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.