Before he could recover and regain control of his startled wits the aviator had thrown down a lever, and the great fabric was in motion.

It swept down the field like a frightened swan; and the wheels of its cha.s.sis, registering every infinitesimal irregularity in the surface of the ground, magnified them all a hundred-fold. It was like riding in a tumbril driven at top-speed over the Giant's Causeway. Lanyard was shaken violently to the very marrow of his bones; he believed that even his eyes must be rattling in their sockets....

Then the Parrott began to ascend. Singularly enough, this change was marked, at first, by no more than slight lessening of the vibration: still the machine seemed to be dashing over a cobbled thoroughfare at breakneck speed; and Lanyard found it difficult to appreciate that they were afloat, even when he looked down and discovered a hundred feet of s.p.a.ce between himself and the practice-field.

In another breath they were soaring over housetops.

Momentarily, now, the shocks became less frequent. And presently they ceased almost altogether, to be repeated only at rare intervals, when the drift of air opposing the planes developed irregularities in its velocity. There succeeded, in contrast, the sublimest peace; even the roaring of the propeller dwindled to a sustained drone; the biplane seemed to float without an effort upon a vast, still sea, flawed only occasionally by inconsiderable ripples.

Still rising, they surprised the earliest rays of the sun; and in their virgin light the aeroplane was transformed into a thing of gossamer gold.

Continually the air buffeted their faces like a flood of icy water.

Below, the scroll of the world unrolled like some vast and intricately illuminated missal, or like some strange mosaic, marvellously minute....

Lanyard could see the dial of the compa.s.s, fixed to a strut on the pilot's left. By that telltale their course lay nearly due northeast.

Already the weltering roofs of Paris were in sight, to the right, the Eiffel Tower spearing up like a fairy pillar of gold lace-work, the Seine looping the cluttered acres like a sleek brown serpent, the Sacre-Coeur a dream-palace of opalescent walls.

Versailles broke the horizon to port and slipped astern. Paris closed up, telescoped its panorama, became a mere blur, a smoky smudge. But it was long before the distance eclipsed that admonitory finger of the Eiffel.

Vauquelin manipulating the levers, the plane tilted its nose and swam higher and yet higher. The song of the motor dropped an octave to a richer tone. The speed was sensibly increased.

Lanyard contemplated with untempered wonder the fact of his equanimity: there seemed nothing at all strange in this extraordinary experience; he was by no means excited, remained merely if deeply interested. And he could detect in his physical sensations no trace of that qualmish dread he always experienced in high places: the sense he had of security, of solidity, was and ever remained wholly unaccountable in his understanding.

Of a sudden, surprised by a touch on his arm, he turned to see through the mica windows of the wind-mask the eyes of the aviator informed with importunate doubt. Infinitely mystified and so an easy prey to sickening fear lest something were going wrong with the machine, Lanyard shook his head to indicate lack of comprehension. With an impatient gesture the aviator pointed downward. Appreciating the fact that speech was impossible, Lanyard clutched the struts and bent forward. But the pace was now so fast and their elevation so great that the landscape swimming beneath his vision was no more than a brownish plain fugitively maculated with blots of contrasting colour.

He looked up blankly, but only to be treated to the same gesture.

Piqued, he concentrated attention more closely upon the flat, streaming landscape. And suddenly he recognized something oddly familiar in an approaching bend of the Seine.

"St.-Germain-en-Laye!" he exclaimed with a start of alarm.

This was the danger point....

"And over there," he reminded himself--"to the left--that wide field with a queer white thing in the middle that looks like a winged grub--that must be De Morbiban's aerodrome and his Valkyr monoplane!

Are they bringing it out? Is that what Vauquelin means? And if so--what of it? I don't see ..."

Suddenly doubt and wonder chilled the adventurer.

Temporarily Vauquelin returned entire attention to the management of the biplane. The wind was now blowing more fitfully, creating pockets--those holes in the air so dreaded by cloud pilots--and in quest of more constant resistance the aviator was swinging his craft in a wide northerly curve, climbing ever higher and more high.

The earth soon lost all semblance of design; even the twisted silver wire of the Seine vanished, far over to the left; remained only the effect of firm suspension in that high blue vault, of a continuous low of iced water in the face, together with the tuneless chanting of the motor.

After some forty minutes of this--it may have been an hour, for time was then an incalculable thing--Lanyard, in a mood of abnormal sensitiveness, began to divine additional disquiet in the mind of the aviator, and stared until he caught his eye.

"What is it?" he screamed in futile effort to lift his voice above the din.

But the Frenchman understood, and responded with a sweep of his arm toward the horizon ahead. And seeing nothing but cloud in the quarter indicated, Lanyard grasped the nature of a phenomenon which, from the first, had been vaguely troubling him. The reason why he had been able to perceive no real rim to the world was that the earth was all a-steam from the recent heavy rains; all the more remote distances were veiled with rising vapour. And now they were approaching the coast, to which, it seemed, the mists clung closest; for all the world before them slept beneath a blanket of dull grey.

Nor was it difficult now to understand why the aviator was ill at ease facing the prospect of navigating a Channel fog.

Several minutes later, he startled Lanyard with another peremptory touch on his arm followed by a significant glance over his shoulder.

Lanyard turned quickly.

Behind them, at a distance which he calculated roughly as two miles, the silhouette of a monoplane hung against the brilliant firmament, resembling, with its single spread of wings, more a solitary, soaring gull than any man-directed mechanism.

Only an infrequent and almost imperceptible shifting of the wings proved that it was moving.

He watched it for several seconds, in deepening perplexity and anxiety, finding it impossible to guess whether it were gaining or losing in that long chase, or who might be its pilot.

Yet he had little doubt but that the pursuing machine had risen from the aerodrome of Count Remy de Morbihan at St.-Germain-en-Laye; that it was nothing less, in fact, than De Morbihan's Valkyr, reputed the fastest monoplane in Europe and winner of a dozen International events; and that it was guided, if not by De Morbihan himself, by one of the creatures of the Pack--quite possibly, even more probably, by Ekstrom!

But--a.s.suming all this--what evil could such pursuit portend? In what conceivable manner could the Pack reckon to further its ends by commissioning the monoplane to overtake or distance the Parrott? They could not hinder the escape of Lanyard and Lucy Shannon to England in any way, by any means reasonably to be imagined.

Was this simply one more move to keep the pair under espionage? But that might more readily have been accomplished by telegraphing or telephoning the Pack's confreres, Wertheimer's a.s.sociates in England!

Lanyard gave it up, admitting his inability to trump up any sane excuse for such conduct; but the riddle continued to fret his mind without respite.

From the first, from that moment when Lucy's disappearance had required postponement of this flight, he had feared trouble; it hadn't seemed reasonable to hope that the Parrott could be held in waiting on his convenience for many days without the secret leaking out; but it was trouble to develop before the start from Port Aviation that he had antic.i.p.ated. The possibility that the Pack would be able to work any mischief to him, after that, had never entered his calculations. Even now he found it difficult to give it serious consideration.

Again he glanced back. Now, in his judgment, the monoplane loomed larger than before against the glowing sky, indicating that it was overtaking them.

Beneath his breath Lanyard swore from a br.i.m.m.i.n.g heart.

The Parrott was capable of a speed of eighty miles an hour; and unquestionably Vauquelin was wheedling every ounce of power out of its willing motor. Since drawing Lanyard's attention to the pursuer he had brought about appreciable acceleration.

But would even that pace serve to hold the Valkyr if not to distance it?

His next backward look reckoned the monoplane no nearer.

And another thirty minutes or go elapsed without the relative positions of the two flying machines undergoing any perceptible change.

In the course of this period the Parrott rose to an alt.i.tude, indicated by the barograph at Lanyard's elbow, of more than half a mile. Below, the Channel fog spread itself out like a sea of milk, slowly churning.

Staring down in fascination, Lanyard told himself gravely: "Blue water below that, my friend!"

It seemed difficult to credit the fact that they had made the flight from Paris in so short a time.

By his reckoning--a very rough one--the Parrott was then somewhere off Dieppe: it ought to pick up England, in such case, not far from Brighton. If only one could see...!

By bending forward a little and staring past the aviator Lanyard could catch a glimpse of Lucy Shannon.

Though all her beauty and grace of person were lost in the clumsy swaddling of her makeshift costume, she seemed to be comfortable enough; and the rushing air, keen with the chill of that great alt.i.tude, moulded her wind-veil precisely to the exquisite contours of her face and stung her firm cheeks until they glowed with a rare fire that even that thick dark mesh could not wholly quench.

The sun crept above the floor of mist, played upon it with iridescent rays, shot it through and through with a warm, pulsating glow like that of a fire opal, and suddenly turned it to a tumbled sea of gold which, apparently boundless, baffled every effort to surmise their position, whether they were above land or sea.

None the less Lanyard's rough and rapid calculations persuaded him that they were then about Mid-Channel.