No one could go to Tad's assistance, if, indeed, he were not beyond
assistance.

A full twenty minutes of this nerve-racking anxiety had passed when Dad
thought he saw a movement of Tad's form. A few moments later the boy
was seen to struggle to a sitting posture, where he sat for a short
time, both hands supporting his head.

Such a yell as the Pony Rider Boys uttered might have been heard clear
up on the rim of the Grand Canyon had there been any one there to hear
it. Dad danced a wild hornpipe, the Professor strode up and down,
first thrusting his hands into his pockets, then withdrawing and waving
them above his head. Stacy had settled down on the rocks with the
tears streaming down his cheeks. Stacy wasn't joking now. This
emotion was real.

They began to shout out Tad's name. It was plain that he heard them,
for he waved a listless hand then returned to his former position.

"That boy is all iron," breathed the admiring guide.

The noise of the river was so great that they could not ask him if he
were hurt seriously. But Tad answered the question himself a few
minutes later by getting up. He stood for a moment swaying as if he
would fall over again, then staggered to the wall, against which he
leaned, still holding his head.

"He must have got an awful wallop," declared Dad.

Shortly after that Tad appeared to have recovered somewhat, for he was