“Enough!” Flint snapped at him.  “When you drink, Waldron, you’re an idiot!  Now, forget all this, and let’s get down to work.  I tell you, I just now saw a signal-light up there in the mist.  There’s trouble coming tonight, as sure as we own the earth.  Trouble, maybe big trouble.  Merciful God, I—­I rather think we oughtn’t to be here, in person, eh?  We’d be much better off out of here.  If there—­there should be any fighting, you know—­”

His voice broke in a falsetto pipe.  Waldron laughed brutally.

“Bravo!” cried he, with flushed and mottled face.  “You’ll do, Flint!  I see, right now, the firing-line is the life for you!  Well, let the row come, and devil take it, say I. Better anything than—­”

The sentence was never finished, For suddenly a shattering explosion hurled a vast section of the western encircling wall outward, out into the River, and, where but a moment before, the partners had been gazing at a high concrete-and-steel barrier, with electric lights on top, now only a huge gap appeared, through which the foam-tossed current could be seen leaping swiftly onward toward the Falls.

Hurled back from the window by the force of the explosion, both men were struck dumb with terror and amaze.  Flint rallied first, and with a cry of rage, inarticulate as a beast’s howl, sprang to the window again.

Outside, a scene of desolation and wild activity was visible.  The great, paved courtyard, flanked by the turbine houses and the wall, on one hand, and on the other by the oxygen tanks’ huge bulk that loomed vaguely through the electric-lighted mist, now had begun to swarm with men.

Flint saw a few forms lying prone under the hard glare of the arcs and vacuum lights.  Others were crawling, writhing, making strange contortions.  Here, there, men with rifles were running to take their posts.  Hoarse orders were shouted, and shrill replies rang back.

Then, all at once, a kind of sputtering series of small explosions began to rip along the edge of the south wall.  And now, machine-guns began to talk, with a dry, hard metallic clatter.  And—­though whence these came, Flint could not see—­grenades began flying over the wall and bursting in the court.  Though unwounded, men fell everywhere these gas-projectiles exploded—­fell, stone dead and stiffening at once—­fell, in strange, monstrous, awful attitudes of death.

Steam began billowing up; and crackling electrical discharges leaped along the naked wires of the outer barricades.

The whole Plant shook and rattled with the violent concussions of the aerial-bomb guns, already searching the upper air with shrapnel.

Somewhere, out of the range of vision, another terrible shock made the building tremble to its nethermost foundation; and wild yells and cries, as of a charge, a repulse, a savage and determined rush, echoed through the vast enclosure.  Came a third detonation—­and, blinding in its intensity, a globe of fire burst almost beneath the window, five stories below.