e might be able to know when he reached the spot, in case it was
invisible at the time they arrived.

"Do we go?" asked Bob, when he, too, found his impatience getting the
better of him; whereupon Frank, who had evidently been waiting for some
sign, immediately took him up on it.

"If you're ready, we'll start right away," he said, quietly. "Luckily
I've been studying the face of Thunder Mountain at times during the
afternoon, and I reckon I can pilot the expedition all right."

But when Frank said this so confidently he failed to consider the
intense darkness that might baffle all his plans of campaign. Still,
Bob had the utmost confidence in his chum's ability to pull out of any
ordinary difficulty. And, since his Kentucky spirit had been fully
aroused, he was ready to accompany Frank anywhere, at any time.

Before they had been ten minutes on the way each of the boys sincerely
wished that the idea to investigate had never appealed to them, for
they began to have a rough time of it. But both were too proud to
admit the fact, and so they kept crawling along over the rocks with
their rifles slung on their backs, at times finding it necessary to
clutch hold of bushes or saplings in order to save themselves from some
tumble into holes, the actual depth of which they had no means of even
guessing in the darkness.

The light was gone. Of course that might not mean it had vanished
entirely; but at least it could no longer be seen by the boys who were
climbing upward.

Bob was hoping his comrade would propose that they call it off, and
proceed to spend the balance of the night in the first comfortable nook
they ran across. But Frank himself was loath to give the first sign of
a backdown. Consequently they continued the laborious task which was
likely to bring no reward in its train, only the satisfaction of
knowing they had accomplished the duty which they had in mind at the
time of the start.

An hour must surely have gone since they first left the little green
glade where the horses were staked out, and their supplies cached.

Bob found himself blown, and trembling all over with fatigue, because
of the unusual exertion. The heat, too, was troublesome. But not for
worlds would he be the first to complain. Frank was setting the pace,
and he must be the one to call a halt.

"Phew! this is rough sledding," remarked Frank, finally, as he stopped
to wipe his streaming face.

Of course Bob also came to a halt