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Transcriber's Note:

    This etext was produced from _Analog_ August 1962. Extensive
    research did not uncover any evidence that the U.S. copyright on
    this publication was renewed. Minor spelling and typographical
    errors have been corrected without note. Subscript characters are
    shown within {braces}.




The Bramble Bush

 Usually, if a man's gotten into bad trouble
 by getting into something,
 he's a fool to go back. But there are times ...

by Randall Garrett

Illustrated by Schelling


    _There was a man in our town,
    And he was wond'rous wise;
    He jumped into a bramble bush,
    And scratch'd out both his eyes!_
                          --Old Nursery Rhyme


Peter de Hooch was dreaming that the moon had blown up when he awakened.
The room was dark except for the glowing night-light near the door, and
he sat up trying to separate the dream from reality. He focused his eyes
on the glow-plate. What had wakened him? Something had, he was sure, but
there didn't seem to be anything out of the ordinary now.

The explosion in his dream had seemed extraordinarily realistic. He
could still remember vividly the vibration and the _cr-r-r-ump!_ of the
noise. But there was no sign of what might have caused the dream
sequence.

Maybe something fell, he thought. He swung his legs off his bed and
padded barefoot over to the light switch. He was so used to walking
under the light lunar gravity that he was no longer conscious of it. He
pressed the switch, and the room was suddenly flooded with light. He
looked around.

Everything was in place, apparently. There was nothing on the floor that
shouldn't be there. The books were all in their places in the bookshelf.
The stuff on his desk seemed undisturbed.

The only thing that wasn't as it should be was the picture on the wall.
It was a reproduction of a painting by Pieter de Hooch, which he had
always liked, aside from the fact that he had been named after the
seventeenth-century Dutch artist. The picture was slightly askew on the
wall.

He was sleepily trying to figure out the significance of that when the
phone sounded. He walked over and picked it up. "Yeah?"

"Guz? Guz? Get over here quick!" Sam Willows' voice came excitedly from
the instrument.

"Whatsamatter, Puss?" he asked blearily.

"Number Two just blew! We need help, Guz! Fast!"

"I'm on my way!" de Hooch said.

"Take C corridor," Willows warned. "A and B caved in, and the bulkheads
have dropped. Make it snappy!"

"I'm gone already," de Hooch said, dropping the phone back into place.

He grabbed his vacuum suit from its hanger and got into it as though his
own room had already sprung an air leak.

_Number Two has blown!_ he thought. That would be the one that Ferguson
and Metty were working on. What had they been cooking? He couldn't
remember right off the bat. Something touchy, he thought; something
pretty hot.

But that wouldn't cause an atomic reactor to blow. It obviously hadn't
been a nuclear blow-up of any proportions, or he wouldn't be here now,
zipping up the front of his vac suit. Still, it had been powerful enough
to shake the lunar crust a little or he wouldn't have been wakened by
the blast.

These new reactors could get out a lot more power, and they could do a
lot more than the old ones could, but they weren't as safe as the old
heavy-metal reactors, by a long shot. None had blown up yet--quite--but
there was still the chance. That's why they were built on Luna instead
of on Earth. Considering what they could do, de Hooch often felt that it
would be safer if they were built out on some nice, safe
asteroid--preferably one in the Jovian Trojan sector.

He clamped his fishbowl on tight, opened the door, and sprinted toward
Corridor C.

The trouble with the Ditmars-Horst reactor was that it lacked any
automatic negative-feedback system. If a D-H decided to go wild, it went
wild. Fortunately, that rarely happened. The safe limits for reactions
were quite wide--wider, usually, than the reaction limits themselves, so
that there was always a margin of safety. And within the limits, a
nicety of control existed that made nucleonics almost an esoteric branch
of chemistry. Cookbook chemistry, practically.

Want deuterium? Recipe: To 1.00813 gms. purest Hydrogen-1 add, slowly
and with care, 1.00896 gms. fine-grade neutrons. Cook until well done in
a Ditmars-Horst reactor. Yield: 2.01471 gms. rare old deuterium plus
some two million million million ergs of raw energy. Now you are cooking
with gas!

All you had to do was keep the reaction going at a slow enough rate so
that the energy could be bled off, and there was nothing to worry about.
Usually. But control of the feebleizer fields still wasn't perfect,
because the fields that enfeebled the reactions and made them easy to
control weren't yet too well understood.

       *       *       *

Peter de Hooch turned into Corridor C and kept on running. There was
plenty of air still in this corridor, and there was apparently little
likelihood of his needing his vac suit. But on the moon nobody responds
to an emergency call without a vac suit.

He was troubled about Corridors A and B. The explosion must have been
pretty violent to have sealed off two of the four corridors leading from
the living quarters to the reaction labs. Two corridors went directly to
one of the reactors, two went directly to the second. Two more connected
the reactor labs themselves, putting the labs and the living quarters at
the corners of an equilateral triangle. (Peter had never been able to
figure out why A and B corridors led to Reactor Two, while C and D led
to Reactor One. Logically, he thought, it should have been the other way
around. Oh, well.)

Going down C meant that he'd have to get to Reactor Two the long way
around.

What had the damage been? he asked himself. Had anyone been hurt? Or
killed? He pushed the questions out of his mind. There was no point in
speculating. He'd have the information soon enough.

He took the cutoff to the left, at a sixty-degree angle to Corridor C,
which led him directly to Corridor E, by-passing Reactor One. He noticed
as he went by that the operations lamp was out. Nobody was working with
Reactor One.

As he pounded on down the empty corridor, he suddenly realized that he
hadn't seen anyone else running with him. There were five other men in
the reactor station, and--so far--he had seen no one. He knew where
Willows was, but where were Ferguson, Metty, Laynard, and Quillan? He
pushed those questions out of his mind, too, for the time being.

A head popped out of the door at the far end of the corridor.

"Guz! _Hurry_, Guz!"

De Hooch didn't bother to answer Willows. He was short of breath as it
was. He knew, besides, that no answer was expected. He had known Willows
for years, and knew how he thought. It was Willows who had first tagged
de Hooch with that silly nickname, "Guzzle". Not because Peter was such
a heavy drinker--although he could hold it like a gentleman--but because
he had thought "Guzzle" de Hooch was so uproariously funny. "Nobody
likes a guzzle as well as de Hooch," he'd say, with an idiot grin. As a
result, everybody called Peter "Guz" now.

The head had vanished back into the control room of Reactor Two. De
Hooch kept on running, his breath rasping loudly in the confines of the
fishbowl helmet. Running four hundred yards isn't the easiest thing in
the world, even if a man is in good physical condition. There was less
weight to contend with, but the mass that had to be pushed along
remained the same. The notion that running on Luna was an effortless
breeze was one that only Earthhuggers clung to.

He ran into the control room and stopped, panting heavily. "What ...
happened?"

Sam Willows' normally handsome face looked drawn. "Something went wrong.
I don't know what. I was finishing up with Reactor One when I heard the
explosion. They are both"--he gestured toward the reactor--"both in
there."

"Still alive?"

"I think so. One of 'em, anyway. Take a look."

De Hooch went over to the periscope and put his eyes to the binoculars.
He could see two figures in heavy, dull-gray radiation-proof suits. They
were lying flat on the floor, and neither was moving. De Hooch said as
much.

"The one on the left was moving his arm--just a little," Willows said.
"I'll swear he was."

Something in the man's voice made de Hooch turn his head away from the
periscope's eyepieces. Willows' face was gray, and a thin film of greasy
perspiration reflected the light from the overhead plates. The man was
on the verge of panic.

"Calm down, Puss," de Hooch said gently. "Where's Quillan and Laynard?"

"They're in their rooms," Willows said in a tight voice. "Trapped. The
bulkheads have closed 'em off in A. No air in the corridor. We'll have
to dig 'em out. I called 'em both on the phone. They're all right, but
they're trapped."

"Did you call Base?"

"Yes. They haven't got a ship. They sent three moon-cats, though. They
ought to be here by morning."

De Hooch looked up at the chronometer on the wall. Oh one twelve,
Greenwich time. "Morning" meant any time between eight and noon; the
position of the sun up on the surface had nothing to do with Lunar time.
As a matter of fact, there was a full Earth shining at the moment, which
meant that it wouldn't be dawn on the surface for a week yet.

"If the cats from Base get here by noon, we'll be O.K., won't we?" de
Hooch asked.

"Look at the instruments," Willows said.

De Hooch ran a practiced eye over the console and swallowed. "What were
they running?"

"Mercury 203," Willows said. "Half-life forty-six point five days. Beta
and gamma emitter. Converts to Thallium 203, stable."

"What did they want with a kilogram of the stuff?"

"Special order. Shipment to Earth for some reason."

"Have you checked the end-point? She's building up fast."

"No. No. I haven't." He wet his lips with the tip of his tongue.

"Check it," said de Hooch. "Do any of the controls work?"

"I don't know. I didn't want to fiddle with them."

"You start giving them a rundown. I'm going to get into a suit and go
pull those two out of there--if they're still alive." He opened the
locker and took his radiation-proof suit out. He checked it over
carefully and began shucking his vac suit.

       *       *       *       *       *

A few minutes delay in getting to the men in the reactor's anteroom
didn't matter much. If they hadn't been killed outright, and were still
alive, they would probably live a good deal longer. The shells of the
radiation suits didn't look damaged, and the instruments indicated very
little radiation in the room. Whatever it was that had exploded had done
most of its damage at the other end of the reactor. Evidently, a fissure
had been opened to the surface, forty feet above--a fissure big enough
to let all the air out of A and B corridors, and activate the automatic
bulkheads to seal off the airless section.

What troubled him was Willows. If he hadn't known the man so well, de
Hooch would have verbally blasted him where he stood.

His reaction to trouble had been typical. De Hooch had already seen
Willows in trouble three times, and each time, the reaction had been the
same: near panic. Every time, his first thought had been to scream for
help rather than to do anything himself. Almost anyone else would have
made one call and then climbed into a radiation suit to get Ferguson and
Metty out of the anteroom. There was certainly no apparent immediate
danger. But all that Willows had done was yell for someone to come and
do his thinking and acting for him. He had called Base; he had called de
Hooch; he had called Quillan and Laynard. But he hadn't done anything
else.

Now he had to be handled with kid gloves. If de Hooch didn't act calm,
if he didn't go about things just right, Willows might very likely go
over the line into total panic. As long as he had someone to depend on,
he'd be all right, and de Hooch didn't want to lose the only help he had
right now.

"Fermium 256," said Willows in a tight, flat voice.

"What?" de Hooch asked calmly.

"Fermium 256," Willows repeated. "That's what the stuff is going to
start building towards. Spontaneous fission. Half-life of three hours."
He took a deep breath. "The reactor won't be able to contain it. We
haven't got that kind of bleed-off control."

"No," de Hooch agreed. "I suggest we stop it."

"The freezer control isn't functioning," Willows said. "I guess that's
what they went in there to correct."

"I doubt it," de Hooch said carefully. "They wouldn't have needed suits
for that. They must have had something else bothering them. I'd be
willing to bet they went in to pull a sample and something went wrong."

"Why? What makes you think so?"

"If there'd been trouble, they'd have called for someone to stay here
at the console. Both of them wouldn't have gone in if there was any
trouble."

"Yeah. Yeah, I guess you're right." He looked visibly relieved. "What do
you suppose went wrong?"

"Look at your meters. Four of 'em aren't registering."

Willows looked. "I hadn't noticed. I thought they were just registering
low. You're right, though. Yeah. You're right. The surface bleed-off.
Hydrogen loss. Blew a valve, is all. Yeah." He grinned a little.
"Must've been quite a volcano for a second or two."

De Hooch grinned back at him. "Yeah. Must've. Give me a hand with these
clamps."

Willows began fastening the clamps on the heavy suit. "D'you think
Ferguson and Metty are O.K., Guz?" he asked.

De Hooch noticed it was the first time he had used the names of the two
men. Now that there was a chance that they were alive, at least in his
own mind, he was willing to admit that they were men he knew. Willows
didn't want to think that anyone he knew had done such a terrible thing
as die. It hit too close to home.

The man wasn't thinking. He was willing to grasp at anything that
offered him a chance--dream straws. The idea was to keep him busy, keep
his mind on trivia, keep him from thinking about what was going on
inside that reactor.

He should have known automatically that it was building toward Fermium
256. It was the most logical, easiest, and simplest way for a D-H
reactor to go off the deep end.

A Ditmars-Horst reactor took advantage of the fact that any number can
be expressed as the sum of powers of two--and the number of nucleons in
an atomic nucleus was no exception to that mathematical rule.

Building atoms by adding nucleons wasn't as simple as putting marbles in
a bag because of the energy differential, but the energy derived from
the fusion of the elements lighter than Iron 56 could be compensated for
by using it to pack the nuclei heavier than that. The trick was to find
a chain of reactions that gave the least necessary energy transfer. The
method by which the reactions were carried out might have driven a
mid-Twentieth Century physicist a trifle ga-ga, but most of the
reactions themselves would have been recognizable.

There were several possible reactions which Ferguson and Metty could
have used to produce Hg-203, but de Hooch was fairly sure he knew which
one it was. The five-branch, double-alpha-addition scheme was the one
that was easiest to use--and it was the only one that started the
damnable doubling chain reaction, where the nuclear weights went up
exponentially under the influence of the peculiar conditions within the
reactor. 2-4-8-16-32-64-128-256 ... Hydrogen 2 and Helium 4 were stable.
So were Oxygen 16 and Sulfur 32. The reaction encountered a sticky spot
at Beryllium 8, which is highly unstable, with a half life of ten to
the minus sixteenth seconds, spontaneously fissioning back into two
Helium 4 nuclei. Past Sulfur 32, there was a lot of positron emission as
the nuclei fought to increase the number of neutrons to maintain a
stable balance. Germanium 64 is not at all stable, and neither is
Neodymium 128, but the instability can be corrected by positive beta
emission. When two nuclei of the resulting Xenon 128 are forced
together, the positron emission begins long before the coalescence is
complete, resulting in Fermium 256.

But not even a Ditmars-Horst reactor can stand the next step, because
matter itself won't stand it--not even in a D-H reactor. The trouble is
that a D-H reactor _tries_. Mathematically, it was assumed that the
resulting nucleus did exist--for an infinitesimal instant of time.
Literally, mathematically, infinitesimal--so close to zero that it would
be utterly impossible to measure it. Someone had dubbed the hypothetical
stuff Instantanium 512.

Whether Instantanium 512 had any real existence is an argument for
philosophers only. The results, in any case, were catastrophic. The
whole conglomeration came apart in a grand splatter of neutrons,
protons, negatrons, positrons, electrons, neutrinos--a whole slew of
Greek-lettered mesons of various charges and masses, and a fine
collection of strange and ultrastrange particles. Energy? Just oodles
and gobs.

Peter de Hooch had heard about the results. He had no desire to
experience them first hand. Fortunately, the reaction that led up to
them took time. It could be stopped at any time up to the Fm-256 stage.
According to the instruments, that wouldn't be for another six hours
yet, so there was nothing at all to worry about. Even after that it
could be stopped, provided one had a way to get rid of the violently
fissioning fermium.

"Connections O.K.?" Willows asked. His voice came over the earphones
inside the ponderous helmet of the radiation suit.

"Fine," said de Hooch. He adjusted the double periscope so that his
vision was clear. "Perfect."

He tested the controls, moving his arms and legs to see if the suit
responded. The suit was so heavy that, without powered joints,
controlled by servomechanisms, he would have been unable to move, even
under Lunar gravity. With the power on, though, it was no harder than
walking underwater in a diving suit. "All's well, Puss," he said.

"I'll keep an eye on you," said Willows.

"Fine. Well, here goes Colossus de Hooch." He began walking toward the
door that led into the corridor which connected the reactor anteroom to
the control room.

       *       *       *       *       *

It took time to drag the two inert figures out of the anteroom. All de
Hooch could do was grab them under the armpits, apply power, and drag
them out. He went out the same way he had come in, traversing the
separate chambers in reverse order. First came the decontamination
chamber, where the radioactive dust that might have settled on the suits
was sluiced off by the detergent sprays. When the radiation detectors
registered low enough, de Hooch dragged Ferguson into the outer chamber,
then went back and got Metty and put him through the same process. Then
he dragged them on into the control room so that Willows could get them
out of the heavy suits.

[Illustration]

"Can you help me, Guz?" Willows asked. It was obvious that he didn't
want to open the suits. He didn't want to see what might be inside. De
Hooch helped him.

They were both alive, but unconscious. Bones had been broken, and Metty
appeared to be suffering from concussion. They were badly damaged, but
they'd live.

De Hooch and Willows made two trips down E and C corridors, carrying the
men on a stretcher, to get them in bed. De Hooch splinted the broken
bones as best he could and gave each of them a shot of narcodyne. He had
to do the medical work because Quillan, the medic, was trapped in
Corridor A. He called Quillan on the phone to tell him what had
happened. He described the signs and symptoms of the victims as best he
could, and then did what Quillan told him to do.

"They ought to be all right," Quillan said. "With that dope in them,
they'll be out cold for the next twelve hours, and by that time, the
boys from Base will be here. Just leave 'em alone and don't move 'em any
more."

"Right. I'll call you back later. Right now, Puss and I are going to see
what's wrong with the control linkages on Number Two."

"Right. By-o."

De Hooch and Willows walked back to the control room of Number Two
Reactor in silence.

Once inside the control room, de Hooch said: "How are those control
circuits?" Willows was supposed to have been checking them while he had
been dragging Ferguson and Metty out of the antechamber.

"Well, I ... I'm not sure. I'll show you what I've found so far, Guz.
You ought to take a look at them. I ... I'd like you to take a look-see.
I think"--he gestured toward the console--"I think they're all right
except for the freezer vernier and the pressure release control."

_He doesn't trust his own work_, de Hooch thought. _Well, that's all
right. Neither do I._

Painstakingly, the two of them went over the checking circuits. Willows
was right. The freezer and pressure controls were inoperable.

"Damn," said de Hooch. "Double damn."

"They're probably both stuck at the firewall," Willows said.

"Sure. Where else? I'll have to go in there and unstick 'em. Help me get
back into that two-legged tank again." He wished he knew more about what
Ferguson and Metty had been doing. He wished he knew why the two men had
gone into the anteroom in the first place. He wished a lot of things,
but wishing was a useless pastime at this stage of the game.

If only one of the two men had been in a condition to talk!

He got back into his radiation-proof suit again, took one last look at
the instruments on the console, and headed for the reactor.

       *       *       *

Through the first radiation trap--left turn, right turn, right turn,
left turn--through the "cold" room, through the second radiation trap,
through the decontamination chamber, and through the third radiation
trap into the anteroom. Now that Ferguson and Metty were safely out of
the way, he could give his attention to the damage that had been done.

Had Ferguson and Metty actually come in to tap off a sample, as he had
suggested to Willows? He looked around at the wreckage in the
antechamber. Quite obviously, the heavy door of the sample chamber was
wide open, and it certainly appeared that the wreckage was scattered
from that point. Cautiously, he went over to look at the open sample
chamber. It looked all right, except that the bottom was covered with a
bright, metallic dust. He rubbed his finger over it and looked at the
fingertip. A very fine dust. And yet it hadn't been scattered very much
by the explosion. Heavy. Very likely osmium. Osmium 187 was stable, but
it wasn't a normally used step toward Mercury 203. Four successive alpha
captures would give Polonium 203, not mercury. Ditto for an oxygen
fusion. It could be iridium or platinum, of course. Whatever it was, the
instruments in his helmet told him it wasn't hot.

He had a hunch that Ferguson and Metty had been building Mercury 203
from Hafnium 179 by the process of successive fusions with Hydrogen 3
and that something had gone wrong with the H-3 production. It appeared
that the explosion had been a simple chemical blast caused by the air
oxidation of H-2. But the bleeder vent at the other end of the reactor
had apparently kicked at the same time. An enormous amount of unused
energy had been released, blowing the entire emergency bleeder system
out.

Something didn't seem right. Something stuck in his craw, and he
couldn't figure out what it was.

He opened up the conduit boxes that led through the antechamber from the
control console to the reactor beyond the firewall. Everything looked
fine. That meant that whatever it was that had fouled up the controls
was on the other side of the firewall.

"How does it look?" Willows' voice came worriedly over the earphones.

"Have I already said 'damn'?" de Hooch asked.

"You have," Willows said with forced lightness. "You even said 'double
damn'."

"_Factorial_ damn, then!" said de Hooch.

"What's the matter?"

"Apparently the foul-up is on the _other_ side of the firewall."

"Are you going in?"

"I'll have to."

"All right. Watch yourself."

"I will." He went over to the periscope that surveyed the part of the
reactor beyond the firewall. Everything looked normal enough. He
carefully checked the pressure gauge. Normal.

"Check the spectro for me, will you?" he asked. "Make sure that's just
the normal helium atmosphere in there."

"Sure." A pause. "Nothing but helium, Guz. What were you expecting?"

"I don't think I'd care to walk into a hydrogen atmosphere at three
hundred Centigrade."

"Neither would I, but how could there be hydrogen in there?"

"There shouldn't be. But there's something screwy going on here, and I
can't put my finger on it."

"Well, whatever it is, it isn't hydrogen in the reactor room."

"O.K. Stand by. I'm going in."

He walked over to the firewall door. On the other side of it was a small
chamber where the oxygen and nitrogen of normal air would be swept out
before he opened the inner door to go into the inner chamber itself.
There was no need for an air lock, since small amounts of impurities in
the He-4 didn't bother anything.

It was just as he turned the lever that undogged the firewall door that
he realized his mistake.

But it was too late.

The door jerked outward, and a hot wind picked him up and slammed him
against the far wall.

There was a moment of pain.

Then--nothing.

       *       *       *       *       *

_There was something familiar about the man who was turning the wheel,
but de Hooch couldn't place it. The man was wearing a black hood, as
befitted a torturer and executioner._

_"Idiot," said the hooded man, giving the wheel of the rack a little
more pressure, "explain the following: If a half plus a half is equal to
a whole, why is halfnium plus halfnium not equal to wholmium?"_

_Stretched as he was on the rack, de Hooch could not think straight
because of the excruciating pain._

_"Because a half is eight point two eight per cent heavier than a hole,"
said de Hooch._

_"You are an idiot, none the less," said the torturer. He gave the wheel
another twist. De Hooch wanted to scream, but he couldn't._

_"Try again," said the torturer. "What is a half plus four plus four
plus four plus four plus--"_

"Stop!" _screamed de Hooch_. "Stop! _Stop at the osmium!_"

_"Ah! But it_ didn't _stop at the osmium," said the hooded man. "It went
on and on and on. Plus four plus four plus four plus four plus
four--until there were so many plus fours in there that the place looked
like an old-fashioned golf course."_

_"My legs hurt," said de Hooch. The man was no longer wearing a hood,
but de Hooch couldn't tell if it was Willows or himself._

_"We will all go together when we go," said the man._

_De Hooch turned his head away and looked at the ceiling._

And he realized that it was the ceiling of the antechamber.

"My legs hurt," he repeated. And he could hear the hoarse whisper inside
the helmet. He realized that he was lying flat on his back. He had been
jarred around quite a bit in the suit.

He wondered if he could sit up. He managed to get both arms behind him
and push himself into a sitting position. He wiggled his feet. The
servos responded. He hurt all over, but a little experiment told him
that he was only bruised. Nothing was broken. He hadn't been hit as hard
as Ferguson and Metty had been.

"Willows?" he said. "Willows?"

There was no answer from the earphones.

He looked at the chronometer dial inside his helmet. Oh two forty-nine.
He had been unconscious less than ten minutes.

The same glance brought his eyes to two other dials. The internal
radiation of the suit was a little high, but nothing to worry about. But
the dial registering the external radiation was plenty high. Without the
protection of the suit, he wouldn't have lived through those ten
minutes.

Where was Willows?

And then he knew, and he pushed any thought of further help from that
quarter out of his mind. What had to be done would have to be done by
Peter de Hooch alone. He climbed to his feet.

His head hurt, and he swayed with nausea and pain. Only the massive
weight of the suit's shoes kept him upright. Then it passed, and he
blinked his eyes and shook his head to clear it. He found he was holding
his breath, and he let it out.

The trouble had been so simple, and yet he hadn't seen it. Oh, yes, he
had! He _must_ have, subconsciously. Otherwise, how would he have
guessed that the stuff in the sampling chamber was Osmium 187? Ferguson
and Metty _had_ been trying to make Mercury 203 by adding eight
successive tritium nuclei to Hafnium 179, progressing through Tantalum
182, Tungsten 185, Rhenium 188, Osmium 191, Iridium 194, Platinum 197,
and Gold 200, all of which were unstable.

But the Hydrogen 3 reaction had gone wrong. The doubling had set in,
producing Helium 4. Successive additions of the alpha particles to
Hafnium 179 had produced, first, Tungsten 183, and then Osmium 187, both
of which were stable.

Ferguson and Metty, seeing that something was wrong, drew off a sample
and then reset the reaction to produce the Hg-203 they wanted. Then they
had come down to pick up the sample.

They hadn't realized that the helium production had gone wild. Much more
helium than necessary was being produced, and the bleeder valve had
failed. When they opened the sample chamber, they got a blast of
high-pressure helium right in the face. The shock of that sudden release
had jarred the whole atmosphere inside the reaction chamber, and the
bleeder valve had let go. But the violence of the pressure release had
caused a fault to the surface to open up and had closed the valve
again--jammed it, probably. There had been enough pressure left in there
to blow de Hooch up against the nearest wall when he opened the door.
Since the pressure indicator system was connected to the release system,
when one had failed, the other had failed. That's why the pressure gauge
had indicated normal.

And, of course, it had been the pressure differential that had caused
the controls to stick. Well, they ought to be all right now, then. He
decided he'd better take a look.

       *       *       *

The firewall door was still open. He walked over to it and stepped into
the small chamber that led to the inner reactor room. The inside door,
much weaker than the outer firewall door, had been blown off its hinges.
He stepped past it and went on in.

What he saw made him jerk his glance away from the periscope in his
helmet and check his radiation detectors again. Not much change. Relief
swept over him as he looked back at the reactor itself. The normally
dead black walls were glowing a dull red. It was pure thermal heat, but
it shouldn't be doing that.

Moving quickly, he went over to the place where the control cables came
in through the firewall. It took him several minutes to assure himself
that they would function from the control room now. There was nothing
more to do but get out of here and get that reaction damped.

He went out again, closing the firewall door behind him and dogging it
tight. There would be no more helium production now.

He went through the radiation trap to the decontamination chamber to
wash off whatever it was he had picked up.

The decontamination room was a mess.

De Hooch stared at the twisted pipes and the stream of water that gushed
out of a cracked valve. The blast had jarred everything loose. Well, he
could still scrub himself off.

Except that the scrubbers weren't working.

He swore under his breath and twisted the valve that was supposed to
dispense detergent. It did, thank Heaven. He doused himself good with it
and then got under the flowing water.

The radiation level remained exactly where it was.

He walked over and pulled one of the brushes off the defunct scrubber
and sudsed it up. It wasn't until he started to use it that he got a
good look at his arms. He hadn't paid any attention before.

He walked over to the mirror to get a good look.

"You look magnificent," he told his reflection acidly.

The radiation-proof armor looked as though it had been chrome plated.

But de Hooch knew better than that. He knew exactly what had happened.
He was nicely plated all over with a film of mercury, which had
amalgamated itself with the metallic surface of the suit. He was
thoroughly wet with the stuff and no amount of water and detergent would
take it off.

There was something wrong with Number Two Reactor, all right. It had
leaked out some of the Mercury 203 that Ferguson and Metty had been
making.

He thought a minute. It hadn't been leaking out just before he opened
the door in the firewall, because Willows would certainly have noticed
the bright mercury line when he checked with the spectroscope. The stuff
must have been released when the pressure dropped.

He walked back to the anteroom and looked at the sampling chamber. There
were a few droplets of mercury around the inlet.

Thus far, the three pressure explosions had wrecked about everything
that was wreckable, he thought. No, not quite. There was still the
chance that the whole station would go if he didn't get back into the
control room and stop that "powers of two" chain. The detonation of
Instantanium 512 would finish the job by doing what high-pressure helium
could never do.

He glanced at the thermometer. The temperature behind the firewall had
risen to two-forty Centigrade. It wasn't supposed to be above two
hundred. It wasn't too serious, really, because a little heat like that
wouldn't bother a Ditmars-Horst reactor, but it indicated that things
back there weren't working properly.

He turned away and walked back to the decontamination chamber. There
must be some way he could get the mercury off the suit--because he
couldn't take the suit off until the mercury was gone.

       *       *       *       *       *

First, he tried scrubbing. That was what showed him how upset he really
was. He had actually scrubbed the armor on his left arm free of mercury
when he realized what he was doing and threw the brush down in disgust.

"Use your head, de Hooch!" he told himself. What good would it do to
scrub the stuff off of the few places he could reach? In the bulky
armor, he was worse than muscle-bound. He couldn't touch any part of his
back; he couldn't bend far enough to touch his legs. His shoulders were
inaccessible, even. Scrubbing was worse than useless--it was
time-wasting.

He picked up the brush again and began scrubbing at the other arm. It
gave him something to do while he thought. While he was thinking, he
wasn't wasting time.

What would dissolve mercury? Nitric acid. Good old HNO{3}. Fine. Except
that the hot lab was at the other end of the reactor, where the fissure
had let all the air out. The bulkheads had dropped, and he couldn't get
in. And, naturally, the nitric acid would be in the lab.

For the first time, he found himself hating Willows' guts. If he were
around, he could get some acid from the cold lab, or even from the other
hot lab at Number One. If Willows--

He stood up and dropped the brush. "Dolt! Boob! Moron! Idiot!" Not
Willows. Himself. There was no reason on earth--or Luna--why he couldn't
walk over to Number One hot lab and get the stuff himself. The habit of
never leaving the lab without thorough decontamination was so thoroughly
ingrained in him that he had simply never thought about it until that
moment. But what did a little contamination with radioactive mercury
mean at a time like this? He could take F corridor to Number One, use
the decontamination chamber and the acid from the lab, shuck off his
armor there, and come back through E corridor. F could be cleaned up
later.

So simple.

He went through the light trap to the next chamber and turned the handle
on the sliding door. The door wouldn't budge. It had been warped by the
force of the helium blast, and it was stuck in its grooves.

Well, there were tools. The thing could be unstuck.

Peter de Hooch was a determined man, a strong man, and a smart man. But
the door was more determined and stronger than he was, and his
intelligence didn't give him much of an edge right then. After an hour's
hard work, he managed to get the door open about eighteen inches. Then
it froze fast and refused to move again. All the power and leverage he
could bring to bear was useless. The door had opened all it was going to
open. Beyond it, he could see the next radiation trap--and freedom.

Eighteen inches would have been plenty of space for him to get through
if he had not been wearing the radiation-proof suit. But he didn't dare
take that suit off. By the time he got out of the suit, the intensely
radioactive mercury on its surface would have made his death only a
matter of time. And not much time at that.

He told himself that if it were simply a matter of running to the
control room to shut off the D-H reactor, he'd do it. That could have
been done before he lost consciousness. But it wasn't that easy. Damping
the reaction took time and control. The stuff had to be eased back
slowly. Shutting off the Ditmars-Horst would simply blow a hole in the
crust of Luna and kill everyone if he did it now. There were four or
five men out there who would die if he pulled anything foolish like
that. The explosion wouldn't be as powerful as the Instantanium 512
reaction would be, but it would be none the less deadly for all that.

There had to be either a way to scrape the mercury off the suit or a way
to open the door another six inches.

Or, he added suddenly, a way to get safely out of the suit.

       *       *       *

At the end of another twenty minutes, he had still thought of nothing.
He wandered around the decontamination room, looking at everything,
hoping he might see something that would give him a clue. He didn't.

He went into the antechamber of the reactor and glared at the door in
the firewall. The instruments said that things were getting pretty
fierce on the other side of that wall. Temperature: Two ninety-five and
still rising. Pressure? He carefully cracked the inlet of the sampling
chamber and got a soft hiss. The helium was expanding from the heat,
that was all. Part of the trouble with the reactor, he thought, was the
high percentage of oxygen and nitrogen that had mixed in during the ten
minutes or so that the door was open. All hell was fixing to bust loose
in there, and he, Peter de Hooch, was right next to it.

He walked back into the decontamination chamber.

What would dissolve mercury?

Mercury would dissolve gold. Would gold dissolve mercury?

Very funny.

He was like a turtle, de Hooch thought. Perfectly safe as long as he was
in his shell, but take him out of it and he would die.

_Hell of a way to spend the night_, he thought. _A night in shining
armor._

That struck him as funny. He began to laugh. And laugh.

He almost laughed himself sick before he realized that it was fear and
despair that were driving him into hysteria, not a sense of humor. He
forced himself to calmness.

He must be calm.

He must think.

Yes.

How do you go about getting rid of a radioactive metal that is in effect
welded to the outside of your suit?

The trouble was, he was a nucleonics engineer, not a chemist. He
remembered quite a bit of his chemistry, of course, but not as much as
he would have liked.

Could the stuff be neutralized?

Sure, he told himself. Very simple. All he had to do was go climb into
the reactor, and let the reactor do the job. Mercury 203 plus an alpha
particle gives nice, stable Lead 207. Just go climb right into the
Ditmars-Horst and let the Helium 4 do the job.

But the thought stuck in his mind.

He kept telling himself not to panic as Willows had done.

And several minutes later, chuckling to himself in a half demented
fashion, he opened the firewall door and went in to let the helium do
the job.

       *       *       *

It was nearly eight in the morning, Greenwich time, when the three
surface vehicles, with their wide Caterpillar treads lumbered to a halt
near the kiosk that marked the entrance to the underground site of the
laboratories.

"O.K.," said one of the men in the first machine, holding a microphone
to his lips, "let's go in. If what Willows said is true, the whole place
may blow any minute now, but I'm not asking for volunteers. Nobody will
be any safer up here than they will down there, and we have to do a job.
Besides, Willows wasn't completely rational. Nobody would put on a vac
suit and run away like that if he was in his right mind. So we can
discount a lot of what he said when we picked him up on the road.

"The five of us in this car are going straight to Number One Reactor to
see what can be done to stop whatever is going on. The rest of you start
trying to see if you can get those trapped men out of A and B corridors.
All right, let's move in."

Less than five minutes later, five men went into the control room of
Number One Reactor. They found Peter de Hooch sound asleep in the
control chair, and the instruments showed that the Ditmars-Horst reactor
was inactive.

One of the men shook de Hooch gently, awakening him in the middle of a
snore.

"What?" he said groggily.

"We're here, Guz. Everything's O.K."

"Sure everything's O.K. Nothing to it. All I did was wait until the
temperature got above three fifty-seven Centigrade--above the boiling
point of mercury. Then I went in and let the hot helium _boil_ the stuff
off me. Nothing to it. Near boiled myself alive, but it did the trick."

"What," asked the man in a puzzled voice, "are you talking about?"

"I am a knight in dull armor," said Peter de Hooch, dozing off again.

Then he roused himself a little, and said, without opening his eyes: "Hi
yo, Quicksilver, away." And he was sound asleep again.


    _And when he saw what he had done,
    With all his might and main,
    He jumped back in that bramble bush
    And scratch'd them in again!..._







End of Project Gutenberg's The Bramble Bush, by Gordon Randall Garrett