"He has known it all along. I deemed it my neighbo'ly duty to inform him when we opened the lower level in the mine. But he won't be the loseh; no, suh; not Mistuh Howard Pelham. It'll be those po' sheep that he brought up here to-day to prepare them for the shearing—if the riveh gives him time to make the turn."

"The danger is immediate, then?" said Bigelow.

The white-haired King of Arcadia was standing on the brink of the mesa cliff, a stark figure in the white moonlight, with his hand at his ear. "Hark, gentlemen!" he commanded; and then: "Youh ears are all youngeh than mine. What do you heah?"

It was Ballard who replied: "The wind is rising on the range; I can hear it singing in the pines."

"No, suh; that isn't the wind—it's wateh; torrents and oceans of it. There have been great and phenomenal storms up in the basin all day; storms and cloud-bursts. See thah!"

A rippling wave a foot high came sweeping down the glassy surface of the reservoir lake, crowding and rioting until it doubled its depth in rushing into the foothill canyon. Passing the mine, it swept away other tons of the dump; and an instant later the water at the feet of the onlookers lifted like the heave of a great ground-swell—lifted, but did not subside.

Ballard's square jaw was out-thrust. "We did not build for any such brutal tests as this," he muttered. "Another surge like that——"

"It is coming!" cried Elsa. "The power dam in the upper canyon is gone!" and the sharer of the single Cantrell Christian name shrieked and took shelter under Bigelow's arm.

Far up the moon-silvered expanse of the lake a black line was advancing at railway speed. It was like the ominous flattening of the sea before a hurricane; but the chief terror of it lay in the peaceful surroundings. No cloud flecked the sky; no breath of air was stirring; the calm of the matchless summer night was unbroken, save by the surf-like murmur of the great wave as it rose high and still higher in the narrowing raceway. Instinctively Ballard put his arm about Elsa and drew her back from the cliff's edge. There could be no chance of danger for the group looking on from the top of the high mesa; yet the commanding roar of the menace was irresistible.

When the wave entered the wedge-shaped upper end of the Elbow it was a foam-crested wall ten feet high, advancing with the black-arched front of a tidal billow, mighty, terrifying, the cold breath of it blowing like a chill wind from the underworld upon the group of watchers. In its onrush the remains of the mine dump melted and vanished, and the heavy bulkhead timbering at the mouth of the workings was torn away, to be hurled, with other tons of floating débris, against the back-wall of the dam.