"Then the hydrogen and the oxygen come together in the fuel cell and, instead of generating heat, they generate electric current. That current 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 collar on 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 to twist it a little harder. Nothing happened. The threads had gone as far as they would go. "What's the matter?" Jayjay asked. "Damfino. No connection. Nothing's happening. And it's as tight as it will go." "Are the gases flowing?" Jayjay asked. "I don't know. These things aren't equipped with meters. They're supposed to work automatically." Jayjay pushed Smith aside. "Let me take a look." Smith frowned as though he resented an ordinary passenger shoving him around, but Jayjay ignored him. He cocked his head to one side and looked at the connection. "Hm-m-m." He touched it with a finger. Then he 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 there were any gas flowing, it would be leaking out." Before Smith could say anything Jayjay began unscrewing the coupling. When it came apart, it looked just the same as it had before Smith had put it together. In the dim glow from the emergency lights, it was difficult to see anything. "Got an electric torch?" Jayjay asked. Smith pushed himself away from the screamer panel and came back after a moment with a flashlight. "Let me take a look," he said, edging Jayjay aside. He looked over the halves of the coupling very carefully, 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, will you?" Smith handed him the torch. "Go ahead, but there's nothing wrong." * * * * * Jayjay took the light and looked the connections over again. Then he screwed 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 the lounge? I think there's some toothpicks in the snack refrigerator." "Sure," said Hull. "Sure." He pushed himself across the control room and disappeared through the stairwell. "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 the screamer units inspected?" "Just before we took off from Jove Station," Al-Amin said. "That's the law. All emergency equipment has to be checked before takeoff. Why? What's the matter?" "Did they check this unit?" Jayjay asked doggedly.