The change of mind that had so affected
the Bree’s crew was not temporary; the
unreasoning, conditioned fear of height that had grown with them
from birth was gone. They still, however had normal reasoning
power; and in this part of their planet a fall of as much as half a
body’s length was nearly certain to be fatal even to their tough
organisms. Changed as they were, most of them felt uneasy as they
moored the Bree to the riverbank only a few
rods from the towering cliff that barred them from the grounded
rocket.
The Earthmen, watching in silence,
tried futilely to think of a way up the barrier. No rocket that the
expedition possessed could have lifted itself against even a
fraction of Mesklin’s gravity; the only one that had ever been
built able to do so was already aground on the planet. Even had the
craft been capable, no human or qualified non-human pilot could
have lived in the neighborhood; the only beings able to do that
could no more be taught to fly a rocket than a Bushman snatched
straight from the jungle.
“The journey simply isn’t as nearly
over as we thought.” Rosten, called to the screen room, analyzed
the situation rapidly. “There should be some way to the plateau or
farther slope—whichever is present—of that cliff. I’ll admit there
seems to be no way Barlennan and his people can get up; but there seems to be nothing preventing their going
around.” Lackland relayed this suggestion to the
captain.
“That is true,” the Mesklinite replied.
“There are, however, a number of difficulties. It is already
getting harder to procure food from the river; we are very far from
the sea. Also, we have no longer any idea of how far we may have to
travel, and that makes planning for food and all other
considerations nearly impossible. Have you prepared, or can you
prepare, maps with sufficient detail to let us plan our course
intelligently?”
“Good point. I’ll see what can be
done.” Lackland turned from the microphone to encounter several
worried frowns. “What’s the matter? Can’t we make a photographic
map as we did of the equatorial regions?”
“Certainly,” Rosten replied. “A map can
be made, possibly with a lot of
detail; but it’s going to be difficult. At the equator a rocket
could hold above a given point, at circular velocity, only six
hundred miles from the surface—right at the inner edge of the ring.
Here circular velocity won’t be enough, even if we could use it
conveniently. We’d have to use a hyperbolic orbit of some sort to
get short-range pictures without impossible fuel consumption; and
that would mean speeds relative to the surface of several hundred
miles a second. You can see what sort of pictures that would mean.
It looks as though the shots will have to be taken with long-focus
lenses, at extremely long range; and we can only hope that the
detail will suffice for Barlennan’s needs.”
“I hadn’t thought of that,” admitted
Lackland. “We can do it, though; and I don’t see any alternative in
any case. I suppose Barlennan could explore blind, but it would be
asking a lot of him.”
“Right. We’ll launch one of the rockets
and get to work.” Lackland gave the substance of this conversation
to Barlennan, who replied that he would stay where he was until the
information he needed was obtained.
“I could either go on upstream,
following the cliff around to the right, or leave the ship and the
river and follow to the left. Since I don’t know which is best from
the point of view of distance, we’ll wait. I’d rather go upstream,
of course; carrying food and radios will be no joke
otherwise.”
“All right. How is your food situation?
You said something about its being hard to get that far from the
ocean.”
“It’s scarcer, but the place is no
desert. We’ll get along for a time at least. If we ever have to go
overland we may miss you and your gun, though. This crossbow has
been nothing but a museum piece for nine tenths of the
trip.”
“Why do you keep the bow?”
“For just that reason—it’s a good
museum piece, and museums pay good prices. No one at home has ever
seen, or as far as I know even dreamed of, a weapon that works by
throwing things. You couldn’t spare one of your guns, could you? It
needn’t work, for that purpose.”
Lackland laughed. “I’m afraid not; we
have only one. We don’t expect to need it, but I don’t see how we
could explain giving it away.” Barlennan gave the equivalent of an
understanding nod, and turned back to his own duties. He had much
to bring up to date on the bowl that was his equivalent of a globe;
the Earthmen, throughout the trip, had been giving him bearing and
distance to land in all directions, so he was able to get most of
the shores of the two seas he had crossed onto the concave
map.
It was also necessary to see to the
food question; it was not, as he had told Lackland, really
pressing, but more work with the nets was going to be necessary
from now on. The river itself, now about two hundred yards wide,
appeared to contain fish enough for their present needs, but the
land was much less promising. Stony and bare, it ran a few yards
from one bank of the stream to end abruptly against the foot of the
cliff; from the other, a series of low hills succeeded each other
for mile after mile, presumably far beyond the distant horizon.
The rock of the escarpment’s face was polished glass-smooth, as
sometimes happens even on Earth to the rocks at the sliding edges
of a fault. Climbing it, even on Earth, would have required the
equipment and body weight of a By (on Mesklin, the fly would have
weighed too much). Vegetation was present, but not in any great
amount, and in the first fifty days of their stay no member of the
Bree’s crew saw any trace of land animal
life. Occasionally someone thought he saw motion, but each time it
turned out to be shadows cast by the whirling sun, now hidden from
them only by its periodic trips beyond the cliff. They were so near
the south pole that there was no visible change in the sun’s
altitude during the day.
For the Earthmen, the time was a little
more active. Four of the expedition, including Lackland, manned the
rocket and dropped planetward from the rapidly moving moon. From
their takeoff point the world looked rather like a pie plate with a
slight bulge in the center; the ring was simply a line of light,
but it stood out against the background of star-studded blackness
and exaggerated the flattening of the giant world.
As power was applied both to kill the
moon’s orbital velocity and bring them out of Mesklin’s equatorial
plane the picture changed. The ring showed for what it was, but
even the fact that it also had two divisions did not make the
system resemble that of Saturn. Mesklin’s flattening was far too
great for it to resemble anything but itself—a polar diameter of
less than twenty thousand miles compared to an equatorial one of
some forty-eight thousand has to be seen to be appreciated. All the
expedition members had seen it often enough now, but they still
found it fascinating.
The fall from the satellite’s orbit
gave the rocket a very high velocity, but, as Rosten had said, it
was not high enough. Power had to be used in addition; and although
the actual pass across the pole was made some thousands of miles
above the surface, it was still necessary for the photographer to
work rapidly. Three runs were actually made, each taking between
two and three minutes for the photography and many more for the
whipping journey around the planet. They made reasonably sure that
the world was presenting a different face to the sun each time, so
that the height of the cliff could be checked by shadow
measurements on all sides; then, with the photographs already fixed
and on one of the chart tables, the rocket spent more fuel swinging
its hyperbola into a wide arc that intercepted Toorey, and killing
speed so that too much acceleration would not be needed when they
got there. They could afford the extra time consumed by such a
maneuver; the mapping could proceed during the
journey.
Results, as usual with things
Mesklinite, were interesting if somewhat surprising. In this case,
the surprising fact was the size of the fragment of planetary crust
that seemed to have been thrust upward en bloc. It was shaped
rather like Greenland, some thirty-five hundred miles in length,
with the point aimed almost at the sea from which the Bree had come. The river leading to it, however,
looped widely around and actually contacted its edge at almost the
opposite end, in the middle of the broad end of the wedge. Its
height at the edges was incredibly uniform; shadow measurements
suggested that it might be a trifle higher at the point end than at
the Bree’s present position, but only
slightly. There were no sawtooth shadows to indicate gaps in the
wall.
Except at one point. One picture, and
one only, showed a blurring of the shadow that might be a gentler
slope. It was also in the broad end of the wedge, perhaps eight
hundred miles from where the ship now was. Still better, it was
upstream—and the river continued to hug the base of the cliff. It
looped outward at the point where the shadow break existed as
though detouring around the rubble pile of a collapsed slope, which
was very promising indeed. It meant that Barlennan had sixteen or
seventeen hundred miles to go instead of fifty, with half of it
overland; but even the overland part should not be overwhelmingly
difficult. Lackland said so, and was answered with the suggestion
that he make a more careful analysis of the surface over which his
small friend would have to travel. This, however, he put off until
after the landing, since there were better facilities at the
base.
Once there, microscopes and
densitometers in the hands of professional cartographers were a
little less encouraging, for the plateau itself seemed rather
rough. There was no evidence of rivers or any other specific cause
for the break in the wall that Lackland had detected; but the break
itself was amply confirmed. The densitometer indicated that the
center of the region was lower than the rim, so that it was
actually a gigantic shallow bowl; but its depth could not be
determined accurately, since there were no distinct shadows across
the inner portion. The analysts were quite sure, however, that its
deepest part was still well above the terrain beyond the
cliffs.
Rosten looked over the final results of
the work, and sniffed.
“I’m afraid that’s the best we can do
for him,” he said at last. “Personally, I wouldn’t have that
country on a bet even if I could live in it. Charlie, you may have
to figure out some way to give moral support; I don’t see how
anyone can give physical.”
“I’ve been doing my best all along.
It’s a nuisance having this crop up when we were so close to home
plate. I just hope he doesn’t give us up as a bad job this close to
the end; he still doesn’t believe everything we say, you know. I
wish someone could explain that high-horizon illusion to his—and
my—satisfaction; that might shake him out of the notion that his
world is a bowl, and our claim to come from another is at least
fifty percent superstition on our part.”
“You mean you don’t understand why it
looks higher?” one of the meteorologists exclaimed in a shocked
tone.
“Not in detail, though I realize the
air density has something to do with it.”
“But it’s simple enough—”
“Not for me.”
“It’s simple for anyone. You know how
the layer of hot air just above a road on a sunny day bends sky
light back upward at a slight angle, since the hot air is less
dense and the light travels faster in it; you see the sky
reflection and tend to interpret it as water. You get more
extensive mirages sometimes even on Earth, but they’re all based on
the same thing—a ‘lens’ or ‘prism’ of colder or hotter air refracts
the light. It’s the same here, except the gravity is responsible;
even hydrogen decreases rapidly in density as you go up from
Mesklin’s surface. The low temperature helps, of
course.”
“All right if you say so; I’m not a—”
Lackland got no chance to finish his remark; Rosten cut in abruptly
and grimly.
“Just how fast does this density drop
off with altitude?” The meteorologist drew a slide rule from his
pocket and manipulated it silently for a moment.
“Very roughly, assuming a mean
temperature of minus one-sixty, it would drop to about one percent
of its surface density at around fifteen or sixteen hundred feet.”
A general stunned silence followed his words.
“And—how far would it have dropped
at—say—three hundred feet?” Rosten finally
managed to get the question out. The answer came after a moment of
silent lip movement.
“Again very roughly, seventy or eighty
percent—probably rather more.”
Rosten drummed his fingers on the table
for a minute or two, his eyes following their motions; then he
looked around at the other faces. All were looking back at him
silently.
“I suppose no one can suggest a bright
way out of this one; or does someone really hope that Barlennan’s
people can live and work under an air pressure that compares to
their normal one about as that at forty or fifty thousand feet does
to ours?”
“I’m not sure.” Lackland frowned in
concentration, and Rosten brightened a trifle. “There was some
reference a long time ago to his staying under water—excuse me,
under methane—for quite a while, and swimming considerable
distances. You remember those river-dwellers must have moved the
Bree by doing just that. If it’s the
equivalent of holding breath or a storage system such as our whales
use, it won’t do us any good; but if he can actually get a fair
part of the hydrogen he needs from what’s in solution in Mesklin’s
rivers and seas, there might be some hope.” Rosten thought for a
moment longer.
“All right. Get your little friend on
the radio and find out all he knows himself about this ability of
his. Rick, look up or find out somehow the solubility of hydrogen
in methane at eight atmospheres pressure and temperatures between
minus one forty-five and one eighty-five Centigrade. Dave, put that
slide rule back in your pocket and get to a calculator; get as
precise a value of the hydrogen density on that cliff top as
physics, chemistry, math, and the gods of good weather men will let
you. Incidentally, didn’t you say there was a drop of as much as
three atmospheres in the center of some of those tropical
hurricanes?
Charlie, find out from Barlennan whether and how much he and his
men felt that. Let’s go.” The conference broke up, its members
scattering to their various tasks. Rosten remained in the screen
room with Lackland, listening to his conversation with the
Mesklinite far below.
Barlennan agreed that he could swim
below the surface for long periods without trouble; but he had no
idea how he did it. He did not breathe anyway, and did not
experience any feeling comparable to the human sense of
strangulation when he submerged. If he stayed too long and was too
active the effect was rather similar to sleepiness, as nearly as he
could describe it; if he actually lost consciousness, however, it
stopped there; he could be pulled out and revived as much later as
anyone cared as long as he didn’t starve in the meantime. Evidently
there was enough hydrogen in solution in Mesklin’s seas to keep him
alive, but not for normal activity. Rosten brightened
visibly.
“There is no discomfort of the sort you
suggest in the middle of the worst storms I have ever experienced,”
the captain went on. “Certainly no one was too weak to hold on
during that one which cast us on the island of the gliders—though
we were in its center for only two or three minutes, of course.
What is your trouble? I do not understand what all these questions
are leading to.” Lackland looked to his chief for permission, and
received a silent nod of affirmation.
“We have found that the air on top of
this cliff, where our rocket is standing, is very much thinner than
at the bottom. We doubt seriously that it will be dense enough to
keep you and your people going.”
“But that is only three hundred feet;
why should it change that much in such a short
distance?”
“It’s that gravity of yours; I’m afraid
it would take too long to explain why, but on any world the air
gets thinner as you go higher, and the more the gravity the faster
that change. On your world the conditions are a trifle
extreme.”
“But where is the air at what you would
call normal for this world?”
“We assume at sea level; all our
measures are usually made from that reference.”
Barlennan was thoughtful for a little
while. “That seems silly; I should think you’d want a level that
stayed put to measure from. Our seas go up and down hundreds of
feet each year—and I’ve never noticed any particular change in the
air.”
“I don’t suppose you would, for several
reasons; the principal one is that you would be at sea level as
long as you were aboard the Bree, and
therefore at the bottom of the atmosphere in any case. Perhaps it
would help you to think of this as a question of what weight of air
is above you and what weight below.”
“Then there is still a catch,” the
captain replied. “Our cities do not follow the seas down; they are
usually on the seacoast in spring and anywhere from
two hundred miles to two thousand inland by fall. The slope of the
land is very gentle, of course, but I am sure they are fully three
hundred feet above sea level at that time.” Lackland and Rosten
stared silently at each other for a moment; then the latter
spoke.
“But you’re a lot farther from the pole
in your country—but no, that’s quibbling. Even if gravity were only
a third as great you’d be experiencing tremendous pressure changes.
Maybe we’ve been taking nova precautions for a red dwarf.” He
paused for a moment, but the Mesklinite made no answer. “Would you
be willing, then, Barlennan, to make at least an attempt to get up
to the plateau? We certainly will not insist on your going on if it
proves too hard on your physical make-up, but you already know its
importance to us.”
“Of course I will; we’ve come this far,
and have no real reason to suppose what’s coming will be any worse
than what’s past. Also, I want …” He paused briefly, and went on in
another vein. “Have you yet found any way of getting up there, or
is your question still hypothetical?” Lackland resumed the human
end of the conversation.
“We have found what looks like a way,
about eight hundred miles upstream from your present position. We
can’t be sure you can climb it; it resembles a rock fall of very
moderate slope, but we can’t tell from our distance how big the
rocks may be. If you can’t get up there, though, I’m afraid you
just can’t get up at all. The cliff seems to be vertical all around
the plateau except for that one point.”
“Very well, we will head upstream. I
don’t like the idea of climbing even small rocks here, but we’ll do
our best. Perhaps you will be able to give suggestions when you can
see the way through the vision sets.”
“It will take you a long time to get
there, I’m afraid.”
“Not too long; for some reason there is
a wind along the cliff in the direction we wish to go. It has not
changed in direction or strength since we arrived several score
days ago. It is not as strong as the usual sea wind, but it will
certainly pull the Bree against the current—if the river does not
grow too much swifter.”
“This one does not grow too much
narrower, at any rate, as far as you will be going. If it speeds
up, it must be because it grows shallower. All we can say to that
is that there was no sign of rapids on any of the
pictures.”
“Very well, Charles. We will start when
the hunting parties are all in.”
One by one the parties came back to the
ship, all with some food but none with anything interesting to
report. The rolling country extended as far in all directions as
anyone had gone; animals were small, streams scarce, and vegetation
sparse except around the few springs. Morale was a trifle low, but
it improved with the news that the Bree was
about to travel again. The few articles of equipment that had been
disembarked were quickly reloaded on the rafts,
and the ship pushed out into the stream. For a moment she drifted
seaward, while the sails were being set; then they filled with the
strangely steady wind and she bore up against the current, forging
slowly but steadily into unknown areas of the hugest planet man had
yet attempted to explore.