oxymeter, today, showed a diminution of .047 per cent. in the amount of
free oxygen in the air right on this mountain. And their plant is hardly
running yet! Wait till they get it under full swing--wait till their
pipe-lines and tanks and instruments and all their vast, infernal
apparatus of exploitation and enslavement are in operation! Even in a
week from now, or less, by the time you issue the call, Gabriel, you may
see wretches gasping in vain for breath, in some dark alley of Niagara
where the air is being drained!"

"Oh, devilish and infernal plot against the world!" said Gabriel,
bitterly. "Yet in essence, after all, no different from the system of
ten years ago, which kept food and shelter, light and fuel, under lock
and key--and made the dollar the only key to fit the lock! Yet this
seems worse, somehow; and though I die for it, my last supreme blow
shall be against such unutterable, such murderous villainy! So then,
comrades--"

He paused, suddenly, as Kate laid a hand on his arm.

"Hark! What's that?" she whispered.

Outside, somewhere, a sound had made itself heard. Then on the porch, a
loose board creaked.

Gabriel sprang to his feet. The others stood up and faced the door.

"In heaven's name, what's that outside?" demanded Craig.

On the instant, a heavy foot crashed through the panels of their door.
The door, burst open, flew back.

In the aperture, stood a man, in aviator's dress, with another dimly
visible behind him. Both these men held long, blue-nosed,
oxygen-bullet-shooting revolvers levelled at the little group around the
table.

"My God! Air Trust spies!" cried Grantham, pale as death.

"Hands up, you!" shouted the man in the doorway, with a wild triumph in
his voice. "You're caught, all of you! Not a move, you ---- ---- ----!
Hands up!"

CHAPTER XXXI.

ESCAPE!

Quick as thought, at sound of the imperative summons and sight of the
levelled weapons, Gabriel swept up most of the papers and crammed them
into the breast of his loose flannel shirt, then dashed the lamp to the
floor, extinguishing it. The room grew dark, for now the fire had burned
down to hardly more than glowing coals.

There was no panic; the men did not curse, neither did the women scream.
As though the tactic had already been agreed on, Craig tipped the table
up, making a kind of barricade; and over it Grantham's revolver,
snatched from his belt, spat viciously.

It all happened in a moment.

The forem