ll might he say so. The wind had further increased in violence,
and while the storm of hailstones seemed to be about the same, the
missiles had nearly doubled in size.

"Better go down," advised Ned. "We may fall if you don't."

"Guess I will," assented Tom. "There's no use going higher. I doubt
if I could, anyhow, with all this wind pressure, and with the
gas-bag leaking. Down she is!"

As he spoke he shifted the levers, and changed the valve wheels. In
an instant the RED CLOUD began to shoot toward the earth.

"What's happened? What in th' name of Bloody Gulch are we up
ag'in'?" demanded the old miner, springing to his feet.

"We're going down--that's all," answered Tom, calmly, but he was far
from feeling that way, and he had grave fears for the safety of
himself and his companions.

Down, down, down went the RED CLOUD, in the midst of the hail storm.
But if the gold-seekers had hoped to escape the pelting of the
frozen globules they were mistaken. The stones still seemed to
increase in size and number. The gas machine register showed a
sudden lack of pressure, not due to the shutting off of the
apparatus.

"Look!" cried Ned, pointing to the dial.

"Yes--more punctures," said Tom, grimly.

"What's to be done?" asked Mr. Damon, who had finished the task Tom
allotted to him. "Bless my handkerchief! what's to be done?"

"Seek shelter if the storm doesn't stop when we get to the earth
level," answered Tom.

"Shelter? What sort of shelter? There are no airship sheds in this
desolate region."

"I may be able to send the ship under some overhanging mountain
crag," answered the young inventor, "and that will keep off the
hailstones."

Eagerly Tom and Ned, who stood together in the pilothouse peered
forward through the storm.

The wind was less violent now that they were in the lower currents
of air, but the hail had not ceased.

Suddenly Tom gave a cry. Ned looked at him anxiously. Had some new
calamity befallen them? But Tom's voice sounded more in relief than
in alarm. The next instant he called:

"Look ahead there, Ned, and tell me what you see."

"I see something big and black," answered the other lad, after a
moment's hesitation. "Why, it's a big black hole!" he added.

"That's what I made it out to be," went on Tom, "but I wanted to be
sure. It's the opening to a cave or hole in the side of the
mountain. I take it."

"You're right," agreed Ned.

"Then we're safe," declared Tom.

"Safe? How