This great space was filled with gigantic architectural constructions, with amphitheaters, gorges, precipices, walls of masonry, fortresses, terraced up to the level of the eyes, temples, mountain high, all brilliant with horizontal lines of color—–­streaks of hues from a few feet to a thousand feet in width, mottled here and there with all the colors of the rainbow.

Such coloring, such harmony of tints the Pony Rider Boys never had gazed on before.  It seemed to them as if they themselves were standing in midair looking down upon a new and wonderful world.  There was neither laughter nor jest upon the lips of these brown-faced, hardy boys now.

Professor Zepplin slowly took off his hat in homage to what was there at his feet.  He wiped the perspiration from his forehead.  A glance at Tad Butler showed tear drops glistening on his cheeks.  He was trembling.  Never before had a more profound emotion taken hold of him.  Ned Rector and Walter Perkins’s faces wore expressions of fear.  No other moment in the lives of the four boys had been like this.

Dad’s face shone as with a reflected light from the Canyon that he loved so well, and that had been his almost constant companion for more than thirty years; whose moods he knew almost as well as his own, and whose every smile or frown had its meaning for him.

The travelers each forgot that there was any other human being than himself present.  They were drawn sharply to the fact that there were others present, when one of the little party of sight-seers that had come over from the hotel picked up a rock, the weight of which was almost too much for him.

The lads watched him with fascinated eyes.  The man swung the rock back and forth a few times, then hurled it over the edge.  The Pony Rider Boys waited, actually holding their breath, to catch the report when the rock should strike the bottom.

No report came.  It requires some little time for a rock to fall a mile, and when it does land it is doubtful if those at the other end of the mile would hear the report.

The faces of the Pony Riders actually paled.  This was indeed the next thing to a bottomless pit.  Walter Perkins recalled afterwards that his head had spun dizzily, Ned that he was too frightened to move a muscle.

Suddenly the silence was broken by a shout that was really an agonized yell.  The voice was Stacy Brown’s.

“Hold me!  Somebody hold me!” he screamed

The others glanced at him with disapproving eyes.  Could nothing impress Chunky?  The fat boy had begun to move forward toward the edge, both hands extended in front of him as to ward off something.

“Hold me!  I’m going to jump!  Oh, won’t somebody hold me?”

Even then only one in that little party appeared to understand.  They were paralyzed with amazement and unable to move a muscle.  The one who did see and understand was Tad Butler.  Chunky was giving way to an irresistible impulse.  He was at that instant being drawn toward the terrible abyss.