All at once the quiet of the beautiful scene was disturbed by a bowl that was plainly the voice of Stacy Brown.  Stacy, his big eyes missing little that had been going on about him, had after a time stolen away after Tad and the guide.  His curiosity had been aroused by their departure and still more by the time they had been gone.  Chunky determined to go out and investigate for himself.

He had picked his way cautiously toward the Canyon when he halted suddenly, his eyes growing large at what he saw.

“Yeow!  Look!” cried the fat boy.

Both Jim Nance and Tad sprang up.  Those in the camp heard the shout and ran toward the rim, fearing that some harm had befallen Stacy.

CHAPTER VIII

THE CITY IN THE SKIES

“What has happened now?” cried Tad, running forward.

“Look, look!”

Tad and the guide turned at the same instant gazing off across the Canyon.  At first Tad saw nothing more than he had already seen.

“I---I don’t-----”

“It’s up there in the skies.  Don’t you see?” almost shouted Stacy, pointing.

“What is it?  What is it?” shouted the others from the camp, coming up on a run.

Then Tad saw.  High up in the skies, as plainly outlined as if it were not more than a mile away, was reflected a city.  Evidently it was an Eastern city, for there were towers, domes and minarets, the most wonderful sight he had ever gazed upon.

“A—–­a mirage!”

“Yes,” said Dad.  “We see them here some times, but not often.  My friends down there are showing you many things this night.  Yes they never do that unless they are pleased.  The spirit of the Canyon is well pleased.  I was sure it would be.”

By this time the others had arrived.  All were uttering exclamations of amazement, only Tad and Dad being silent and thoughtful.  For several minutes the reflection hung suspended in the sky, then a filmy mist was drawn before it like a curtain.

“Show’s over,” announced Chunky.  “That billion orchestra will now play the overture backwards.”

“Most remarkable thing I’ve ever seen,” announced the Professor, whereupon he entered into a long scientific discussion on mirages with the gentlemen from the hotel.

Tad and the guide followed them slowly back to camp.  The conversation soon became general.  Dad was drawn into it, but he spoke no more about the things he and Butler had talked of out on the rim of the Canyon, literally hanging between heaven and earth.

“Well, what about to-morrow, Mr. Nance?” questioned the Professor, after the visitors had left them.

“I reckoned we’d go down Bright Angel Trail,” answered the guide.

“Do we take the pack train with us?”

Nance shook his head.

“Too hard a trail.  Besides we can’t get anywhere with the mules on that trail.  We’ve got to come back up here.”