emed 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