"'Tis fair spooky," whispered Jarvis to Dave. "'Ow does 'e know 'ow 'e should go? Can 'e see in the dark? 'Ow'd 'e come by the name Pant anyway?"

"Langlois give it to him," Dave whispered back, "the fellow that was killed here, you know. He claimed Pant could see in the dark and began calling him 'Panther Eye.' The men cut it down to 'Panther,' then to 'Pant.' That's all I know about it."

"'E's rightly named," growled Jarvis, as he fumbled his way through the hole in the dark.

"This way," came the low whisper of Pant. "As you were, hand to shoulder."

Only the soft pat-pat of their footfalls on the floor of what appeared to be a narrow runway broke the tomb-like silence of the place. Now and again, as they moved forward, Dave Tower felt his shoulder brush some unseen object. Each time he shivered and shrank back. He expected at any moment to hear the roar of rifles, to find himself engaged in deadly combat with the mysterious robbers who had looted the mine of its treasure while they worked within a stone's throw of it.

Twice they paused. A silence so deep that it was painful ensued. No sound came. They marched solemnly on. And now, they had struck a steep incline.

"Down low; down low; down low," came whispered back from man to man.

They stooped to an almost creeping posture and began to climb. The ascent was steep as a stair. Twice Dave lost his footing, and once came near sending his rifle crashing to the frozen earth. Some one behind was less fortunate. There came the clang of steel, then deathly silence.

Again they crept upward. Suddenly a ray of light cut through the gloom. In another second, they were in a veritable flood of light. And yet, as they glanced rapidly to right and left, they saw walls of rock. Above them too was a vaulted ceiling. Only before them was light. What could it mean?

In an instant they knew. Leaping toward the opening, they expressed their surprise in unchecked exclamations.

"A balloon! A balloon!"

It was true. It seemed to them, as they looked, that the whole side of the mountain had burst open and allowed a giant dirigible balloon to float out from its depth.

What had really happened was evident. These robbers, having located the rich mine and having no concession to mine it, had discovered this natural cave and had cut a channel from it to the place of the gold deposit. They had reached the point by balloon. Having deflated it, they had stowed it away in the cave and had blocked the entrance of the cave with snow. The next blizzard had defaced every sign of their presence. Doubtless there had been a small secret entrance to the cave which none of Johnny Thompson's men had discovered.

"They're gone!" exclaimed Dave.

"And I 'ates to think 'ow much gold they took with 'em," mourned Jarvis.

"Quick, the airplane!" shouted Pant, turning to the two aviators. "There's a machine gun on it. We'll halt them yet. I better go with you. Some of the rest of you explore the interior here. They may not have taken the gold."

Dave Tower snapped on his flashlight, and, after taking one more look at the giant black "sausage" in the sky, turned to a.s.sist the others in the exploration of the looted mine. He had little hope of discovering the treasure, but he did want to see how they had accomplished the task.

One more question crowded its way to the front: "How had they killed Frank Langlois?"

CHAPTER VIII

THREE MEN DISAPPEAR

It was the dirigible balloon that Johnny Thompson saw as he rounded the point of the hill in his wild flight from the Bolshevik band.

With his dogs grouped about him, he stood and gazed at it in speechless astonishment. Where had it come from? What was its mission? Whither was it going? These and many other questions sped through his mind as the balloon rose lazily in air.

Scarcely a moment had pa.s.sed when a sound arrested his attention. It was the thunder of a powerful gasoline engine. He guessed that it was the motor of his own airplane. He had not long to doubt, for in a second the machine came swooping into sight. It made directly toward the clumsy sausage. Lithe and bird-like it tore away after the balloon.

Was this a friendly visit or an attack? The answer came in a series of noisy punctuations--the rat-tat-tat of a machine gun.

This balloon then was an enemy. Dimly the truth entered Johnny's mind. He was beginning to connect the balloon with the little yellow men who had attacked him, and with the earth shudder, but how it all fitted in he could not tell. Who was the enemy?

His eyes were on the two ships of the sky. The airplane, having circled close to the cabin of the balloon, had fired a volley, whether directly at it or above or below it, he could not tell. Now the plane circled close again. But what was this? A man was climbing to the upper rigging of the plane. Now he was standing, balancing himself directly on top. Johnny recognized the slim figure of Pant. Now the plane, with engine dead, drifted toward the cabin of the balloon. They were almost even with it.

There came three snorts of the engine and the plane shot beneath the cabin, then out on the other side. But Pant? Where was he? He was not on the upper surface of the plane nor climbing down on the rigging.

Johnny sat down dizzily. Cold perspiration stood out on his brow. The excitement, following hours of fatigue and near starvation, was too much for him; his head swam; his eyes blurred.

But he shook himself free from these sensations and gazed skyward. He expected to see Pant come crashing down to earth. He did not. There could be but one answer: he had leaped in midair for the underrigging of the cabin of the balloon and had caught it. What a feat! It made Johnny's head dizzy to think of it. He did not doubt for one moment that Pant would do it. But what could be his purpose? Had the balloon broken loose? Was it drifting free, a derelict? This he could not believe, for the thing had seemed to travel in a definite direction. Besides, if this was true, why the machine-gun fire? Had they killed the only occupants? Johnny hoped not. He hated death. Whatever the men had done, he hoped they had not been killed. But why had Pant taken such chances?

Then as he looked, he saw a package drop over the side of the cabin. It fell straight downward, with tremendous velocity. But there came a sudden check. It was attached to a parachute. The parachute had opened. Its course was now marked by a little down-rush, then a pause, then a rush again.

He had been so intent on his observation of this that he did not realize that once more an object had fallen from the car. This time it was a man.

He also was attached to a parachute.

As he came into Johnny's circle of vision, the boy rose and waved his arms, crying with a hoa.r.s.e shout of joy:

"Pant! Pant! Good old Pant! He's safe!"

When Dave Tower and Jarvis led the little band of miners back through the cave, they found, as they had expected, that a small tunnel had been cut out of the frozen earth to form an entrance to the mine. Before entering this tunnel, they paused to look about them. Ranged about the walls, piled tier on tier, were black cubes of sand and gravel. From these came the glitter of yellow metal. These were cubes of pay dirt which would yield a rich return when the spring thaw came. Bits of cable, twisted coils of wire, a pair of rusty pliers, told that electricity had been employed as power for mining.

A smooth spot on the cave's floor showed where some form of engine had been set. That the power of the engine had been supplied by gasoline was shown by a great pile of empty one hundred gallon steel tanks which had been stolen from the company's supply in the sheds.

Dave picked up the pliers and rubbed the rust from them.

"They're Orientals all right," he mused. "Pliers got their stamp on 'em.

But say! These boys sure had some ideas about mining placer gold. A man could take their machine to Alaska and make a fortune. Let's have a look."

"Sure! Sure!" came from a half score of throats.

They hurried down the narrow tunnel to find themselves in the mine. Here, as in the cave, they found cubes of pay dirt piled high on every side. At the end of it all was a low square machine with a buzz-saw-like wheel extending from it. The power wires, still attached to it, had been cut some ten feet from it.

"'E's a clever one!" said Jarvis.

"I'll say so," agreed Dave.

Before Pant leaped from the balloon, after throwing overboard the two hundredweight sack of gold which the yellow men, in their fright at the machine-gun fire, had deserted in the outer cabin, he performed one other valuable service. He threw over the heavy anchor, which was attached to a steel cable.

The anchor shot like a plummet for the ground and proceeded to hang itself securely in a corner of rock. The progress of the balloon was instantly halted. Still filled with terror at the machine-gun fire, the yellow men took to their parachutes. On landing, they made good their escape by losing themselves in the rocky ledges which rose up from the sea sh.o.r.e. It was useless to pursue them there.

By the time all this had happened, Dave and Jarvis, with their men, had come out from the mine and had joined Johnny, who, still prancing about in his ridiculous costume, was rejoicing with Pant over the sudden enriching of their treasure-h.o.a.rd.

"Get a windla.s.s," said Dave. "We'll bring that giant bird to earth. There may be more treasure aboard her."