***
Edipon must have been keeping track of the work progress because he was waiting near the engine when Jason returned with the completed wrench.
“I have been under,” he announced, “and have seen the nuts that the devilish Appsalanoj have concealed within solid metal. Who would have suspected! It still seems to me impossible that one metal could be hidden within another, how could that be done?”
“Easy enough. The base of the assembled engine was put into a form and 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.
“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 threads had been cut in reverse, with a lefthand thread.
Throughout the galaxy there existed as many technical and cultural differences as there were planets, yet one of the few things they all had in common, inherited from their terrestrial ancestors, was a uniformity of thread. Jason had never thought about it before, but when he mentally ran through his experiences on different planets he realized that they were all the same. Screws went into wood, bolts went into threaded holes and nuts all went onto bolts when you turned them with a clockwise motion. Counterclockwise removed them. In his hand was the crude D’zertano nut and bolt, and when he tried it it moved in the same manner. But the engine bolt did not work that way — it had to be turned clockwise to remove it.
***
Dropping the nut and bolt he placed the wrench on the massive engine bolt and slowly applied pressure in what felt like the completely wrong direction, as if he were tightening not loosening. It gave slowly, first a quarter then a half turn. And bit by bit the projection threads vanished until they were level with the surface of the nut. It turned easily now and within a minute it fell into the pit — he threw the wrench after it and scrambled out. Standing at the edge he carefully sniffed the air, ready to run at the slightest smell of gas. There was nothing.
The second nut came off as easily as the first and with no ill effects. Jason pushed a sharp chisel between the upper case and the baseplate where he had removed the solder, and when he leaned on it the case shifted slightly, held down only by its own weight.
From the entrance to the enclosure he shouted to the group huddled in the distance. “Come on back — this job is almost finished.”
They all took turns at sliding into the pit and looking at the projecting bolts and made appreciative sounds when Jason leaned on the chisel and showed how the case was free.
“There is still the little matter of taking it off,” he told them, “and I’m sure that grabbing and heaving is the wrong way. That was my first idea too, but the people who assembled that thing had some bad trouble in store for anyone who tightened those nuts instead of loosening them. Until we find out what that is we are going to tread very lightly. Do you have any big blocks of ice around here, Edipon? It is winter now, isn’t it?”
“Ice? Winter?” Edipon mumbled, caught off guard by the change of direction, rubbing abstractedly at the reddened tip of his prominent nose. “Of course it is winter. Ice, there must be ice at the higher lakes in the mountain, they are always frozen at this time of the year. But what do you want ice for?”
“You get it and I’ll show you. Have it cut in nice flat blocks that I can stack. I’m not going to lift the hood — I’m going to drop the engine out from underneath it!”
By the time the slaves had brought the ice down from the distant lakes Jason had rigged a strong wooden frame flat on the ground around the engine and pushed sharpened metal wedges under the hood, then had secured the wedges to the frame. Now, if the engine was lowered into the pit, the hood would stay above supported by the wedges. The ice would take care of this. Jason built a foundation of ice under the engine then slipped out the supporting bars. Now as the ice slowly melted the engine would be gently lowered into the pit.
The weather remained cold and the ice refused to melt until Jason had the pit ringed with smoking oil stoves. Water began to run down into the pit and Mikah went to work bailing it out, while the gap between the hood and the baseplate widened. The melting continued for the rest of the day and almost all of the night. Red-eyed and exhausted Jason and Mikah supervised the soggy sinking and when the D’zertanoj returned at dawn the engine rested safely in a pool of mud on the bottom of the pit: the hood was off.
“They’re tricky devils over there in Appsala, but Jason dinAlt wasn’t born yesterday,” he exulted. “Do you see that crock sitting there on top of the engine,” he pointed to a sealed container of thick glass the size of a small barrel, filled with an oily greenish liquid; it was clamped down tightly with padded supports. “That’s the booby trap. The nuts I took off were on the threaded ends of two bars that held the hood on, but instead of being fastened directly to the hood they were connected by a crossbar that rested on top of that jug. If either nut was tightened instead of being loosened, the bar would have bent and broken the glass. I’ll give you exactly one guess as to what would have happened then.”
“The poison liquid!”
“None other. And the double-walled hood is filled with it, too. I suggest that as soon as we have dug a deep hole in the desert the hood and container be buried and forgotten about. I doubt if the engine has many other surprises in store, but I’ll be careful as I work on it.”
“You can fix it? You know what is wrong with it?” Edipon was vibrating with joy.