"What's happened? What in th' name of b.l.o.o.d.y 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?"

"I'm going to take the RED CLOUD in there out of the storm."

"Can you do it? Is the opening big enough?"

"Plenty. It's larger than my shed at home, Jove! but I'm glad I saw that in time, or there would have been nothing left of the gas-bag!"

With skilful hands Tom turned the rudders and sent the airship down on a slant toward the earth, aiming for the entrance to the cave, which loomed up in the storm. When the craft was low enough down so that the superstructure would not sc.r.a.pe the top of the cave, Tom sent her ahead on the level. But he need have had no fears, for the hole was large enough to have admitted a craft twice the size of the RED CLOUD.

A few minutes later the airship slid inside the great cavern, as easily as if coming to rest in the yard of Tom's house. The roof of the cave was high over their heads, and they were safe from the storm. The cessation from the deafening sound of the pelting hailstones seemed curious to them at first.

"Well, bless my shoelaces! if this isn't luck!" cried Mr. Damon, as he opened the door of the cabin, and looked about the cave in which they now found themselves. It was comparatively light, for the entrance was very large, though the rear of the cavern was in gloom.

"Yes, indeed, we got to it just in time,'" agreed Tom. "Now let's see what sort of a place it is. We'll have to explore it."

"There may be a landslide, or the roof may come down on our heads,"

objected Mr. Parker.

"Oh, my dear Parker! please be a little more cheerful," begged Mr.

Damon.

The adventurers followed Tom from the airship, and all but the young inventor gazed curiously at the interior of the cave. His first thought was for his airship. He glanced up at the gas-bag, and noted several bad rents in it.

"I hope we can fix them," Tom thought dubiously.

But the attention of all was suddenly arrested by something that occurred just then. From the dark recess of the cavern there sounded a fearful yell or scream. It was echoed back a thousand-fold by the rocky walls of the cave, Then there dashed past the little group of gold-seekers a dark figure.

"Look out! It's a bear!" shouted Mr. Damon. "A bear! It's an Eskimo Indian!" yelled Abe Abercrombie, "an' he's skeered nigh t' death!

Look at him run!"

As they gazed toward the lighted entrance of the cave they saw leaping and running from it an Indian who quickly scudded out into the hail storm.

"An Indian," exclaimed Tom. "An Indian in the cave! If there's one, there may be more. I guess we'd better look to our guns. They may attack us!" and he hurried back into the airship, followed by Ned and the others.

CHAPTER XIV

THE RIVAL AIRSHIP

Well armed, the adventurers again ventured out into the cave. But they need not have been alarmed so soon, for there were no signs of any more Indians.

"I guess that one was a stray Eskimo who took shelter in here from the storm," said Abe Abercrombie.

"Are we in the neighborhood of the Alaskan Indians and Eskimos?"

inquired Ned.

"Yes, there are lots of Indians in this region," answered the old miner, "but not so many Eskimos. A few come down from th' north, but we'll see more of them, an' fewer of th' pure-blooded Indians as we get nearer th' valley of gold. Though t' my mind th' Indians an'

Eskimos are pretty much alike."

"Well, if we don't have to defend ourselves from an attack of Indians, suppose we look over the airship," proposed Tom.

"It's too dark to see very much," objected Ned. But this was overcome when Tom started up a dynamo, and brought out a portable search-light which was played upon the superstructure of the RED CLOUD. The gas-bag was the only part of the craft they feared for, as the hailstones could not damage the iron or wooden structure and the planes were made in sections, and in such a manner that rents in them could easily be repaired. So, in fact, could the gas-bag be mended, but it was harder work.

"Well, she's got some bad tears in her," announced Tom as the light flashed over the big bag. "Luckily I have plenty of the material, and some cement, so I think we can mend the rents, though it will take some days. Nothing could have been better for us than this cave. We'll stay here until we're ready to go on."

"Unless the Indians drive us out," said Abe, in a low tone.

"Why, do you think there is any danger of that?" inquired Tom.

"Well, th' brown-skinned beggars aren't any too friendly," responded the old miner. "Th' one that was in here will be sure to tell th'

others of some big spirit that flew into th' cave, an' they'll be crowdin' around here when th' storm's over. It may be we can fight 'em off, though."