the other dully glowing an equally invisible red, at the touch of which body temperature
soared to lethal heights and foliage burst cracklingly into spontaneous flame.
In their massed hundreds the savages dropped where they stood, life rived away
by the torturing ultra-violet, burned away by the blast of pure heat, or consumed by the
conflagrations that raged instantly wherever that wide-sweeping fan encountered
combustible material. In the face of power supernatural they lost all thought of attack or
of conquest, and sought only and madly to escape. Weapons were thrown away, the
catapults were abandoned, and, every man for himself, the mob fled in wildest disorder,
each striving to put as much distance as possible between himself and that place of
dread mystery, the waterfall.
“Well, I guess that’ll hold ’em for a while,” Stevens dropped their craft back into
its original quarters in the canyon. “Whether they ever believed before that this falls was
inhabited by devils or not, they think so now. I’ll bet that it’ll be six hundred Jovian years
before any of them ever come within a hundred kilometers of it again. I’m glad of it, too,
because they’ll let our power plant alone now. Well, let’s get going—we’ve got to make
things hum for a while!”
“Why all the rush ? You just said that we have scared them away for good.”
“The savages, yes, but not those others. We’ve just turned loose enough
radiation to affect detectors all over the system, and it’s up to us to get this beam
projector set up, get away from here, and get our power shut off before they can trace
us. Snap it up, ace!”
The transmitter unit was installed at the converters, the cable was torn out; and
having broken the last material link between it and Ganymede, Stevens hurled the
Forlorn Hope out into space, using the highest acceleration Nadia could endure. Hour
after hour the massive wedge of steel bored outward, away from Jupiter; hour after hour
Stevens’ anxious eyes scanned his instruments; hour after hour hope mounted and
relief took the place of anxiety as the screens remained blank throughout every inquiring
thrust into the empty ether.
CHAPTER 5 Cantrell’s Comet
Far out in space, Jupiter a tiny moon and its satellites mere pin-points of light, Stevens
turned to his companion with a grin.
“Well, Nadia, my ex-groundgripper, here’s where we turn spacehounds again.
Hope you like it better this time, because I’m afraid that we’ll have to stay weightless ‘for
quite a while.” He slowly throttled down the mighty flow of power, and watched the
conflicting emotions play over Nadia’s face in her purely personal battle against the
sickening sensations caused by the decrease in their acceleration.
“I’m sorry, sweetheart.” His grin disappeared. “Wish I could take it for you, but. .
.”
“But there are times when we’ve got to fight, our own battles and bury our own
dead,” she interrupted, gamely. “Cut off the rest of that power! I’m not going to be sick—
I won’t be a—what do you spacehounds call us poor earth-bound dubs who can’t stand
weightlessness—weight-fiends, isn’t it?”
“Yes; but you aren’t . . .”
“I know I’m not, and I’m not going to be one, either! I’m all x, Steve—it’s not so
bad now, really. I held myself together that time, anyway, and I feel lots better now.
Have you found Cantrell’s Comet yet ? And why so sure all of a sudden that they can’t
find us ? That power beam still connects us to Ganymede, doesn’t it ? Maybe they can
trace it.”
“At-a-girl, ace!” he cheered. “I’ll tell the world you’re no weight-fiend—you’re a
spacehound right. Most first-trippers, at this stage of the game, wouldn’t be caring a
whoop whether school kept or not, and here you’re taking an interest in all kinds of
things already. You’ll do, girl of my heart—no fooling!”
“Maybe,1 and maybe you’re trying to kid somebody,” she returned, eying him
intently. “Or maybe you just don’t want to answer those questions I asked you a minute
ago.”
“No, that’s straight data, right on zero clear across the panel,” he assured her.
“And as for your questions, they’re easy. No, I haven’t looked for the comet yet,
because we’ll have to drift for a couple of days before we’ll be anywhere near where I
think it is. No, they can’t trace us, because there is now nothing to trace, unless they
can detect the slight power we are using in our lights and so on—which possibility is
vanishingly small. Potentially, our beam still exists, but since we are drawing no power,
it has no actual present existence. See?”
“Uh-uh,” she dissented. “I can’t say that I .can quite understand how a beam can
exist potentially and yet not be there actually enough to trace. Why, a thing has to be
actual or not exist at all—you can’t possibly have something that is nothing. It doesn’t
make sense. But lay off of those integrations of yours, please,” as Stevens began to
draw a diagram. “You know that your brand of math is over my head like a circus tent,
so we’ll let it lay. I’ll take your word for it, Steve—if you’re satisfied, it’s all x with me.”
“I think I can straighten you out a little, by analogy. Here’s a rough sketch of a
cylinder, with its shade and shadow. You’ve had descriptive geometry, of course, and so
know that a shadow, being simply a projection of a material object upon a plane, is a
two-dimensional thing—or rather, a two-dimensional concept. Now take the shade,
which is, of course, this entire figure here, between the cylinder casting the shadow and
the plane of projection. You simply imagine that there is a point source of light at your
point of projection: it isn’t really there. The shade, then, of which I am drawing a picture,
has only a potential existence. You know exactly where it is, you can draw it, you can
define it, compute it, and work with it — but still it doesn’t exist; there is absolutely
nothing to differentiate it from any other volume of air, and it cannot be detected by any
physical or mechanical means. If, however, you place a light at the point of projection,
the shade becomes actual and can be detected optically. By a sufficient stretch of the
imagination you might compare our beam to that shade. When we turn our power on the
beam is actual; it is a stream of tangible force, and as such can be detected electrically.
When our switches here are open, however, it exists only potentially. There is no motion
in the ether, nothing whatever to indicate that a beam ever had actually existed there.
With me?”
“Floundering pretty badly, but I see it after a fashion. You physicists are peculiar
freaks—where we ordinary mortals see actual, solid, heavy objects, you see only empty
space with a few electrons and things floating around in it; and yet where we see only
empty space, you can see things ‘potentially’ that may never exist at all. You’ll be the
death of me yet, Steve! But I’m wasting a lot of time. What do we do now ?”
“We get busy on the big tube. You might warm up the annealing oven and melt
me that pot of glass, while I get busy on the filament supports, plate brackets, and so
on.” Both fell to work with a will, and hours passed rapidly and almost silently, so intent
was each upon his own tasks.
“All x, Steve,” Nadia broke the long silence. “The pyrometer’s on the red, and the
oven’s hot,” and the man left his bench. Taking up a long paddle and an even longer
blow-pipe, he skimmed the melt to a dazzlingly bright surface and deftly formed a
bubble.
“I just love to talk at you when you’ve got your mouth full of a blowpipe.” Nadia
eyed him impishly and tucked her feet beneath her, poised weightless as she was. “I’ve
got you foul now—I can say anything I want to, and you can’t talk back, because your
bubble will lose its shape if you do. Oh, isn’t that a beauty! I never saw you blow
anything that big before,” and she fell silent, watching intently.
Slowly there was being drawn from the pot a huge, tapering bulb of hot,
glistening glass, its cross-section at the molten surface varying as Stevens changed the
rate of draw or the volume of air blown through the pipe. Soon that section narrowed
sharply. The glass-blower waved his hand and Nadia severed the form neatly with a
glowing wire, just above the fluid surface of the glass remaining in the pot. Pendant from
the blowpipe the bulb was placed over the hot-bench, where Stevens, now begoggled,
begloved, and armed with a welding torch, proceeded to embellish it with sundry necks,
side-tubes, supports and other attachments of peculiar pattern. Finally the partially-