"We'll stick 'ere behint th' connin'-tower," the engineer explained to Dave, as the submarine, turning, put off up the dark channel which separated the solid shore-ice from the great drift of ice-floe that lay beyond.

"If they submerge," suggested Dave, "we'll have a slim chance."

"H'I doubt if they understant that much," mumbled the engineer between chattering teeth. "H'anyway, right 'ere's where h'I stick, h'and once th' bloomin' 'eathen show a 'ead above the 'atchway, h'I 'ates t' think what'll 'appen to 'im."

"Perhaps the channel will close in and drive them ashore," suggested Dave hopefully, as he drew his mackinaw more closely about him and crouched nearer to the conning-tower, that he might avoid the cutting air and icy spray which reached him from the prow of the submarine.

"Mayhap," mumbled the engineer, snuggling close.

But the channel did not close. Also, the submarine did not submerge; it plowed straight on through the dark waters of the channel.

Night passed and the pale Arctic sun revealed the two figures huddling, half-frozen, behind the conning-tower. Daylight brought little comfort, serving only to remind them that they had no coffee for breakfast; indeed, had no breakfast at all. This set the engineer to muttering threats against the stranger who had stolen the submarine, and caused him for the hundredth time to remark:

"H'I 'ates t' think what'll 'appen t' 'em, once h'I gets me 'ands on 'em."

But the intruders stayed below while, slowly, the sun ran its brief course and then painted the ice-spires with shadows of deep purple. As the night came on, the two men were forced to move about to keep from freezing. Tip-toeing along, avoiding heavy glass windows, they conversed in low tones.

"We've been h'at h'it now goin' h'on twenty-four 'ours," murmured Jarvis. "H'it's two hundred h'an' forty miles, h'an' h'our course u'd be shorter than a reindeer's. H'if that bloomin' 'eathen that spoke of th' treasure city told truth, h'I'm one fer believin' we're nearin' th' spot."

Jarvis spoke more cheerfully than he had at any time during the strange journey. Dave smiled, as he wondered whether this was due to the fact their walk had warmed them somewhat, or his rising hopes that they would at least get to see the fabled treasure city.

"Tell me," Jarvis whispered, "do my h'old h'eyes deceive me, or h'is there a line of dark h'over t' th' right of y'?" His hand trembled as he pointed.

Dave looked long and earnestly. The moon shone very brightly. The snow brought out dark objects with such vividness that it would not be too much to expect to see large objects twenty miles away.

"I think your eyes are all right," he said slowly.

"Then that 'ud be th' forest by the river. Th' treasure city 'ud be just by the 'arbor h'at th' mouth of th' river, Dave. H'I 'ates t' think 'ow richer we'll be." The old man gripped Dave's hand.

As for Dave, he was silent. He was thinking first of the struggle that could not now be far distant. It would be a bitter fight, with odds in favor of the other party. However, he hoped the enemy had been weakened by the earlier combat. Then he thought of the men they had so unexpectedly left behind; of the Doctor who depended upon him, and of the gobs who had served under him, a boy, so faithfully. Such thoughts left him in no mood to think of treasure.

He was about to say as much to his companion when there came a rattle at the hatch of the sub.

Quickly he and the engineer crouched behind the conning-tower. Their breath coming hard, their hearts beating fast, they waited.

The throbbing of the engine stopped. The submarine glided silently on. The deathlike stillness was ended by the dull groan of a hatchway lifting. Armed each with a knife and a heavy ice-anchor, the two men waited.

* * * * *

In the meantime, during this twenty-four hours, so eventful to Dave and the engineer, other things were happening on the shore by the native village. When Rainey, who had been on guard at the time of the stealing of the "sub," had been found and brought back to consciousness, he could give no account of affairs, other than that he had been struck a violent blow on the head, and after that, remembered nothing.

For a single moment dark suspicion rested on Dave and the engineer. Some of the crew had heard them talking of the treasure city ten days' journey to the west, and had heard Jarvis remark that he "'ated t' think 'ow rich they'd be." Could it be possible they had seized the submarine and deserted the party for the sake of gain to themselves? For a moment faith wavered, then their better natures triumphed.

"Not them," they declared. "Not Dave and old Jarvis."

To this the Doctor heartily agreed. And, though his disappointment was great at having the expedition again delayed, and, perhaps, entirely thwarted, he turned his mind at once to matters of the hour.

Gathering his men about him, he outlined hastily a line of action for them in the present crisis. They were, he reasoned, in a perilous situation.

Several hundred miles west of any point reached by white whalers and traders, marooned with two hundred superstitious natives, who to-day worshipped them, but to-morrow, upon discovering the disappearance of the "spirit-whale," might turn upon them, they would be obliged to make use of every resource and every strategy to save their lives, should the submarine fail to return. His plan was, to deal fairly with the natives and keep their good will, if that were possible.

Fortunately, they had taken from the submarine ten good rifles with a hundred rounds of ammunition. Natives were seen at all hours of the day dragging behind them the carcasses of seal, oogrook (big-seal), and even polar bear. If these could be secured with the aid of such primitive weapons as harpoon and lance, they with their rifles might hope to secure an ample supply of the meat. And it had been proved that even a white man could live the winter through on a diet of meat and blubber in right proportions. They might also, at times, be able to trade for reindeer meat.

They would remain at the village until no hope remained that the submarine would return, then they would endeavor to get a store of meat, some reindeer, and deerskin sleeping bags, and make their way east to some point reached in summer by traders.

Three of the large skin-houses had already been turned over to them by the natives. These would provide ample shelter. Two were at once arranged as bunk-houses and the third as cook-shack.

When this had been done, with two men on guard, they turned in and slept.

Next morning, at six o'clock, four hours before daylight, every man was called out and assigned duties. It was the custom of the natives to depart for the hunting-ground at that hour. They should follow the same custom. Dividing themselves into two parties, one to watch camp, the other to hunt, they immediately set about their tasks.

The first day's hunt was under the direction of Azazruk, the Eskimo. The results were more than gratifying. Two ringed seals, one oogrook, ten feet long, and one young polar bear were the bag for the day.

"A full week's supply of meat," smiled the Doctor, rubbing his hands in high glee. In his interest in this new game, he had for the moment quite forgotten his great disappointment at the loss of the sub.

It was while they were smacking their lips over a hamburger, made of bear meat, that they were surprised by a young native, who rushed into their tent without the accustomed shouted salutation, seemingly quite beside himself with fear.

For some time nothing intelligible could be gathered from his excited chatter. But finally Azazruk made out that only an hour before, as he watched the reindeer, a great hairy monster had dashed at the herd, scattering it far and wide, and carrying away a yearling buck as easily as if it had been a rabbit.

"Probably a white bear," suggested Rainey.

"Not probable," said the Doctor. "A bear would eat his prey where it was slain."

"A wolf?"

"Couldn't do it."

"Well, what then?"

All eyes were turned toward the Doctor.

"You will judge me insane if I tell you what I think it was," he answered. "But here you are; I think it was a tiger."

"A tiger?"

"Tiger?"

Every man voiced his unbelief.

"A tiger in the Arctic?"

"Impossible!"

"That's absurd."

For answer the Doctor drew from his notebook a newspaper clipping, bidding Rainey read it aloud. The article was entitled "THE RUSSIAN TIGER" and was an account of the slaying of a gigantic man-eater by an American officer when American troops were stationed at Vladivostok, in eastern Russia.

"At that point," explained the Doctor, "they have about eight months of winter with a thermometer that drops far below zero. It may well be considered a part of the Arctic. Yet, as you see, they have tigers there; indeed, I am told they are not at all uncommon. So why not up here?" No one had a ready answer, and at last the Doctor spoke again:

"In the meantime, what are we going to do about it? It would seem that the natives are appealing to us for aid."

Rainey at once sprang to his feet, exclaiming:

"Count me one to go hunt the beast, whatever it is."

At once the others were on their feet shouting their eagerness for the hunt.

The Doctor chose a gob named Thompson to accompany Rainey on his "tiger hunt," or whatever it might prove to be. Rainey was well pleased at the choice, for Thompson was a sure shot and a cool, nervy hand in time of danger.

"If I don't hear from you by morning," said the Doctor, "I shall send a relief expedition."

Rainey had fully recovered from the affair of the previous day. Both he and Thompson had been among the guarding party that day, so were fresh and keen for work. They found the moonlight making the wide stretches of ice and snow light as day.

" Some night and some game!" murmured Rainey, as they emerged from the tent.

* * * * *

When the men in native garb, who had stolen the submarine, lifted the hatch to take an observation, they were utterly unaware of the presence of two figures crouching behind the conning-tower. This, in spite of the fact that the men wore their long knives strapped to their waists, gave Dave and the engineer a decided advantage—an advantage they were not slow to make the most of.

Fortunately, the robbers crowded up the hatchway, all eager to catch a first view of the reputed gold valley, in which lay the treasure city.

As the third head peeped above the hatch, Jarvis sprang at them. Swinging his ice-anchor, an ugly cudgel of bent iron with a chilled steel point, he sent two of the villains sprawling at a single blow. Meanwhile, Dave, who had grappled with the third man, made a misstep and together they plunged down the hatchway. His opponent landed full on Dave's stomach, and so crushed the breath from him that for a second the lad could not move. But instantly, he realized that he must act. The man was attempting to draw his long knife. Thrusting out a hand, Dave gripped the point of the blade in its soft leather sheath so tightly that it could not be withdrawn.

Struggling with every ounce of strength, the two men were rolling over and over on the deck. The stranger was heavier and evidently older than Dave, but the American had one advantage. He was dressed only in woolens. The heavy skin clothing of his antagonist hampered his action. In spite of this, Dave felt himself losing out in the battle. The stranger's hand was gripping closer and closer to his throat, and he felt his own hand losing its hold on the knife-blade, when he heard a welcome roar from the hatchway. It was Jarvis. With one leap he was at Dave's side. For an old man, he was surprisingly quick. Yet, he was not too quick, for the murderous knife was swinging above Dave's chest and a hand was at his throat, when Jarvis clove the assailant's skull with his ice-anchor.

With a groan the man collapsed. The knife clattered to the deck. Jarvis dropped to the floor panting.

"Are you hurt?" he gasped.

"No! Are you?"

"Not a scratch. Some jolly little weapon, them ice-h'anchors. H'I'll wear one of 'em h'in me belt from now on! H'I 'ates t' think 'ow cold th' water was when h'I pitched 'em h'in, them other two."

"Kill 'em?"

"Not that bad. But mebby they'll drown. H'I'll go see. H'I'd 'ate t' see 'em climbin' back."

He hurried up the hatchway, followed closely by Dave.

Not a sign of the two men was to be seen, either on the submarine, in the water or on the solid shore-ice, a few rods away.

"What d' y' think of that?" asked Jarvis, mopping his brow. "They're gone!"

"Perhaps they drowned."

"Mebbe drowned—mebby they're 'id h'in th' h'ice."

"Well, anyway, we're rid of them," said Dave. "We'll sew the dead one up in a blanket and throw him overboard; then we'll be going back. Think how all fussed up the Doctor will be." The boy chuckled.

"Going back?" Jarvis stared, as if unable to believe his ears. "Going back? And the treasure city within peep of h'our h'eyes. Going back, did y' say? H'I 'ates t' think 'ow rich we'll be, you an' me."

The sun was setting behind the dark line of timber. Some object at a point where the timber ended and the tundra began cast back the sunlight with a golden glow.

"D' y' see it, lad?" exclaimed the excited old man. "D'y'see it?
H'it's gold."