But all at once the man started violently. Forward he bent, staring with widened eyes at the tube of the fuel-gage.

He blinked, as though to convince himself he had not seen aright, then stared again; and as he looked a sudden grayness overspread his face.

"_What?_" he exclaimed, then raised his head and for a moment sniffed, as though to catch some odor, elusive yet ominous, which he had for some time half sensed yet paid no heed to.

Then suddenly he knew the truth; and with a cry of fear bent, peering at the fuel-tank.

There, quivering suspended from the metal edge of the aluminum tank, hung a single clear white drop--_alcohol!_

Even as Stern looked it fell, and at once another took its place, and was shaken off only to be succeeded by a third, a fourth, a fifth!

The man understood. The ancient metal, corroded almost through from the inside, had been eaten away. That very morning a hole had formed in the tank. And now a leak--existing since what moment he could not tell--was draining the very life-blood of the machine.

"The alcohol!" cried Stern in a hoa.r.s.e, terrible voice, his wide eyes denoting his agitation. With a quivering hand he pointed.

"My G.o.d! It's all leaked out--there's not a quart left in the tank!

We're lost--lost in the bottomless abyss!"

CHAPTER XXII

LIGHTS!

At realization of the ghastly situation that confronted them, Stern's heart stopped beating for a moment. Despite his courage, a sick terror gripped his soul; he felt a sudden weakness, and in his ears the rushing wind seemed shouting mockeries of death.

As in a dream he felt the girl's hand close in fear upon his arm, he heard her crying something--but what, he knew not.

Then all at once he fought off the deadly horror. He realized that now, if ever, he needed all his strength, resource, intelligence. And, with a violent effort, he flung off his weakness. Again he gripped the wheel. Thought returned. Though the end might be at hand, thank G.o.d for even a minute's respite!

Again he looked at the indicator.

Yes, only too truly it showed the terrible fact! No hallucination, this. Not much more than a pint of the precious fluid now lay in the fuel tank. And though the engine still roared, he knew that in a minute or two it must slacken, stop and die.

What then?

Even as the question flashed to him, the engine barked its protest. It skipped, coughed, stuttered. Too well he knew the symptoms, the imperative cry: "More fuel!"

But he had none to give. In vain for him to open wide the supply valve. Vain to adjust the carburetor. Even as he made a despairing, instinctive motion to perform these useless acts--while Beatrice, deathly pale and shaking with terror, clutched at him--the engine spat forth a last, convulsive bark, and grew silent.

The whirling screws hummed a lower note, then ceased their song and came to rest.

The machine lurched forward, swooped, spiraled, and with a sickening rush, a flailing tumult of the stays and planes, plunged into nothingness!

Had Stern and the girl not been securely strapped to their seats, they must have been precipitated into s.p.a.ce by the violent, erratic dashes, drops, swerves and rushes of the uncontrolled Pauillac.

For a moment or two, instinctively despite the knowledge that it could do no good, Stern wrenched at the levers. A thousand confused, wild, terrible impressions surged upon his consciousness.

Swifter, swifter dropped the plane; and now the wind that seemed to rise had grown to be a hurricane! Its roaring in their ears was deafening. They had to fight even for breath itself.

Beatrice was leaning forward now, sheltering her face in the hollow of her arm. Had she fainted? Stern could not tell. He still was fighting with the mechanism, striving to bring it into some control. But, without headway, it defied him. And like a wounded hawk, dying even as it struggled, the Pauillac staggered wildly down the unplumbed abyss.

How long did the first wild drop last? Stern knew not. He realized only that, after a certain time, he felt a warm sensation; and, looking, perceived that they were now plunging through vapors that sped upward--so it seemed--with vertiginous rapidity.

No sensation now was there of falling. All motion seemed to lie in the uprushing vapors, dense and warm and pale violet in hue. A vast and rhythmic spiraling had possessed the Pauillac. As you have seen a falling leaf turn in air, so the plane circled, boring with terrific speed down, down, down through the mists, down into the unknown!

Nothing to be seen but vapors. No solid body, no land, no earth to mark their fall and gauge it. Yet slowly, steadily, darkness was shrouding them. And Stern, breathing with great difficulty even in the shelter of his arms, could now hardly more than see as a pale blur the white face of the girl beside him.

The vast wings of the machine, swirling, swooping, plunging down, loomed hugely vague in the deepening shadows. Dizzy, sick with the monstrous caroming through s.p.a.ce, deafened by the thunderous roaring of the up-draft, Stern was still able to retain enough of his scientific curiosity to peer upward. The sun! Could he still see it?

Vanished utterly was now the glorious...o...b.. There, seeming to circle round and round in drunken spirals, he beheld a weird, diffused, angry-looking blotch of light, tinted a hue different from any ever seen on earth by men. And involuntarily, at sight of this, he shuddered.

Already with the prescience of death full upon him, with a numb despair clutching his soul, he shrank from that ghastly, hideous aspect of what he knew must be his last sight of the sun.

Around the girl he drew his right arm; she felt his muscles tauten as he clasped her to him. Useless now, he knew, any further struggles with the aeroplane. Its speed, its plummetlike drop checked only by the huge sweep of its parachute wings, Stern knew now it must fall clear to the bottom of the abyss--if bottom there were. And if not--what then?

Stern dared not think. All human concepts had been shattered by this stupendous catastrophe. The sickly and unnatural hue of the rushing vapors that tore and slatted the planes, confused his senses; and, added to this, a stifling, numbing gas seemed diffused through the inchoate void. He tried to speak, but could not. Against the girl's cheek he pressed his own. Hers was cold!

In vain he struggled to cry out. Even had his parched tongue been able to voice a sound, the howling tempest they themselves were creating as they fell, would have whipped the shout away and drowned it in the gloom.

In Stern's ears roared a droning as of a billion hornets. He felt a vast, tremendous la.s.situde. Inside his head it seemed as though a huge, merciless pressure were grinding at his very brain. His breath came only slowly and with great difficulty.

"My G.o.d!" he panted. "Oh, for a little fuel! Oh, for a chance--a chance to fight--for life!"

But chance there was none, now. Before his eyes there seemed to darken, to dazzle, a strange and moving curtain. Through it, piercing it with a supreme effort of the will, he caught dim sight of the dial of the chronometer. Subconsciously he noted that it marked 11.25.

How long had they been falling? In vain his wavering intelligence battered at the problem. Now, as in a delirium, he fancied it had been only minutes; then it seemed hours. Like an insane man he laughed--he tried to scream--he raved. And only the stout straps that had held them both prevented him from leaping free of the hurtling machine.

"Crack!"

A lashing had given way! Part of the left hand plane had broken loose.

Drunkenly, whirling head over like an albatross shot in mid-air, the Pauillac plunged.

It righted, swerved, shot far ahead, then once again somersaulted.

Stern had disjointed, crazy thoughts of air-pressure, condensation and compression, resistance, abstruse formulae. To him it seemed that some gigantic problem in stress-calculation were being hurled at him, to solve--it seemed that, blind, deaf, dumb, some sinister and ghoul-like demon were flailing him until he answered--and that he could not answer!

He had a dim realization of straining madly at his straps till the veins started big and swollen in his hammering brows. Then consciousness lapsed.

Lapsed, yet came again--and with it pain. An awful pain in the ear-drums, that roared and crackled without cease.

Breath! He was fighting for breath!

It was a nightmare--a horrible dream of darkness and a mighty booming wind--a dream of stifling vapors and an endless void that sucked them down, down, down, eternally!

Delusions came, and mocking visions of safety. Both hands flung out as though to clutch the roaring gale, he fought the intangible.

Again he lost all knowledge.