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.
The partners, shaking and pale, retreated hastily. A swift, upward-rising shape swept over the courtyard and was gone—one of the air-fleet now launched to meet the attackers.
Far below a sudden crumbling shudder of masonry told the Billionaire not a moment was to be lost, for already one wing of the Administration Building was swaying to its fall.