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 whate