They trotted on a little faster; the sun they had followed every day and
the fresh wagon tracks being their unfailing guides; the keen, cool air
of the plains, taking the place of that all-pervading dust and smell of
the perspiring oxen, invigorating them with its breath.

"We ain't skeered a bit, are we?" said Susy.

"What's there to be afraid of?" said Clarence scornfully. He said this
none the less strongly because he suddenly remembered that they had been
often left alone in the wagon for hours without being looked after,
and that their absence might not be noticed until the train stopped to
encamp at dusk, two hours later. They were not running very fast, yet
either they were more tired than they knew, or the air was thinner, for
they both seemed to breathe quickly. Suddenly Clarence stopped.

"There they are now."

He was pointing to a light cloud of dust in the far-off horizon, from
which the black hulk of a wagon emerged for a moment and was lost. But
even as they gazed the cloud seemed to sink like a fairy mirage to the
earth again, the whole train disappeared, and only the empty stretching
track returned. They did not know that this seemingly flat and level
plain was really undulatory, and that the vanished train had simply
dipped below their view on some further slope even as it had once
before. But they knew they were disappointed, and that disappointment
revealed to them the fact that they had concealed it from each other.
The girl was the first to succumb, and burst into a quick spasm of
angry tears. That single act of weakness called out the boy's pride and
strength. There was no longer an equality of suffering; he had become