old man and Waldron wrenched the
steel door open.

"_Me! Me! Let me in! Me! Save me!_" howled Herzog, dragging himself
toward them.

They only laughed derisively, with howls of demoniacal scorn.

"You slave! You cur!" shouted Waldron, and spat at him as he drew the
vault door shut. "You cringing dog--stay there, now, and face it!"

The great door boomed shut. In the cool of the winding stairway of steel
which led, lighted by electricity, to the trap-door and the ladder down
into the tremendous vaults, the world-masters breathed deeply once more,
respited from death.

Herzog, screaming like a fiend in torment, clawed at the impenetrable
steel door, raved, begged, entreated, and tore his fingers on the lock.

No answer, save the muffled echo of a jeer, from within.

_Boom!_

What was that?

Mad with terror though he was, he whirled about, and faced the room now
quivering with heat.

Even as he looked, a great gap yawned in the western wall, farthest from
the flame-belching oxygen-tank that had been struck.

Through this gap, pouring irresistibly as the sea, swept a tide of
attackers, storming the inner citadel of the infernal, world-strangling
Air Trust.

At the head of this victorious army, this flood triumphant of the
embattled proletaire, Herzog's staring eyes caught a moment's glimpse of
a dreaded face--the face of Gabriel Armstrong.

Gasping, the coward and tool of the world-masters made one supreme
decision. Close by, a rack of vials stood. He whirled to it, snatched
out a tiny bottle and waiting not even to draw the cork--craunched the
bottle, glass and all, in his fang-like, uneven teeth.

An instant change swept over him. His staring eyes closed, his head fell
forward, his whole body collapsed like an empty sack. He fell, twitched
once or twice, and was dead--dead ere the attackers could reach the door
of steel where his bestial masters had betrayed him.

Thus perished Herzog, coward and tool, a victim of the very forces he
himself had helped create.

And at the moment of his death, the masters he had cringed to and had
served, sneering with scorn at him even in their mortal terror, were
tremblingly descending the long metal ladder to the impregnable vaults
of steel below.

CHAPTER XXXVI.

THE STORMING OF THE WORKS.

Plunged into the abyss of mist and flame by the attack of the Air Trust
_epervier_, Gabriel had abandoned himself for lost. Death, mercifully
swift, he had felt cou