dous overdose of sleeping pills. On the table was his daily-report
log and his last entry, made three months before:

_I haven't attended to the instruments for a long time because it hates
us and doesn't want us here. It hates me the most of all and keeps
trying to get into the bubble to kill me. I can hear it whenever I stop
and listen and I know it won't be long. I'm afraid of it and I want to
be asleep when it comes. But I'll have to make it soon because I have
only twenty sleeping pills left and if--_

The sentence was never finished. According to the temperature recording
instruments in the bubble his body ceased radiating heat that same
night.

* * * * *

The bubble was cleaned, fumigated, and inspected inside and out. No sign
of any inimical entity or force could be found.

Silverman was Horne's replacement. When the cruiser returned six months
later bringing him, Green, to be Silverman's replacement, Silverman was
completely insane. He babbled about something that had been waiting
outside the bubble to kill him but his nearest to a rational statement
was to say once, when asked for the hundredth time what he had seen:

"Nothing--you can't really see it. But you feel it watching you and you
hear it trying to get in to kill you. One time I bumped the wall
and--for God's sake--take me away from it--take me back to Earth ..."

Then he had tried to hide under the captain's desk and the ship's doctor
had led him away.

The bubble was minutely examined again and the cruiser employed every
detector device it possessed to search surrounding space for light-years
in all directions. Nothing was found.

When it was time for the new replacement to be transferred to the bubble
he reported to Captain McDowell.

"Everything is ready, Green," McDowell said. "You are the next one." His
shaggy gray eyebrows met in a scowl. "It would be better if they would
let me select the replacement instead of them."

He flushed with a touch of resentment and said, "The Bureau found my
intelligence and initiative of thought satisfactory."

"I know--the characteristics you don't need. What they ought to have is
somebody like one of my engine room roustabouts, too ignorant to get
scared and too dumb to go nuts. Then we could get a sane report six
months from now instead of the ravings of a maniac."

"I suggest," he said stiffly, "that you reserve judgement until that
time comes, sir."

*