"Tie it under your arms," enjoined Frank.

"All right," came the answer a few seconds later. "Haul away. I can't endure the cold down here much longer."

The three boys were strong and they pulled with all their might, but for a time it seemed doubtful if they could lift the professor out of the creva.s.se as, despite his leanness, he was a fairly heavy man. He aided them, however, by digging his heels in the wall of the creva.s.se as they hoisted and in ten minutes' time they were able to grasp his hands and pull him into safety.

A draught from the vacuum bottle containing hot coffee which Frank carried soon restored the professor and he was able to describe to them how, as he was walking along, declaiming concerning the fur-bearing pollywog, the ground seemed to suddenly open under his feet and he felt himself tumbling into an abyss of unknown depth.

As the chasm narrowed, he managed to jam himself partially across the rift and in this way encountered an ice-coated ledge. One glance down showed him that if he had not succeeded in doing this his plunge would have ended in death, for the creva.s.se seemed to exist to an unknown depth beneath the surface of the earth.

"And now that I am safe and sound," said the professor, "let us hurry on. The fall hasn't reduced my eagerness to see the wrecked Viking ship."

"But the creva.s.se, how are we to pa.s.s that?" asked Frank.

"We must make a detour to the south," said the professor, "I noticed when I was down there that the rift did not extend more than a few feet in that direction. In fact, had I dared to move I might have clambered out."

The boys, not without some apprehension, stepped forward in continuance of their journey, and a few minutes later, after they had made the detour suggested by the professor, realized to their joy that they had pa.s.sed the dangerous abyss in safety.

"And now," shouted Frank, "forward for the Viking ship or--"

"Or a sell!" shouted the irrepressible Billy.

"Or a sell," echoed Frank.

With fast beating hearts they dashed on and a few minutes later stood on the edge of the mastmarked abyss, gazing downward into it.

As they did so a shout--such a shout as had never disturbed the great silences of that region--rent the air--

"The Viking ship at last. Hurray!"

The gully was about thirty feet deep and at the bottom of it, glazed with the thick ice that covered it, lay a queerly formed ship with a high prow,--carved like a raven's head.

IT WAS THE VIKING SHIP.

After all the centuries that had elapsed since she went adrift she was at last found, and to be ransacked of the treasure her dead sailors had ama.s.sed.

The first flush of the excitement over the discovery quickly pa.s.sed and the boys grew serious. The problem of how to blast the precious derelict out of the gla.s.sy coat of ice without sinking her was a serious one. Frank, after a brief survey, concluded, however, that the ice "cradle" about her hull was sufficiently thick to hold her steady while they blasted a way from above to her decks and hold.

It was useless to linger there, as they had not brought the needful apparatus with them, so they at once started back for the Golden Eagle. Frank's first care, arrived once more at the aeroplane, was to send out the good news, and it was received with "wireless acclaim" by those at Camp Hazzard.

"Will be there in two days by motor-sledge. Commence operations at once," was the order that was flashed back after congratulations had been extended. As it was too late to do anything more that night, the boys decided to commence work on the derelict in the morning. After a hearty supper they retired to bed in the cha.s.sis of the aeroplane, all as tired out as it is possible for healthy boys to be. Nevertheless, Frank, who always--as he put it--"slept with one eye open," was awakened at about midnight by a repet.i.tion of the noise of the mysterious airship.

There was no mistaking it. It was the same droning "burr" they had heard on the night following their discovery of the flaming mountain.

Waking Harry, the two lads peered upward and saw the stars blotted out as the shadowy form of the air-ship pa.s.sed above them--between the sky and themselves. All at once a bright ray of light shot downward and, after shifting about over the frozen surface for a time, it suddenly glared full on to the boys' camp.

Both lads almost uttered a cry as the bright light bathed them and made it certain that their rivals had discovered their aeroplane; but before they could utter a word the mysterious craft had extinguished the search glare and was off with the rapidity of the wind toward the west.

"They must be scared of us," said Harry at length, after a long awe-stricken silence.

"Not much, I'm afraid," rejoined Frank, with a woeful smile.

"Well, they hauled off and darted away as soon as they saw us,"

objected Harry.

"I'm afraid that that is no guarantee they won't come back," remarked Frank, with a serious face.

"You mean that they--"

"Have gone to get reinforcements and attack us," was the instant reply, "they must have trailed us with the powerful lenses of which the j.a.panese have the secret and which are used in their telescopes.

They are now certain that we have found the ship and are coming back.

It's simple, isn't it?"

The professor, when he and Billy awakened in the morning, fully shared the boys' apprehensions over the nocturnal visitor.

"If they think we have discovered the ship they won't rest till they have wrested it from us," he said soberly.

"I'm afraid that we are indeed in for serious trouble," said Frank, in a worried tone. "You see, Captain Hazzard and his men can't get here, even with the motor-sledge, for two days."

"Well, don't you think we had better abandon the ship and fly back to the camp?" suggested Billy.

"And leave that ship for them to rifle at their leisure--no," rejoined Frank, with lips compressed in determination, "we won't do that. We'll just go ahead and do the best we can--that's all."

"That's the way to talk," approved the professor, "now as soon as you boys have had breakfast we'll start for the ship, for, from what you have related, there is clearly no time to be lost."

The thought that their mysterious enemies might return at any time caused the boys to despatch the meal consisting of hot chocolate, canned fruit, pemmican, and salt beef, with even more haste than usual. Before they sat down to eat, however, Frank flashed a message to the camp telling them of their plight.

"Will start at once," was the reply, "keep up your courage. We are coming to the rescue."

This message cheered the boys up a good deal and they set out for the Viking ship with lighter hearts than they had had since the sighting of the night-flier. They packed with them plenty of stout rope, drills and dynamite. Harry carried the battery boxes and the rolls of wire to be used in setting off the charges when they were placed.

Arrived at the edge of the gully, a hole was drilled in the ice and an upright steel brace, one of the extra parts of the aeroplane, was imbedded in it as an upright, to which to attach the rope. It was soon adjusted and Frank, after they had drawn lots for the honor of being the first on board, climbed down it. He was quickly followed by the others, but any intention they might have had of exploring the ship at that time was precluded by the ice that coated her deck with the acc.u.mulation of centuries of drifting in the polar currents.

With the drill several holes were soon bored in the gla.s.sy coating and sticks of dynamite inserted. These were then capped with fulminate of mercury caps, and Harry climbed the rope to the surface of the narrow gully with the wires which were to carry the explosive spark. The others followed, and then, carrying the battery box to which the wires had been attached, withdrew to what was considered a safe distance.

"Ready?" asked Frank, his hand on the switch, when all had been adjusted.

"Let 'er go," cried Billy.

There was a click, and a split of blue flame followed by a roar that shook the ground under their feet. From the gully a great fountain of ice shot up mingled with smoke.

"I'm afraid I gave her too much," regretted Frank apprehensively, as the noise subsided and the smoke blew away. "I hope we haven't sunk her."

"That would be a calamity," exclaimed the professor, "but I imagine the ice beneath her was too thick to release her, even with such a heavy charge as you fired."

"Let's hope so," was the rejoinder.

Billy led the others on the rush back to the gulf.

All uttered a cry of amazement as they gazed over its edge.