessibility of the building he had disrupted single-handed!

"Good!" he cried, in his frenzied delight. "Give it to them good!
Wreck 'em, once for all; put 'em out of business!"

Then he gave a sudden relieving "Ah!"--for the sullen wood had
surrendered its bolts, and the door swung open to his upward push. The
night wind, cold and damp and clean, swept his hot and grimy face as he
pulled himself up through the opening.

Even as he did so he heard the gathering sounds below him growing
clearer and clearer. He squatted low in the darkness, and with a
furtive eye ever on the dismantled trapdoor, groped his way,
gorilla-like, closer and closer to the wall against which he knew the
janitor's ladder to be still leaning.

Then he dropped flat on his face, and wormed his way toward the nearest
chimney, not twelve feet from him, for a wet helmet had emerged from
the trap opening. A moment later a lantern was flashing and playing
about the rainy roof.

"We've got 'em! Quick, Lanigan; we've got 'em!" cried the helmeted
head exultantly, from the trapdoor, to someone below.

The next moment Durkin, prone on his face, heard the crack of a
revolver and the impact of the ball as it ricochetted from the
roof-tin, not a yard from his feet.

He no longer tried to conceal himself, but, rolling and tumbling toward
the eave-cornice, let himself over, and hung and clung there by his
hands, while a second ball whistled over him.

He felt desperately along the flat brick surface, with his kicking
feet, wondering if he had misjudged his direction, sick with a fear
that he might be dangling over an open abyss. He shifted the wei