The major, red with excitement and impatience, still had a hand on the machine-gun. He was patting it slightly, his face eloquent of longing and regret.

"Still pinning your faith to steel-jacketed streams of bullets, are you, as against ion-jacketed streams of vibrations?" the Master rallied him. "We shall see, immediately, whether you're right or _I_ am! Bullets are all well enough in their place, Major, but electrons are sometimes necessary. Vibrations, Major--I pin my faith to vibrations."

"Vibrate all you want to!" exclaimed the Celt, irefully, his eyes on the thickening swarm of flyers, some of them now plainly visible in detail against the aching smears of color flung across the eastern reaches of cloudland. "Vibrate away; but give me _this_!" He fondled the gleaming gun as if it had been a pet. "I tell you frankly, if I were in charge here, I'd let the vibrations go to h.e.l.l and begin pumping lead. I'd have all gun-crews at stations, and the second we got in range I'd open with all six Lewises!"

"Yes, and Nissr would go crumpling down, a minute later, a blazing sieve fore-and-aft--wings, tanks, fuselage, everything riddled with thousands of bullets. Vibration is the trick, I tell you. It's everything.

"All life is vibration. When it ceases, that is death--and even dead matter vibrates. All our senses depend on vibration. Everything we feel, see, hear, taste, comes to our knowledge through vibrations.

And the receptive force in us is vibration, too. The brain is just one great, central ganglion for the taking in of vibrations.

"The secret of life, of the universe itself, is vibration. If we understood all about that, the cosmos would have no secrets from us.

So now--ah, see there, will you? See, Major, and be convinced!"

He pointed eastward, into the blazing sunrise. The out-fling of his arm betrayed more human emotion than he had yet shown. Exultation leaped to his usually impa.s.sive eyes. Surely, had not this expedition--which he had hoped would give surcease from ennui and stir the pulses--had it not already yielded dividends? Had it not already very richly repaid him?

"See there, now!" he cried again, and gripped the rail with nervous hands.

"Lord above!" e.j.a.c.u.l.a.t.ed the major, squinting through his binoculars.

"Astonished, eh?" demanded the Master, smiling with malice. "Didn't think it would work, did you? Well, which do you choose now, Major--bullets or vibrations?"

"This--this is extraordinary!" exclaimed Bohannan. His gla.s.ses traveled to and fro, sweeping the fringelike fan of the attackers, still five or six miles away. "Faith, but this is--"

The binoculars lowered slowly, as Bohannan watched a falling plane.

Everywhere ahead there in the brazier of the dawn, as the two men stood watching from the wind-lashed gallery of the on-roaring liner, attackers were dropping. All along the line they had begun to fall, like ripe fruit in a hurricane.

Not in bursts of flame did they go plunging down the depths, gyrating like mad comets with long smoke-trailers and redly licking manes of fire. Not in shattered fragments did they burst and plumb the abyss.

No; quite intact, unharmed, but utterly powerless they fell.

Some spiraled down, like dead leaves twirling in autumnal breezes, with drunken yaws and pitches. Others in long slants volplaned toward the hidden sea, miles below the cloud-plain. A few pitched over and over, or slid away in nose-dives and tail-spins. But one and all, as they crossed what seemed an invisible line drawn out there ahead of the onrushing Eagle of the Sky, bowed to some mysterious force.

It seemed almost as if _Nissr_ were the center of a vast sphere that moved with her--a sphere through which no enemy could pa.s.s--a sphere against the intangible surface of which even the most powerful engines of the air dashed themselves in vain.

And still, as others and still others came charging up to the attack like knights in joust, they fell. One by one the white wool cushions of the cloud, gold-broidered by the magic needles of the sun, received them. One by one they faded, vanished, were no more.

So, all disappeared. Between a hundred and a hundred and twenty-five planes were silently, swiftly, resistlessly sent down in no more than twenty minutes, while the watchers stood there in the gallery, fascinated by the wondrous precision and power of this new and far-outflung globe of protection.

And again the blood-red morning sky grew clear of attackers. Again, between high heaven's black vault and the fantastic continent of cloud below, nothing remained but free vacancy. The Master smiled.

"Vibrations, my dear Major!" said he. "Neutralize the currents delivered by the magnetos of hostile planes to their spark-plugs, and you transform the most powerful engines into inert matter. Not all the finely adjusted mechanism in the world, nor the best of petrol, nor yet the most perfect skill is worth _that_," with a snap of the strong fingers, "when the spark dies.

"My device is the absolute ruler of whatever spark I direct it against. Our own ignition is screened; but all others within the critical radius become impotent. So you recognize, do you not, the uselessness of machine-guns? The groundlessness of any fears about the Air Patrol's forces?"

"Lord, but this is wonderful!" Bohannan e.j.a.c.u.l.a.t.ed. "If we'd only had this in the Great War, the Hun would have been wiped out in a month!"

"Yes, but we didn't have it," the Master smiled. "I've just finished perfecting it. Put the last touches on it hardly twenty-four hours ago. If there's ever another war, though--ah, see there, now! Here comes one lone, last attacker!"

He pointed. Far at the edge of empty cloudland, now less blood-stained and becoming a ruddy pink under the risen sun, a solitary aerial jouster had grown visible.

The last attacker appeared a feeble gnat to dance thus alone in the eye of morning. That one plane should, unaided, drive on at _Nissr's_ huge, rushing bulk, seemed as preposterous as a mosquito trying to lance a rhinoceros. The major directed a careful lens at this survivor.

"He has his nerve right in his baggage with him," announced the Celt.

"Sure, he's 'there.' There can be no doubt he's seen the others fall.

Yet--what now? He's turning tail, eh? He's on the run?"

"Not a bit of it! He's driving straight ahead. That was only a dip and turn, for better air. Ah, but he's good, that fellow! There's a man after my own heart, Major. Maybe there's more than one, aboard that plane. But there's one, anyhow, that's a real man!"

The Master pondered a moment, then again picked up the phone.

"Enemark?" he called. "That you?"

"h.e.l.lo! Yes, sir! What orders, sir?"

"Cut off the ray! Quick, there!"

"Yes, sir!" And through the phone the Master heard the _snick_ of a switch being hastily thrown.

"What's the idea, now?" demanded the major, astonished. "Going to let that plane close in on us, and maybe riddle us?"

The Master smiled, as he made answer:

"I'll chance the bullets, this time. There's a _man_ on board that plane. A _man_! And we--need men!"

The Master smiled, as he made answer:

"I'll chance the bullets, this time. There's a man on board that plane. A man! And we--need men!"

CHAPTER XVI

LECLAIR, ACE OF FRANCE

Swooping, rising, falling like a falcon in swift search of quarry, the last plane of the Azores squadron swept in toward the on-rushing Eagle of the Sky.

Undismayed by the swift, inexplicable fall of all its companions, it still thrust on for the attack. In a few minutes it had come off the port bows of the giant air-liner, no more than half a mile distant.

Now the watchers saw it, slipping through some tenuous higher cloud-banks that had begun to gather, a lean, swift, wasplike speedster: one of the Air Control Board's--the A.C.B.'s--most rapid aerial police planes. The binoculars of the Master and Bohannan drew the machine almost to fingers' touch.

"Only one man aboard her, with a machine-gun," commented the Master, eyes at gla.s.s, as he watched the flick of sunlight on the attacker's fuselage, the dip and glitter of her varnished wings, the blur of her propellers. Already the roaring of her exhaust gusted down to them.

"Ah, see? She's turning, now. Banking around! We may catch a burst of machine-gun fire, in a minute. Or, no--she's coming up on our tail, Major. I think she's going to try and board us!"

"You going to let her?" protestingly demanded Bohannan. His hand twitched against the b.u.t.t of the Lewis. "In two seconds I could sight an aft gun, sir, and blow that machine h.e.l.l-for-leather!"

"No, no--let that fellow come aboard, if he wants," the Master commanded. And with eager curiosity in his dark eyes, with vast wonder what manner of human this might be who--all alone after having seen more than a hundred comrades plunge--still ventured closing to grips, the Master watched.