The snapping whirl of the cable as it parted flung him backward.

He had an instant's vision of the whole bridge-structure crumpling.

Then it vanished. From the depths rose the most awful scream, quickly smothered, that he had ever heard.

And as the b.e.s.t.i.a.l bodies went tumbling, rolling, fighting, down the rapids, he suddenly beheld the bridge footway hanging limp and swaying against the further cliff.

"Thank G.o.d! In time, in time!" he panted, staggering like a drunken man.

But all at once he beheld two of the Horde still there in front of him--the one that had flung the dart and another. They were advancing at a lope.

Allan turned and fled.

His ammunition was all spent, he knew that to face them was madness.

"I must load up again," thought he. "Then I'll make short work of them!"

Fortunately he could far outstrip them in flight. That, and that alone, had already saved him in the past week of horrible pursuit through the forests to northward. And quickly now he ran down the terrace again--down to the caves below. As he ran he shouted in Merucaan:

"Out, my people! Out with you! Out to battle! Out to war!"

Half way upward down to Cliff Villa he met Frumuos toiling upward. Him he greeted and quickly informed of the situation.

"The bridge is down!" he panted. "I cut it! The further sh.o.r.e is swarming with enemies. Two have reached this side!"

"What is this, O Kromno?" asked the man anxiously, pointing at Allan's shoulder. "Have they wounded you?"

Allan looked and saw a poisoned dart hanging loosely in his left sleeve. As he moved he could feel the point rubbing against his naked skin.

"Merciful Heaven!" he exclaimed. "Has it scratched me?"

With infinite precautions he loosened and threw off his outer garment.

He flung it, with the dart still adhering, down over the cliff.

"Look, Frumuos!" he commanded. "Search carefully and see if there be any scratch on the skin!"

The man obeyed, making a minute inspection through his mica eye-shields. Then he shook his head.

"No, Kromno," he answered. "I see nothing. But the arrow came near, near!"

Stern, tremendously relieved, gestured toward the caves.

"Go swiftly!" he commanded. "Bring up every man who still can fight.

All must have full burdens of cartridges. Even though the bridge be down, the enemy will still attack!"

"But how, since the great river lies between?"

"They can climb down those cliffs and swim the river and scramble up this side as easily as we can walk on level ground. Go swiftly! There is no time to lose!"

"I go, master. But tell me, the two who have already reached this side--shall we not first slay them?"

Allan thought. For the first time he now realized clearly the terrible peril that lay in these two Anthropoids already inside the limits of the colony.

He peered up the pathway. No sign of them above. Their animal cunning had warned them not to descend to certain death.

Now Allan knew they were at liberty inside the palisades, waiting, watching, const.i.tuting a deadly menace at every turn.

In any one of a thousand places they could lie ambushed, behind trees or bushes, or in the limbs aloft, and thence, unseen, they could discharge an indefinite number of darts.

It was now perilous in the extreme even to venture back to the palisade. Any moment might bring a flicking, stinging messenger of death. Those two, alone, might easily decimate the remaining men of the colony--and now each man was incalculably precious.

"Go, Frumuos," Allan again commanded. "For the moment we must leave those two up there. Go, muster all the fighting men and bring them up here along the terrace. I must think! Go!"

Suddenly, before the messenger had even had time to disappear round the first bend in the path, Allan found his inspiration.

"Regular warfare will never do it!" he exclaimed decisively. "They have thousands where we have tens. Before we could pick them off with our firearms they'd have exhausted all our ammunition and have rushed us--and everything would be all over.

"No; there must be some quicker and more drastic way! Even dynamite or Pulverite could never reach them all, swarming over there through miles of forest. Only one thing can stand against them--_fire!_

"With fire we must sweep and purge the world, even though we destroy it! _With fire we must sweep the world!_"

CHAPTER XXVIII

THE BESOM OF FLAME

Stern was not long in carrying out his plan.

Even before Frumnos had returned, with the seventeen men still able to bear arms, he was at work.

In Cliff Villa he hastily lashed up half a dozen fireb.a.l.l.s, of coa.r.s.e cloth, thoroughly soaked them in oil, and, with a blazing torch, brought them out to the terrace. Old Gesafam, at his command, bolted the door behind him. At all hazards, Beta and the child must be protected from any possibility of peril.

"Here, Frumnos!" cried Stern.

"Yes, master?"

"Run quickly! Fetch the strongest bow in the colony and many arrows!"

"I go, master!"

Once more the man departed, running.

"Gad! If I only had my oxygen-containing bullets ready!" thought Stern, his mind reverting to an unfinished experiment down there in his laboratory in the Rapids power-house. "_They_ would turn the trick, sure enough! They'd burst and rain fire everywhere. But they aren't ready yet; and even if they were, n.o.body could venture down there now!"

For already, plainly visible on the farther edge of the canyon, scores and hundreds of the hideous little beast-men were beginning to swarm.

Their cries, despite the contrary stiff wind, carried across the river; and here and there a dart broke against the cliff.