the sight of that foot held so carelessly over the yawning
chasm, but the Professor denied the accusation. He clucked very gently
to the pony. The little animal lazily drew the foot in, and, after
trying several places, at last found a spot that appeared to suit it and
on which it placed the small foot. The boys drew a sigh of relief.

"My, but that was a narrow escape," derided Ned. "Just think of it,
Professor."

"Gid ap," commanded Professor Zepplin. "Look sharp that none of you does
worse."

Now and then reaching a spot where they could get an unobstructed view
of the distance the boys were fairly thrilled by the sight of the jagged
peaks, sparkling in the sunlight, many hidden in the clouds and too high
to be seen. It was an awesome sight and at such times stilled the merry
voices of the Pony Rider Boys as they gazed off over the array of
wonderful heights.

"What are they?" asked Ned when he first caught sight of this vista of
mountain peaks.

"The first one should be Mt. Lituya and the next Mt. Fairweather," Tad
replied.

"That is correct, according to the map," spoke up the Professor. "The
former is ten thousand feet high, the latter five thousand, five
hundred."

A series of low wondering whistles were heard from the lips of the boys.
It did not seem possible that the distance to the tops of those
mountains could be so great.

"I should like to climb one of the highest," declared Butler.

"You can't," answered the Professor sharply.

"Why not, Professor?"

"Because I shall not allow it."

"And there's another reason," announced Stacy. "You can't because you
can't. But if you did succeed in getting to the top think what sport you
could have!"

"How so?" asked Butler.

"You could do a toboggan slide two miles long. I reckon it would land
you somewhere over in Asia. Wouldn't that be funny?"

"I don't know about that," reflected Butler.

"You wouldn't know about it if you were to take the slide, either. But
how it would surprise some of those Asiatics to see a Pony Rider Boy
suddenly landing in their midst, coming from the nowhere," chuckled
Stacy.

"I rather think it would surprise almost anyone to have a Pony Rider Boy
land in his midst," answered Tad with a smiling nod.

"Is that some kind of joke?" demanded the fat boy.

"No, that's an axiom," spoke up Rector.

"An axiom?" reflected Chunky. "Oh, I know what that is. It is something
that something else revolves around, isn't it? That