"Yes, if they had some of this water up on the plateau it would be worth almost its weight in gold," declared Nance. "Water is what Arizona needs and what it has precious little of. Speaking of the danger of the river," continued Nance, "it isn't wholly the water, but the traveling boulders."
"Traveling boulders!" exclaimed the boys.
"Yes. Boulders weighing perhaps a score or more of tons are rolled over and over down the river by the tremendous power of the water, almost with the force and speed of projectiles. Now and again they will run against snags. The water dashing along behind them is suddenly checked under the surface. The result is a great up-wave, such as you have already observed. They are just as likely to go downward or sideways as upward. You never know."
"Then that is the explanation of the cause of those up-waves?" asked the Professor.
"That's the way we figure it out. But we may be wrong. Take an old man's advice and don't monkey with the river."
"I thought you said Dad's beloved Canyon would not hurt him," said Tad teasingly.
"Dad's Canyon won't. The river isn't Dad's The river is a demon. The river would scream with delight were it to get Dad in its cruel clutches," answered the old man thoughtfully, his bristling whiskers drooping to his chest. "Are you boys hungry?"
The boys were. So Dad sought out a comfortable place where they might sit down, a shelf some twenty feet above the edge of the river, whence they could see the turbulent stream for a short distance both ways. It was a wonder to them where all the water came from. The Professor called attention to his former statement that the river drained some three hundred thousand miles of territory. This explanation made the matter clearer to them.
Coffee was made, the ever-ready bacon quickly fried and there in the very heart of the Grand Canyon they ate their midday meal. Never before had they sat down to a meal amid such tremendous forces.
The meal having been finished and Dad having stretched himself out on a rock after his dinner, the boys strolled off along the river, exploring the various crevices.