"You can't blame him," said Tad, rising from his perilous position and walking calmly back to them. "I nearly got them myself."

"Got what?" demanded Stacy.

"The jiggers."

"That's it. That describes it."

Professor Zepplin, who had informed himself before starting out, now turned suddenly upon them.

"He's going to give us a lecture. Listen," whispered Tad.

"Young gentlemen, you have, perhaps, little idea of the vastness of that upon which you are now gazing."

"We know it is the biggest thing in the world, Professor," said Ned.

"Imagine, if you can," continued the Professor, without heeding the interruption, "that this amphitheatre is a real theatre. Allowing twice as much room as is given for the seat of each person in the most comfortable theatre in the world, and you could seat here an audience of two hundred and fifty millions of people. These would all be in the boxes on this side."

The boys opened their eyes at the magnitude of the figures.

"An orchestra of one hundred million pieces and a chorus of a hundred and fifty million voices could be placed comfortably on the opposite side. Can you conceive of such a scene? What do you think of it?"

"I---I think," stammered Chunky, "that I'd like to be in the box office of that show---holding on to the ticket money."

Without appearing to have heard Stacy Brown's flippant reply, Professor Zepplin began again.

"Now that you are about to explore this fairy land it is well that you be informed in advance as to what it is. The river which you see down there is the Colorado. As perhaps some of you, who have studied your geography seriously, may know, the river is formed in southern Utah by the confluence of the Green and Grand, intersecting the north-western corner of Arizona it becomes the eastern boundary of Nevada and California, flowing southward until it reaches the Gulf of California."

"Yes, sir," said the boys politely, filling in a brief pause.

"That river drains a territory of some three hundred thousand square miles, and from its source is two thousand miles long. This gorge is slightly more than two hundred miles long. Am I correct in my figures, Mr. Nance?" demanded the Professor, turning to Dad, a "contradict-me-at-your-peril" expression on his face.

"I reckon you are, sir."

"The river has a winding way-----"

"That's the way with rivers," muttered Chunky to himself.

"Millions of years have been consumed in the building of this great Canyon. In that time ten thousand feet of non-conformable strata have been deposited, elevated, tilted, and washed away; the depression of the Canyon Surface serving for the depositing of Devonian, Lower Carboniferous, Upper Carboniferous, Permian, Tria.s.sic, Jura.s.sic, Cretaceous; the formation of the vast eocene lake and its total disappearance; the opening of the earth's crust and the venting from its angry stomach the foul lavas---the mind reels and whirls and grows dizzy-----"

"So do I," almost shouted Chunky, toppling over in a heap. "Quit it!

You make me sea sick-----"

"I am amazed," bristled the Professor. "I am positively amazed that a young gentleman---"

"It was the whirling, reeling suggestion that made his head swim, I think, Professor," explained Tad, by way of helping out the fat boy.

The lecture was not continued from that point just then. The Professor postponed the rest of his recital until a more opportune time.

"Will you go down to-day, or will you wait?" asked the guide.

"I think we shall find quite enough here on the edge of the rim to occupy our minds for the rest of the day, Nance," returned the Professor.

The boys agreed to this. They did not feel as if they ever would want to leave the view that fascinated and held them so enthralled. That day they journeyed over to the hotel for dinner. The guests at the quaint hotel were much interested in the Pony Rider Boys, and late in the afternoon quite a crowd came over to visit Camp Grand, as the lads had named their camp after the pack train had arrived and the tents were pitched.

There were four tents all pitched in a row facing the Canyon, the tents in a straight line. In front the American flag was planted, the camp fire burning about midway of the line and in front, so that at night it would light up the entire company street.

They cooked their own supper, Tad attending to this. But the boys were too full of the wonderful things they had seen that day to feel their usual keen-edged appet.i.te.

The dishes put away, the Professor having become deeply absorbed in an argument with some gentlemen from the hotel regarding the "processes of deposition and subsidence of the uplift," Tad slipped away, leaving his chums listening to the conversation. Dad was also listening in open-mouthed wonder that any human being could use such long words as were being pa.s.sed back and forth without choking to death. He was, however, so absorbed in the conversation that he did not at the moment note Butler's departure. Tad pa.s.sed out of sight in the direction of the Canyon.

After a few moments had pa.s.sed, Dad stirred the fire, then he too strolled off toward the rim. Tad, fearless, regardless of the peril to himself, was lying flat on his stomach gazing down over the rim, listening to the mysterious voices of the Canyon.

"I don't want you to be here, boy," said the guide gently.

Though he had approached silently, without revealing his presence, Tad never moved nor started, the tone was so gentle, and then again the boy's mind was full of other things.

"Why don't you want me here, Mr. Nance?" Dad squatted down on the very edge of the rim, both feet banging over, one arm thrown lightly over Tad's shoulders.

"You might fall."

"What about yourself? You might fall, too. You are in more danger than am I."

"Dad is not afraid. The Canyon is his home---"

"You mean you live here?"

"The greater part of the year."

"Where?"

"Some day I will show you. It is far, far down in my beloved Canyon, where the foot of the white man seldom strays. Have you heard the strange voices of Dad's friend?"

"Yes, Dad, I have heard. I hear them now."

Both fell silent. The far away roar of the turbulent waters of the Colorado was borne to their listening ears. There were other sounds, too, mysterious sounds that came like distant moans, rising and falling, with here and there one that sounded like a sob.

"The spirit of the Canyon is sad to-night," murmured Dad.

"Why, Dad, that was the wind sighing through the Canyon."

"Yes, I know, but back of it all there is life, there is the very spirit of life. I don't know how to explain it, but I feel it deep down inside of me. I think you do, too."

"Yes, Dad, I do."

"I know you do. It's a living thing to me, kid, as it will be to you after you know their voices better and they come to know you. All those people," with a sweeping gesture toward the hotel where music and song were heard, "miss it all. What they see is a great spectacle. To see the Grand Canyon is to feel it in your heart. Seeing it in any other way is not seeing it at all."

"And do you live down there alone?"