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 fireballs, of coarse 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, nobody could venture down there now!”

For already, plainly visible on the farther edge of the cañon, 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.