ght
neighborhood now, for I kin see some of th' landmarks my partner and
I saw. I say, let's keep on! We can cruise around a bit until we
strike th' right place. That won't take us so long as it would to go
back to the cave. Besides, if we go back, the Fogers may get ahead
of us!"

"With their broken airship?" asked Ned

"Can't they repair it?" demanded Abe.

"Hardly--up in this wild country," was Tom's opinion. "But perhaps
it WILL be just as well to keep on. I have a hazy remembrance of the
distances and directions on the map, and, though it will take longer
to hunt out the valley this way, I think we can do it. I can't
forgive myself for my carelessness! I should have kept a copy of the
map, or given one of you folks one."

But they would not hear of him blaming himself, and said it might
have happened to any one. It was decided that the map must be lost
in the big cave, and if it was there it was not likely to be found
by their enemies.

"We'll jest have t' prospect about a bit," declared Abe, "only we'll
do it in th' air instead of on th' ground."

It was dusk when the fruitless search for the map was over, and they
sat in the cabin discussing matters. The lights had not yet been
switched on, and the RED CLOUD was skimming along under the
influence of the automatic rudders and the propellers.

"Well, suppose we have supper," proposed Mr. Damon, who seemed to
think eating a remedy for many ills, mental and bodily. "Bless my
desert-spoon, but I'm hungry!"

He started toward the galley, while Tom went forward to the
pilothouse. Hardly had he reached it than there came a terrific
crash, and the airship seemed tossed back by some giant hand. Every
one was thrown off his feet, and the lights which had been turned on
suddenly went out.

"What's the matter?" cried Ned.

"Have we hit anything?" demanded Mr. Damon.

"Hit anything! I should say we had!" yelled Tom. "We've knocked a
piece off a big mountain of ice!"

As he spoke the airship began slowly settling toward the earth, for
her machinery had been stopped by the terrific impact.

CHAPTER XVIII

A FIGHT WITH MUSK OXEN

"Can I help you, Tom? What's to be done?" demanded Ned Newton, as he
rushed to where his chum was yanking on various levers and gear
wheels.

"Wait a minute!" gasped the young inventor. "I want to throw on the
storage battery, and that will give us some light. Then we can see
what We are doing." An instant later the whole