"What's that?" asked Jack.

"By heck! It's the compass!" cried Andy. "It slipped from my pocket
when I stooped over. Now it's gone!"

There was no question of that. They could hear the instrument tinkling
far down in the unfathomable depths, striking from side to side of the
crater as it went down and down.

"We'll never see that again," spoke Mark dubiously. "Can we get back to
the projectile without it?" asked Jack.

"Oh, I fancy I can pick my trail back," answered the hunter. "It isn't
going to be easy, for there are no landmarks to guide me, but I'll do
my best. I ought to have known better than to put a compass in that
pocket."

It was not with very light hearts that they started back, and for a
time they went cautiously. Then, as they seemed to get on familiar
ground, they increased their pace and covered several miles.

"Say," remarked. Jack, as he sat down on a big stone. "I don't know how
the rest of you feel, but I'm tired. We've come quite a distance since
we picked up that tool."

"Yes, farther than it took us to find it after we left the projectile,"
added Mark. "I wonder if we're going right?"

The two boys looked at Andy. He scratched his head in perplexity.