thing and left them in roaring blackness. He sensed the syllables, "cloud-burst!" The battle of super-heated air strata against the swift cooling at nightfall had bred storm. Vapour, surcharged with moisture, had been driven down the cañon by the suddenly engendered wind, and the dynamics of the tempest had ripped the cloud-bags with frictional electricity. Great vacuums were pierced with wild explosions and primal forces had broken loose in the ravine. Above the turmoil of the cascading water the thunder dully volleyed while they sat dumb, half suffocating. The air of the cavern seemed to have been sucked out and their lungs laboured while their pulses pounded.
The first fury of it could not have lasted many minutes. How long they never knew. But thousands of tons of water had fallen and, when the relieved clouds passed on to beat their sagging remnants against the battlements of the main cañon, the lightning, intermittent now and growing rarer, revealed the whole bed of the ravine changed into a mad torrent of foaming waves in which showed tossing trees ripped from their root-clutch flinging their broken arms about helplessly as they whirled down.
And still they sat speechless, motionless, while the flood that had come to their deliverance mounted until it lapped the level of the cave and even sent a ram in the shape of a stout cottonwood to batter down their barricade and strand there, as if to emphasize their own escape. Slowly the water subsided,
