cries of alarm, I think they're
running away."

There was a lull in the snow flurry, and the white curtain seemed to
lift for a moment. The gold-seekers had a glimpse of the natives in
full retreat, with the Fogers--father and son--racing panic-stricken
after them. Tom could also see a big cave, just beyond the gold
hole, collapse and crumble to pieces like a house of cards.

"We have no time to lose!" Mr. Parker warned them. "The roof of this
cave is slowly coming down. The sides are collapsing! We must get
out!"

"Then wheel out the airship!" cried Tom. "We must save that! We
needn't fear the natives, now!"

The young inventor hurried to the RED CLOUD calling to Ned and the
others. They hastened to his side. It was an easy matter to move the
airship along on the wheels. It neared the opening of the cave. The
rumbling, roaring, grinding sound of the ice increased.

"Why--why!" cried Tom in surprise and alarm, as the craft neared the
mouth of the ice cavern, "we can't get it out--the opening is too
small! Yet it came in easily enough!"

"The cave is collapsing--growing smaller every moment!" cried Mr.
Parker. "We have only time to save our lives! Run out!"

"And leave the airship? Never!" yelled Tom.

"You must! You can't save that and your life!"

"Get axes and make the opening bigger!" suggested Ned, who, like his
chum, could not bear to think of the destruction of the beautiful
craft.

"No time! No time!" shouted Mr. Parker, frantically, "We must get
out! Save what you can from the ship--the gold--some supplies--the
guns--some food--save what you can!"

Then ensued a wild effort to get from the doomed craft what they
could--what they would need if they were to save their lives in that
cold and desolate country. Food, some blankets--their guns--as much
of the gold as they could hastily gather together--their weapons and
some ammunition--all this was carried from the cabin outside the
cave. The entrance was rapidly growing smaller. The roof was already
pressing down on the gas-bag.

Tom gave one last look at his fine craft. There were tears in his
eyes. He started into the cabin for something he had forgotten. Mr.
Parker grabbed him by the arm.

"Don't go in!" he cried hoarsely. "The cave will collapse in another
instant!" He rushed with Tom out of the cavern, and not a moment too
soon. The others were already outside.

Then with a rush and a roar, with a sound like a great explosion,
with a rendin