campfire to-night, if you wish."

"If they don't hide it," remarked Abe Blower. "And by that same token,
wouldn't it be a good idee to hide our own fire?" he continued, turning
to Tom Dillon.

"Sure!" was the prompt answer.

That night the three boys climbed several tall rocks in the vicinity of
their camp and looked around with care. But the only lights that they
could make out were miles away, and those Abe Blower stated were on the
distant railroad. Nothing like a campfire came to view.

"They are foxy and have put it in a hollow," said the old miner. "Wall,
we've done the same thing," he added, chuckling.

"Oh, if only we could locate that lost mine and put up our stakes!"
sighed Roger. "But it looks like next to a hopeless task, doesn't it,
Dave."

"Oh, I don't know, Roger," answered our hero, as cheerfully as possible,
for he saw that his chum was much downcast. "We haven't covered the
whole of the ground yet. I wouldn't give up hope, if I were you."

"I didn't think it was going to be such a job when we started," went on
the senator's son. "My, what rocks we have climbed over!" And he rubbed
a shin from which some skin had been scraped that afternoon.

"I knew it would be a hard hunt," answered our hero. "And why not? If it
was an easy matter to locate that lost mine, Abe Blower or some of those
old prospectors would have done it long ago. If we do the trick I think
it will be a great feather in our cap--in fact, I think it will be more
of a lucky accident than anything else."

"Just my way of looking at it," agreed Phil. "It's a regular
hide-and-seek game, this locating a mine among these rocks."

For a long time the three boys sat by themselves, talking about days at
Oak Hall, and about the folks left at home and about those now traveling
through Yellowstone Park. It seemed a long time since they had received
letters.

"I suppose there are letters at the hotel in Butte," said Dave, with a
little sigh.

"I'd give something to have them here," added Phil.

"If only I knew how dad was making out," murmured the senator's son. "I
suppose he is waiting every day to hear from me!"

"I hope the folks in the Park are having a good time," said Dave, after
a pause. "I suppose the main body of tourists have started for home by
now."

"Yes, they went yesterday, according to the advertised plan," answered
Phil.

"I've got an idea," said our hero, after another pause. "Do you see that
hollow just below h