Astonished and terrified as the Indians had been at the sight of the big-winged craft, high in the air above their heads, Tom and the others were no less surprised, though, of course, their fear was not exactly the same as that of the Alaskan natives.

"Do you really think that is Andy Foger?" asked Ned, as they watched the progress of the triplane.

"I'm almost sure of it," replied Tom. "That craft is built exactly as his was. but I never expected him to have such good luck sailing it."

"It isn't going very fast," objected Ned.

"No, but it can navigate pretty well, and that's something. He must have hustled to get it together and reach this point with it."

"Yes, but he didn't have to travel as far as we did," went on Ned. "He put his ship together at Sitka, and we came from Seattle."

"Bless my memoranda book!" exclaimed Mr. Damon. "The Fogers here! What's to be done about it?"

"Nothing, I guess," answered Tom. "I'd just as soon they wouldn't see us. I don't believe they will. Get back into the cave. We must use strategy now to get ahead of them. There will be a race to the valley of gold."

"Well, he served us one good turn, anyhow, though he didn't mean to," put in Abe Abercrombie.

"How?" asked Mr. Parker, who was still examining his gun, as though trying to understand it.

"He scared away them pesky natives," went on the miner. "Otherwise we might have had a fight, an' while I reckon we could have beat 'em, it's best not to fight if you kin git out of it."

The gold-seekers had withdrawn inside the mouth of the cave, where they could watch the progress of the rival airship without being seen. The Indians had disappeared beyond a snow-covered hill.

The airship of Andy Foger, for such it subsequently proved to be, floated slowly onward. Its progress was not marked with the speed of Tom's craft, though whether or not the occupants of the Anthony (as Andy had vain-gloriously named his craft after himself) were speeding up their motor, was a matter of conjecture.

The adventurers held a short consultation, while standing at the mouth of the cave watching the progress of the Anthony. It rose in the air, and circled about.

"He certainly is trying to pick us up," declared Ned.

"Well, we'll start out after him to-morrow," decided Tom. "I think all the patches will hold then."

They resumed work on the Red Cloud, and that night Tom announced that they would start in the morning. Meanwhile Andy's craft had disappeared from sight. There was no further evidence of the Indians.

"I don't reckon they'll come back," spoke Abe, grimly. "They think we are sure-enough spirits, now, able to call creatures out of the air whenever we want 'em. But still we must be on our guard."

As Mr. Parker was not of much service in helping on the airship he agreed to be a sort of guard and took his place just outside the cave, where he could make "observations," and, at the same time watch for the reappearance of Indians. They had little fear of an attack at night, for Abe said the Alaskans were not fond of darkness.

The cold seemed to increase, and, even in the sheltered cave the adventurers felt it. There were several heavy flurries of snow that afternoon, and winter seemed setting in with a vengeance. The daylight, too, was not of long duration, for the sun was well south now, and in the far polar regions it was perpetual night.

After a brief inspection of the ship the next morning, following a good night's rest, when they were not disturbed by any visits from the natives, Tom announced that they would set sail. The day was a clear one, but very cold, and the gold-seekers were glad of the shelter of the warm cabin.

The Red Cloud was wheeled from the cave, and set on a level place. There was not room enough to make a flying start, and ascend by means of the planes and propellers, so the gas-bag method was used. The generating machine was put in operation, and soon the big red bag that hovered over the craft began to fill. Tom was glad to see that none of the several compartments leaked. The bag had been well repaired.

Suddenly the Red Cloud shot up in the air. Up above the towering snow-covered crags it mounted, and then, with a whizz and a roar, the propellers were set going.

"Once more northward bound!" cried Tom, as he took his place in the pilothouse.

"And we'll see if we can beat Andy Foger there," added Ned.

All that morning the Red Cloud shot ahead at good speed. The craft had suffered no permanent damage during her fight with the hail storm, and was as good as ever. They ate dinner high in the air, while sailing over a great stretch of whiteness, where the snow lay many feet deep on the level, and where great mountain crags were so covered with the glistening mantle and a coating of ice as to resemble the great bergs that float in the polar sea.

"I wouldn't want to be wrecked here," said Ned, with a shudder, as he looked down. "We'd never get away. Does any one live down there, Abe?"

"Yes, there are scattered tribes of Indians and Alaskan natives. They live by hunting and fishing, and travel around by means of dog sledges. But it's a dreary life. Me an' my partner had all we wanted of it. An airship for mine!"

"I wonder what's become of Andy?" spoke Tom, that afternoon. "I haven't sighted him, and I've been using the powerful telescope. I can't pick him up, though he can't be so very far ahead of us."

"Let me try," suggested Ned. "Put her up a bit, Tom, where I can look down. Andy won't dare go very high. Maybe I can sight him."

The Red Cloud shot upward as the young inventor shifted the elevation rudder, and the bank clerk, with the powerful glass to his eye, swept the space below him. For half an hour he looked in vain. Then, with a little start of surprise he handed the glass to his chum.

"See what you make that out to be," suggested Ned. "It looks like a big bird, yet I haven't seen any other birds to-day."

Tom looked. He peered earnestly through the telescope for a minute, and then cried:

"It's Andy's airship! He's ahead of us! We must catch him! Ned, you and Mr. Damon speed up the motor! The race is on!"

In a few minutes the great airship was hurling herself through space, and, in less than ten minutes Andy's craft could be made out plainly with the naked eye. Fifteen minutes more and the Red Cloud was almost up to her. Then those aboard the Anthony must have caught sight of their pursuers, for there was a sudden increase in speed on the part of the unscrupulous Foger crowd, who sought to steal a march on Tom and his friends.

"The race is on!" repeated the young inventor grimly, as he pulled the speed lever over another notch.