/> "You say that you think that it's safe, and yet you won't take a crew,"

Samms argued. "In that case it isn't safe enough for you men, either. We

need you too badly to permit you to take such chances."



"You've got to let us go; because we are the only ones who are

thoroughly familiar with her theory," Rodebush insisted. "I said, and

still say, that I think it is safe. I can't prove it, however, except

mathematically; because she's altogether too full of too many new and

untried mechanisms, too many extrapolations beyond all existing or

possible data. Theoretically, she is sound, but you know that theory can

go only so far, and that mathematically negligible factors may become

operative at those velocities. We do not need a crew for a short trip.

We can take care of any minor mishaps, and if our fundamental theories

are wrong, all the crews between here and Jupiter wouldn't do any good.

Therefore we two are going--alone."



"Well, be very careful, anyway. Start out slow and take it easy."



"Start out slow? We can't! We can't neutralize half of gravity, nor half

of the inertia of matter--it's got to be everything or nothing, as soon

as the neutralizers go on. We could start out on the projectors, of

course, instead of on the neutralizers, but that wouldn't prove anything

and would only prolong the agony."



"Well, then, be as careful as you can."



"We'll do that, Chief," Cleveland put in. "We think a lot of us, and we

aren't committing suicide just yet if we can help it. And remember about

everybody staying inside when we take off--it's barely possible that

we'll take up a lot of room. Good-bye to all of you."



"Good-bye, fellows!"



The massive insulating doors were shut, the metal side of the mountain

opened, and huge, squat caterpillar tractors came roaring and clanking

into the room. Chains and cables were made fast and, mighty steel rails

groaning under the load, the space-ship upon her rolling ways was

dragged out of the Hill and far out upon the level floor of the surface

before the tractors cast off and returned to the fortress.



"Everybody is under cover." Samms informed Rodebush. The chief was

staring intently into his plate, upon which was revealed the control

room of the untried super-ship. He heard Rodebush speak to Cleveland;

heard the observer's brief reply; saw the navigator throw his

switches--then the communicator plate went blank. Not the ordinary

blankness of a cut-off, but a peculiarly disquieting fading out into

darkness. And where the great space-ship had rested there was for an

instant nothing. Exactly nothing--a vacuum. Vessel, falsework, rollers,

trucks, the enormous steel I-beams of the tracks, even the deep-set

concrete piers and foundations and a vast hemisphere of the solid

ground; all had disappeared utterly and instantaneously. But almost as

suddenly as it had been formed the vacuum was filled by a cyclonic rush

of air. There was a detonation as of a hundred vicious thunderclaps made

one, and, through the howling, shrieking blasts of wind, there rained

down upon the valley, plain and metaled mountain a veritable avalanche

of debris: bent, twisted, and broken rails and beams, splintered

timbers, masses of concrete, and thousands of cubic yards of soil and

rock. For inertia and gravitation had not been neutralized at precisely

the same instant, and for a moment everything within the radius of

action of the iron-driven gravity nullifiers of the Boise had

continued its absolute motion with inertia unimpaired. Then, left behind

immediately by the almost infinite velocity of the cruiser, all this

material had again become subject to all of Nature's everyday laws and

had crashed back to the ground.



"Could you hold your beam, Randolph?" Samm's voice cut sharply through

the daze of stupefaction which held spellbound most of the denizens of

the Hill. But all were not so held--no conceivable emergency could take

the attention of the chief ultra-wave operator from his instruments.



"No, sir," Radio Center shot back. "It faded out and I couldn't recover

it. I put everything I've got behind a tracer on that beam, but haven't

been able to lift a single needle off the pin."



"And no wreckage of the vessel itself," Samms went on, half audibly.

"Either they have succeeded far beyond their wildest hopes or else ...

more probably...." He fell silent and switched off the plate. Were his

two friends, those intrepid scientists, alive and triumphant, or had

they gone to lengthen the list of victims of that man-killing

space-ship? Reason told him that they were gone. They must be gone, or

else his ultra-beams--energies of such unthinkable velocity of

propagation that man's most sensitive instruments had never been able

even to estimate it--would have held the ship's transmitter in spite of

any velocity attainable by any matter under any conceivable conditions.

The ship must have been disintegrated as soon as Rodebush released his

forces. And yet, had not the physicist dimly foreseen the possibility of

such an actual velocity--or had he? However, individuals could came and

could go, but Triplanetary went on. Samms squared his shoulders

unconsciously, and slowly, grimly, made his way back to his private

office.



He had scant time to mourn. Scarcely had he seated himself at his desk

when an emergency call came snapping in; a call of such import that his

secretary's usually calm voice trembled as she put it on his plate.



"Commissioner Hinkle is calling, sir," she announced. "Something

terrible is going on again, out toward Orion. Here he is," and there

appeared upon the screen the face of the Commissioner of Public Safety,

the commander of Triplanetary's every armed force--whether of land or of

water, of air or of empty space.



"They've come back, Samms!" the Commissioner rapped out, without

preliminary or greeting. "Four vessels gone--a freighter and a passenger

liner, with her escort of two heavy cruisers. All in Sector M; Dx about

151. I have ordered all traffic out of space for the duration of the

emergency, and since even our warships seem useless, every ship is

making for the nearest dock at maximum. How about that new flyer of

yours--got anything that will do us any good?" No one beyond the

"Hill's" shielding screens knew that the Boise had already been

launched.



"I don't know. We don't even know whether we have a super-ship or not,"

and Samms described briefly the beginning--and very probably the

ending--of the trial flight, concluding: "It looks bad, but if there was

any possible way of handling her, Rodebush and Cleveland did it. All our

tracers are negative yet, so nothing definite has...."



He broke off as a frantic call came in from the Pittsburgh station for

the Commissioner, a call which Samms both heard and saw.



"The city is being attacked!" came the urgent message. "We need all the

reinforcements you can send us!" and a picture of the beleaguered city

appeared in ghastly detail upon the screens of the observers; a view

being recorded from the air. It required only seconds for the

commissioner to order every available man and engine of war to the seat

of conflict; then, having done everything they could, Hinkle and Samms

stared in helpless, fascinated horror into their plates, watching the

scenes of carnage and destruction depicted there.



* * * * *



The Nevian vessel--the sister-ship, the craft which Costigan had seen in

mid-space as it hurtled earthward in response to Nerado's summons--hung

poised in full visibility, high above the metropolis. Scornful of the

pitiful weapons wielded by man she hung there, her sinister beauty of

line sharply defined against the cloudless sky. From her shining hull

there reached down a tenuous but rigid rod of crimson energy; a rod

which slowly swept hither and thither as the detectors of the amphibians

searched out the richest deposits of the precious iron for which the

inhuman visitors had come so far. Iron, once solid, now a viscous red

liquid, was sluggishly flowing in an ever-thickening stream up that

intangible crimson duct and into the capacious storage tanks of the

Nevian raider; and wherever that flaming beam went there went also ruin,

destruction, and death. Office buildings, skyscrapers towering

majestically in their architectural symmetry and beauty, collapsed into

heaps of debris as their steel skeletons were abstracted. Deep into the

ground the beam bored; flood, fire, and explosion following in its wake

as the mazes of underground piping disappeared. And the humanity of the

buildings died: instantaneously and painlessly, never knowing what

struck them, as the life-bearing iron of their bodies went to swell the

Nevian stream.



Pittsburgh's defenses had been feeble indeed. A few antiquated railway

rifles had hurled their shells upward in futile defiance, and had been

quietly absorbed. The district planes of Triplanetary, newly armed with

iron-driven ultra-beams, had assembled hurriedly and had attacked the

invader in formation, with but little more success. Under the impact of

their beams the stranger's screens had flared white, then poised ship

and flying squadron alike had been lost to view in a murkily opaque

shroud of crimson flame. The cloud had soon dissolved, and from the

place where the planes had been there had floated or crashed down a

litter of non-ferrous wreckage. And now the cone of space-ships from the

Buffalo base of Triplanetary was approaching Pittsburgh, hurling itself

toward the Nevian plunderer and toward known, gruesome and hopeless

defeat.



"Stop them, Hinkle!" Samms cried. "It's sheer slaughter! They haven't

got a thing--they aren't even equipped yet with the iron drive!"



"I know it," the commissioner groaned, "and Admiral Barnes knows it as

well as we do, but it can't be helped--wait a minute! The Washington

cone is reporting. They're as close as the other, and they have the new

armament. Philadelphia is close behind, and so is New York. Now perhaps

we can do something!"



The Buffalo flotilla slowed and stopped, and in a matter of minutes the

detachments from the other bases arrived. The cone was formed and

iron-driven vessels in the van, the old-type craft far in the rear, it

bore down upon the Nevian, vomiting from its hollow front a solid

cylinder of annihilation. Once more the screens of the Nevian flared

into brilliance, once more the red cloud of destruction was flung

abroad. But these vessels were not entirely defenseless. Their

iron-driven ultra-generators threw out screens of the Nevians' own

formulae, screens of prodigious power to which the energies of the

amphibians clung and at which they clawed and tore in baffled, wildly

coruscant displays of power unthinkable. For minutes the furious

conflict raged, while the inconceivable energy being dissipated by those

straining screens hurled itself in terribly destructive bolts of

lightning upon the city far beneath.



No battle of such incredible violence could long endure. Triplanetary's

ships were already exerting their utmost power, while the Nevians,

contemptuous of Solarian science, had not yet uncovered their full

strength. Thus the last desperate effort of mankind was proved futile as

the invaders forced their beams deeper and deeper into the overloaded,

defensive screens of the war-vessels; and one by one the supposedly

invincible space-ships of humanity dropped in horribly dismembered

wreckage upon the ruins of what had once been Pittsburgh.