nd
the molten covering metal poured into it. It must have a much lower
melting point than the steel of the engine so there would be no
damage. They just have a better knowledge of metal technology in the
city and counted on your ignorance."

"Ignorance! You insult--"

"I take it back. I just meant they thought they could get away with
the trick, and since they didn't they are the stupid ones. Does that
satisfy you?"

"What do you do next?"

"I take off the nuts and when I do there is a good chance that the
poison-hood will be released and can simply be lifted off."

"It is too dangerous for you to do, the fiends may still have other
traps ready when the nut is turned. I will send a strong slave to turn
them while we watch from a distance, his death will not matter."

"I'm touched by your concern for my health, but as much as I would
like to take advantage of the offer, I cannot. I've been over the same
ground and reached the reluctant conclusion that this is one job of
work that I have to do myself. Taking off those nuts looks entirely
too easy, and that's what makes me suspicious. I'm going to do it and
look out for any more trickery at the same time--and that is something
that only I can do. Now I suggest you withdraw with the troops to a
safer spot."

There was no hesitation about leaving, footsteps rustled quickly on
the sand and Jason was alone. The leather walls flapped slackly in the
wind and there was no other sound. Jason spat on his palms, controlled
a slight shiver and slid into the pit. The wrench fitted neatly over
the nut, he wrapped both hands around it and, bracing his leg against
the pit wall, began to pull.

And stopped. Three turns of thread on the bolt projected below the
nut, scraped clean of metal by the industrious Mikah. Something about
them looked very wrong but he didn't know quite what.

[Illustration]

"Mikah," he shouted, and had to call loudly two more times before his
assistant poked his head tentatively around the screen. "Nip over to
the petroleum works and get me one of their bolts threaded with a nut,
any size, it doesn't matter."

Jason warmed his hands by the stove until Mikah returned with the oily
bolt, then waved him out to rejoin the others. Back in the pit he held
it up next to the protruding section of Appsalan bolt and chortled
with joy. The threads on the angle bolt were canted at a slightly
different angle: where one ran up, the other ran down. The Appsalan
t