Hanging by a Thread Page 4

man--the velocity of our ship will be indicated by theDoppler Effect. That is, our motion toward or away from them can becalculated that way. Our angular velocity with respect to them can bechecked while the screamer is going; they will know which directionwe're moving, if we're moving at an angle.

  "With that information, all they have to do is find out which ship isin that general area of the sky, which they can find out by checkingthe schedule, and they can estimate approximately where we'll be. TheIP ship will come out, and when they get in the general vicinity, theycan find us with their meteor detectors. Nothing to it."

  "And," Captain Al-Amin added, "since we have eight screamers stillleft with us, we have plenty of reserves to call upon. There'snothing to worry about, Mr. Hull."

  "But how can you aim a beam when we're toppling end-over-end likethis?" Hull asked.

  "Well, if we couldn't stop the rotation," said the captain, "we'dbroadcast instead of beaming. Anywhere within the Solar System, ascreamer can broadcast enough energy to overcome the background noise.

  "The IP would have a harder time finding us, of course, but we'd besaved eventually."

  "I see," said Hull "How do we go about stopping the rotation?"

  "That's the next thing on the agenda," Al-Amin said. "This seasickroll is caused by the unevenness of the load, and I'm pretty sick ofit, myself. Smith, will you and Mr. Kelvin get out the emergencyrockets? We'll see what we can do to stabilize our platform."

  * * * * *

  It took better than an hour to get the ship straightened out. For themain job, emergency rockets were set off at the appropriate spotsaround the hull to counteract the rotation. The final trimming wasdone with carbon dioxide fire extinguishers, which Smith and JayjayKelvin used as jets.

  Getting a fix on Pluto was easy enough; the lighthouse station at Styxbroadcast a strong beep sunward every ten seconds. They could alsopick up the radio lighthouses on Eros, Ceres, Luna, and Mimas.Evidently, the one on Titan was behind the Jovian bulk.

  They were ready to send their distress call.

  "It's simple," Smith said as he opened the red panel in the wall ofthe control room. "First we turn on the receiver." He pushed a buttonmarked _R_. "Then we turn these two wheels here until the pip on thatlittle screen is centered. That's the signal from Pluto. It comes instrong every ten seconds, see?"

  Jayjay watched with interest. He'd heard about screamers and had seenthem, but he'd never had the opportunity of observing one in action.

  Like flares or bombs, they were intended for one-time use. Theinstructions were printed plainly on the inside of the red door, andSmith was simply reading off what was printed there.

  "These wheels," he was saying, "line up the parabolic reflector withthe Pluto signal, you see. There. Now we've got it centered. Now, allwe have to do is make one small correction and we're all set. Thesethings are built so that they're fool-proof; a kid could operate it.Watch."

  Facing each other across a small gap were a pair of tapered screwplugs, one male and one female. The male was an average of half aninch in diameter; the female was larger and bored to fit the male.

  "The female plug," Smith said, "leads to two tanks of high-pressuregas inside this cabinet on the left. One tank of oxygen, one ofhydrogen. See how this male plug telescopes out to fit into thefemale? All we have to do is thread them together, and everything isautomatic."

  Jayjay was aware that Smith's explanations were meant to give JeffryHull something to think about instead of his fears. Hull was basicallyan Earth-hugger, and free fall did nothing to keep him calm. Evidentlyhis subconscious knew that he had to latch on to something to keep hismental equilibrium, because he showed a tremendous amount of interestin what should have been a routine operation.

  "How do you mean, it's all automatic?" he asked. "What happens?"

  "Well, you can't see into the female plug, but look here at the male.See those concentric tubes leading into the interior of the cabinet onthe right? The outer one leads in the oxygen, the inner leads in thehydrogen. We need twice as much hydrogen as oxygen, so the inner tubehas twice the volume delivery as the outer. See?"

  "Yes. But what is the solid silver bar in the center of the innertube?"

  "That's the electrical connection for the starter battery. There's asmall, short-lived chemical battery, like the ones in an ordinarypocket radio, except that they're built to deliver a high-voltage,high-amperage current for about a tenth of a second. That activatesthe H-O cell, you see. Also, that silver stud depresses thecorresponding stud in the female plug, which turns on the gas flowbefore it makes the connection with the starter battery. Follow?"

  Hull didn't look as though he did, but he nodded gamely. "Then whathappens?"

  "Then the hydrogen and the oxygen come together in the fuel cell and,instead of generating heat, they generate electric current. Thatcurrent is fed into the radio unit, and the signal is sent to Pluto.Real simple."

  "I see," Hull said. "Well ... go ahead."

  Smith telescoped the two leads together and began turning the collaron the female plug.

  He screwed it up as far as it would go.

  And nothing happened.

  "What the hell?" asked Smith of no one in particular. He tried totwist it a little harder. Nothing happened. The threads had gone asfar as they would go.

  "What's the matter?" Jayjay asked.

  "Damfino. No connection. Nothing's happening. And it's as tight as itwill go."

  "Are the gases flowing?" Jayjay asked.

  "I don't know. These things aren't equipped with meters. They'resupposed to work automatically."

  Jayjay pushed Smith aside. "Let me take a look."

  Smith frowned as though he resented an ordinary passenger shoving himaround, but Jayjay ignored him. He cocked his head to one side andlooked at the connection. "Hm-m-m." He touched it with a finger. Thenhe wet the finger with his tongue and touched the connection again."There's no gas flow, Smith."

  "How do you know?" Smith was still frowning.

  "There's a gap there. That tapered thread isn't in tight. If therewere any gas flowing, it would be leaking out." Before Smith could sayanything Jayjay began unscrewing the coupling. When it came apart, itlooked just the same as it had before Smith had put it together.

  In the dim glow from the emergency lights, it was difficult to seeanything.

  "Got an electric torch?" Jayjay asked.

  Smith pushed himself away from the screamer panel and came back aftera moment with a flashlight. "Let me take a look," he said, edgingJayjay aside. He looked over the halves of the coupling verycarefully, then said: "I don't see anything wrong. I'll try it again."

  "Hold on a second," Jayjay said quietly. "Let me take a look, willyou?"

  Smith handed him the torch. "Go ahead, but there's nothing wrong."

  * * * * *

  Jayjay took the light and looked the connections over again. Then hescrewed his head around so that he could look into the female plug.

  "Hm-m-m. Hard to count. Gap's too small. Anybody got a toothpick?"

  Nobody did.

  Jayjay turned to Jeffry Hull. "Mr. Hull, would you mind going to thelounge? I think there's some toothpicks in the snack refrigerator."

  "Sure," said Hull. "Sure."

  He pushed himself across the control room and disappeared through thestairwell.

  "Get several of them," Jayjay called after him.

  Captain Al-Amin said: "What's the trouble, Mr. Kelvin?"

  "I'm not sure yet," Jayjay answered. "When did you last have thescreamer units inspected?"

  "Just before we took off from Jove Station," Al-Amin said. "That's thelaw. All emergency equipment has to be checked before takeoff. Why?What's the matter?"

  "Did they check this unit?" Jayjay asked doggedly.

  "Certainly. I watched them check it myself. I--" He brought himself upshort and said: "Give me that torch, will you? I want to take a lookat the thing."

  Ja
yjay handed him the flashlight and grasped the captain's belt. Withone arm in a splint, Al-Amin couldn't hold the flashlight and hold onto anything solid at the same time.

  "I don't see anything wrong," he said after a minute.

  "Neither do I," Jayjay admitted. "But the way it acts--"

  "I got the toothpicks!" Jeffry Hull propelled himself across the roomtoward the three men who were clustered around the screamer.

  Jayjay took the toothpicks, selected one, and