X.

"Dick!" Dorothy shrieked, flashing to Seaton's side; and, abandoning

his fruitless speculations, he turned to confront two indescribable,

yet vaguely recognizable, entities who had floated effortlessly into

the control room of the _Skylark_. Large they were, and black--a dull,

lusterless black--and each was possessed of four huge, bright lenses

which apparently were eyes. "Dick! What are they, anyway?"

"Life, probably; the intelligent, four-dimensional life that Mart fully

expected to find here," Seaton answered. "I'll see if I can't send them

a thought."

Staring directly into those expressionless lenses the man sent out wave

after wave of friendly thought, without result or reaction. He then

turned on the power of the mechanical educator and donned a headset,

extending another toward one of the weird visitors and indicating as

clearly as he could by signs that it was to be placed back of the

outlandish eyes. Nothing happened, however, and Seaton snatched off the

useless phones.

"Might have known they wouldn't work!" he snorted. "Electricity! Too

slow--and those tubes probably won't be hot in less than ten years

of this hypertime, besides. Probably wouldn't have been any good,

anyway--their minds would of course be four-dimensional, and ours most

distinctly are not. There may be some point--or rather, plane--of

contact between their minds and ours, but I doubt it. They don't act

warlike, though; we'll simply watch them a while and see what they do."

But if, as Seaton had said, the intruders did not seem inimical,

neither were they friendly. If any emotion at all affected them, it was

apparently nothing more nor less than curiosity. They floated about,

gliding here and there, their great eyes now close to this article,

now that; until at last they floated _past_ the arenak wall of the

spherical space ship and disappeared.

Seaton turned quickly to his wife, ready to minister again to

overstrained nerves, but much to his surprise he found Dorothy calm and

intensely interested.

"Funny-looking things, weren't they, Dick?" she asked animatedly. "They

looked just like highly magnified chess knights with four hands; or

like those funny little sea horses they have in the aquarium, only on a

larger scale. Were those propellers they had instead of tails natural

or artificial--could you tell?"

"Huh? What're you talking about? I didn't see any such details as

that!" Seaton exclaimed.

"I couldn't, either, really," Dorothy explained, "until after I found

out how to look at them. I don't know whether my method would appeal

to a strictly scientific mind or not. I can't understand any of this

fourth-dimensional, mathematical stuff of yours and Martin's, anyway,

so when I want to see anything out here I just pretend that the

fourth dimension isn't there at all. I just look at what you call the

three-dimensional surface and it looks all right. When I look at you

that way, for instance, you look like my own Dick, instead of like a

cubist's four-dimensional nightmare."

"You have hit it, Dorothy." Crane had been visualizing four-dimensional

objects as three-dimensional while she was speaking. "That is probably

the only way in which we can really perceive hyperthings at all."

"It _does_ work, at that!" Seaton exclaimed. "Congratulations, Dot;

you've made a contribution to science--but say, what's coming off now?

We're going somewhere."

* * * * *

For the _Skylark_, which had been floating freely in space--a motion

which the senses of the wanderers had long since ceased to interpret

as a sensation of falling--had been given an acceleration. Only a

slight acceleration, barely enough to make the floor of the control

room seem "down," but any acceleration at all in such circumstances was

to the scientists cause for grave concern.

"Nongravitational, of course, or we couldn't feel it--it'd affect

everything about the ship alike. What's the answer, Mart, if any?"

Seaton demanded. "Suppose that they've taken hold of us with a tractor

ray and are taking us for a ride?"

"It would appear that way. I wonder if the visiplates are still

practical?" Crane moved over to number one visiplate and turned it in

every direction. Nothing was visible in the abysmal, all-engulfing,

almost palpable darkness of the absolute black outside the hull of the

vessel.

"It wouldn't work, hardly," Seaton commented. "Look at our time

here--we must be 'way beyond light. I doubt if we could see anything,

even if we had a sixth-order projector--which of course we haven't."

"But how about our light inside here, then?" asked Margaret. "The lamps

are burning, and we can see things."

"I don't know, Peg," Seaton replied. "All this stuff is 'way past me.

Maybe it's because the lights are traveling with us--no, that's out.

Probably, as I intimated before, we aren't seeing things at all--just

feeling them, some way or other. That must be it, I think--it's sure

that the light-waves from those lamps are almost perfectly stationary,

as far as we're concerned."

"Oh, there's something!" Dorothy called. She had remained at the

visiplate, staring into the impenetrable darkness. "See, it just

flashed on! We're falling toward ground of some kind. It doesn't look

like any planet I ever saw before, either--it's perfectly endless and

it's perfectly flat."

The others rushed to the plates and saw, instead of the utter

blackness of a moment before, an infinite expanse of level, uncurving

hyperland. Though so distant from it that any planetary curvature

should have been evident, they could perceive no such curvature. Flat

that land was, and sunless, but apparently self-luminous; glowing with

a strong, somewhat hazy, violet light. And now they could also see

the craft which had been towing them. It was a lozenge-shaped affair,

glowing fiercely with the peculiarly livid "light" of the hyperplanet;

and was now apparently exerting its maximum tractive effort in a vain

attempt to hold the prodigious mass of _Skylark Two_ against the

seemingly slight force of gravitation.

"Must be some kind of hyperlight that we're seeing by," Seaton

cogitated. "Must be sixth or seventh-order velocity, at least, or we'd

be--"

"Never mind the light or our seeing things!" Dorothy interrupted. "We

are falling, and we shall probably hit hard. Can't you do something

about it?"

"Afraid not, Kitten." He grinned at her. "But I'll try it--Nope,

everything's dead. No power, no control, no nothing, and there won't be

until we snap back where we belong. But don't worry about a crash. Even

if that ground is solid enough to crash us, and I don't think it is,

everything out here, including gravity, seems to be so feeble that it

won't hurt us any."

Scarcely had he finished speaking when the _Skylark_ struck--or,

rather, floated gently downward into the ground. For, slight as was

the force of gravitation, and partially counteracted as well by the

pull of the towing vessel, the arenak globe did not even pause as

it encountered the apparently solid rock of the planet's surface.

That rock billowed away upon all sides as the _Skylark_ sank into it

and through it, to come to a halt only after her mass had driven a

vertical, smooth-sided well some hundreds of feet in depth.

Even though the Osnomian metal had been rendered much less dense than

normal by its extrusion and expansion into the fourth dimension, yet it

was still so much denser than the unknown material of the hyperplanet

that it sank into that planet's rocky soil as a bullet sinks into thick

jelly.

"Well, that's that!" Seaton declared. "Thinness and tenuosity, as well

as feebleness, seem to be characteristics of this hypermaterial. Now

we'll camp here peacefully for a while. Before they succeed in digging

us out--if they try it, which they probably will--we'll be gone."

* * * * *

Again, however, the venturesome and impetuous chemist was wrong. Feeble

the hypermen were, and tenuous, but their curiosity was whetted even

sharper than before. Derricks were rigged, and slings; but even before

the task of hoisting the _Skylark_ to the surface of the planet was

begun, two of the peculiar denizens of the hyperworld were swimming

down through the atmosphere of the four-dimensional well at whose

bottom the Earth vessel lay. Past the arenak wall of the cruiser they

dropped, and into the control room they floated.

"But I do not understand it at all, Dick," Crane had been arguing.

"Postulating the existence of a three-dimensional object in

four-dimensional space, a four-dimensional being could of course

enter it at will, as your fingers entered that tobacco can. But since

all objects here are in fact and of necessity four-dimensional, that

condition alone should bar any such proceeding. Therefore, since you

actually _did_ take the contents out of that can without opening it,

and since our recent visitors actually _did_ enter and leave our

vessel at will, I can only conclude that we must still be essentially

three-dimensional in nature, even though constrained temporarily to

occupy four-dimensional space."

"Say, Mart, that's a thought! You're still the champion

ground-and-lofty thinker of the universe, aren't you? That explains

a lot of things I've been worrying myself black in the face about. I

think I can explain it, too, by analogy. Imagine a two-dimensional man,

one centimeter wide and ten or twelve centimeters long; the typical

flatlander of the classical dimensional explanations. There he is, in

a plane, happy as a clam and perfectly at home. Then some force takes

him by one end and rolls him up into a spiral, or sort of semisolid

cylinder, one centimeter long. He won't know what to make of it, but

in reality he'll be a two-dimensional man occupying three-dimensional

space.

"Now imagine further that we can see him, which of course is a pretty

tall order, but necessary since this is a very rough analogy. We

wouldn't know what to make of him, either, would we? Doesn't that

square up with what we're going through now? We'd think that such a

thing was quite a curiosity and want to find out about it, wouldn't we?

That, I think, explains the whole thing, both our sensations and the

actions of those sea horses--huh! Here they are again. Welcome to our

city, strangers!"

But the intruders made no sign of understanding the message. They did

not, could not, understand.

The human beings, now using Dorothy's happily discovered method of

dimensional reduction, saw that the hypermen did indeed somewhat

resemble overgrown sea horses--the hippocampus of Earthly zoölogy--but

sea horses each equipped with a writhing, spinning, air-propeller tail

and with four long and sinuous arms, terminating in many dexterous and

prehensile fingers.

[Illustration: _Using Dorothy's method of dimensional reduction, Seaton

and the Cranes saw that the hypermen did indeed somewhat resemble

overgrown sea horses._]

Each of those hands held a grappling trident; a peculiar,

four-dimensional hyperforceps whose insulated, interlocking teeth

were apparently electrodes--conductors of some hyperequivalent of our

Earthly electricity. With unmoved, expressionless "faces" the two

visitors floated about the control room, while Seaton and Crane sent

out wave after wave of friendly thought and made signs of friendship in

all the various pantomimic languages at their command.

"Look out, Mart, they're coming this way! I don't want to start

anything hostile, but I don't particularly like the looks of those

toad-stabbers of theirs, and if they start any funny business with them

maybe we'd better wring their fishy little necks!"

But there was to be no neck-wringing--then. Slight of strength the

hypermen were, and of but little greater density than the thin air

through which they floated so easily; but they had no need of physical

strength--then.

Four tridents shot out, and in a monstrously obscure fashion reached

_past_ clothing, skin, and ribs; seizing upon and holding firmly, but

painlessly and gently, the vital nervous centers of the human bodies.

Seaton tried to leap to the attack, but even his quickness was of

no avail--even before he moved, a wave of intolerable agony surged

throughout his being, ceasing only and completely when he relaxed,

relinquishing his pugnacious attempt. Shiro, leaping from the galley

with cleaver upraised, was similarly impaled and similarly subdued.

Then a hoisting platform appeared, and Seaton and Margaret were forced

to board it. They had no choice; the first tensing of the muscles to

resist the will of the hyperman was quelled instantly by a blast of

such intolerable torture that no human body could possibly defy it for

even the slightest perceptible instant of time.

"Take it easy, Dot--Mart," Seaton spoke rapidly as the hoist started

upward. "Do whatever they say--no use taking much of that stuff--until

Peg and I get back. We'll get back, too, believe me! They'll _have_

to take these meat hooks out of us sometime, and when they do they'll

think a cyclone has broken loose."