He had no more than arrived at this conclusion when a sharp, startled movement, that rocked the planes, drew his attention to the man at his side.

Glancing in alarm at the aviator's face, he saw it as white as marble--what little of it was visible beyond and beneath the wind-mask.

Vauquelin was holding out an arm, and staring at it incredulously; Lanyard's gaze was drawn to the same spot--a ragged perforation in the sleeve of the pilot's leather surtout, just above the elbow.

"What is it?" he enquired stupidly, again forgetting that he could not be heard.

The eyes of the aviator, lifting from the perforation to meet Lanyard's stare, were clouded with consternation.

Then Vauquelin turned quickly and looked back. Simultaneously he ducked his head and something slipped whining past Lanyard's cheek, touching his flesh with a touch more chill than that of the icy air itself.

"d.a.m.nation!" he shrieked, almost hysterically. "That madman in the Valkyr is firing at us!"

XXVI

THE FLYING DEATH

Steadying himself with a splendid display of self-control and sheer courage, Captain Vauquelin concentrated upon the management of the biplane.

The drone of its motor thickened again, its speed became greater, and the machine began to rise still higher, tracing a long, graceful curve.

Lanyard glanced apprehensively toward the girl, but apparently she remained unconscious of anything out of the ordinary. Her face was still turned forward, and still the wind-veil trembled against her glowing cheeks.

Thanks to the racket of the motor, no audible reports had accompanied the sharp-shooting of the man in the monoplane; while Lanyard's cry of horror and dismay had been audible to himself exclusively. Hearing nothing, Lucy suspected nothing.

Again Lanyard looked back.

Now the Valkyr seemed to have crept up to within the quarter of a mile of the biplane, and was boring on at a tremendous pace, its single spread of wings on an approximate level with that of the lower plane of the Parrott.

But this last was rising steadily....

The driver's seat of the Valkyr held a m.u.f.fled, burly figure that might be anybody--De Morbihan, Ekstrom, or any other homicidal maniac. At the distance its actions were as illegible as their results were unquestionable: Lanyard saw a little tongue of flame lick out from a point close beside the head of the figure--he couldn't distinguish the firearm itself--and, like Vauquelin, quite without premeditation, he ducked.

At the same time there sounded a harsh, ripping noise immediately above his head; and he found himself staring up at a long ragged tear in the canvas, caused by the bullet striking it aslant.

"What's to be done?" he screamed pa.s.sionately at Vauquelin.

The aviator shook his head impatiently; and they continued to ascend; already the web of gold that cloaked earth and sea seemed thrice as far beneath their feet as it had when Vauquelin made the appalling discovery of his bullet-punctured sleeve.

But the monoplane was doggedly following suit; as the Parrott rose, so did the Valkyr, if a trace more slowly and less flexibly.

Lanyard had read somewhere, or heard it said, that monoplanes were poor machines for climbing. He told himself that, if this were true, Vauquelin knew his business; and from this reflection drew what comfort he might.

And he was glad, very glad of the dark wind-veil that shrouded his face, which he believed to be nothing less than a mask of panic terror.

He was, in fact, quite rigid with fright and horror. It were idle to argue that only unlikely chance would wing one of the bullets from the Valkyr to a vital point: there was the torn canvas overhead, there was that hole through Vauquelin's sleeve....

And then the barograph on the strut beside Lanyard disappeared as if by magic. He was aware of a slight jar; the framework of the biplane quivered as from a heavy blow; something that resembled a handful of black crumbs sprayed out into the air ahead and vanished: and where the instrument had been, nothing remained but an iron clamp gripping the strut.

And even as any one of these bullets might have proved fatal, their first successor might disable the aviator if it did not slay him outright; in either case, the inevitable result would be death following a fall from a height, as recorded on the barograph dial an instant before its destruction, of more than four thousand feet.

They were still climbing....

Now the pursuer was losing some of the advantage of his superior speed; the Parrott was perceptibly higher; the Valkyr must needs mount in a more sweeping curve.

None the less, Lanyard, peering down, saw still another tongue of flame spit out at him; and two bullet-holes appeared in the port-side wings of the biplane, one in the lower, one in the upper spread of canvas.

White-lipped and trembling, the adventurer began to work at the fastenings of his surtout. After a moment he plucked off one of his gloves and cast it impatiently from him. A-sprawl, it sailed down the wind like a wounded sparrow. He caught Vauquelin's eye upon him, quick with a curiosity which changed to a sudden gleam of comprehension as Lanyard, thrusting his hand under the leather coat, groped for his pocket and produced an automatic pistol which Ducroy had pressed upon his acceptance.

They were now perhaps a hundred feet higher than the Valkyr, which was soaring a quarter of a mile off to starboard. Under the guidance of the Frenchman, the Parrott swooped round in a narrow circle until it hung almost immediately above the other--a manoeuvre requiring, first and last, something more than five minutes to effect.

Meanwhile, Lanyard reb.u.t.toned his surtout and clutched the pistol, trying hard not to think. But already his imagination was sick with the thought of what would ensue when the time came for him to carry out his purpose.

Vauquelin touched his arm with urgent pressure; but Lanyard only shook his head, gulped, and without looking surrendered the weapon to the aviator....

Bearing heavily against the chest-band, he commanded the broad white spread of the Valkyr's back and wings. Invisible beneath these hung the motor and driver's seat.

An instant more, and he was aware that Vauquelin was leaning forward and looking down.

Aiming with what deliberation was possible, the aviator emptied the clip of its eight cartridges in less than a minute.

The vicious reports rang out against the drum of the motor like the cracking of a blacksnake-whip.

Momentarily, Lanyard doubted if any one bullet had taken effect. He could not, with his swimming vision, detect sign of damage in the canvas of the Valkyr.

He saw the empty automatic slip from Vauquelin'p numb and nerveless fingers. It vanished....

A frightful fascination kept his gaze constant to the soaring Valkyr.

Beyond it, down, deep down a mile of emptiness, was that golden floor of tumbled cloud, waiting ...

He saw the monoplane check abruptly in its strong onward surge--as if it had run, full-tilt, head-on, against an invisible obstacle--and for what seemed a round minute it hung so, veering and wobbling, nuzzling the wind. Then like a sounding whale it turned and dived headlong, propeller spinning like a top.

Down through the eighth of a mile of s.p.a.ce it plunged plummet-like; then, perhaps caught in a flaw of wind, it turned sideways and began to revolve, at first slowly, but with increasing rapidity in its fatally swift descent.

Toward the beginning of its revolutions, something was thrown off, something small, dark and sprawling ... like that glove which Lanyard had discarded. But this object dropped with a speed even greater than that of the Valkyr, in a brace of seconds had diminished to the proportions of a gnat, in another was engulfed in that vast sea of golden vapour.

Even so the monoplane itself, scarcely less precipitate, spun down through the abyss and plunged to oblivion in the fog-rack....

And Lanyard was still hanging against the chest-band, limp and spent and trying not to vomit, when, of a sudden and without any warning whatever, the stentorian chant of the motor ceased and was blotted up by that immense silence, by the terrible silence of those vast solitudes of the upper air, where never a sound is heard save the voices of the elements at war among themselves: a silence that rang with an accent as dreadful as the crack of Doom in the ears of those three suspended there, in the heart of that unimaginably pellucid and immaculate radiance, in the vast hollow of the heavens, midway between the deep blue of the eternal dome and the rose and golden welter of the fog--that fog which, cloaking earth and sea, hid as well every vestige of the tragedy they had wrought, every sign of the murder that they had done that they themselves might not be murdered and cast down to destruction.

And, its propeller no longer gripping the air, the aeroplane drifted on at ever-lessening speed, until it had no way whatever and rested without motion of any sort; as it might have been in the cup of some mighty and invisible hand, held up to that stark and merciless light, under the pa.s.sionless eye of the Infinite, to await a Judgment....

Then, with a little shudder of hesitation, the planes dipped, inclined slightly earthwards, and began slowly and as if reluctantly to slip down the long and empty channels of the air.

At this, rousing, Lanyard became aware of his own voice yammering wildly at Vauquelin: