DC."

"Then that's out. We run on 220 AC. And while I can rectify a few watts, it wouldn't be enough to help. No welders except monatomic hydrogen torches, even."

Pietro looked sicker than before. He'd obviously been counting on that. But he turned to Bullard. "How about seeds? We had a crop of tomatoes a month ago—and from the few I had, they're all seed. Are any left?"

Bullard rocked from side to side, moaning. "Dead. We're all gonna be dead. I told him, I did, you take me out there, I'll never get back. I'm a good man, I am. I wasn't never meant to die way out here. I—I—"

He gulped and suddenly screamed. He went through the door at an awkward shuffle, heading for his galley. Muller shook his head, and turned toward me. "Check up, will you, Mr. Tremaine? And I suggest that you and Mr. Peters start your investigation at once. I understand that chromazone would require so little hiding space that there's no use searching for it. But if you can find any evidence, report it at once."

Peters and I left. I found the galley empty. Apparently Bullard had gone to lie on his stomach in his bunk and nurse his terror. I found the freezer compartments, though—and the tomatoes. There must have been a bushel of them, but Bullard had followed his own peculiar tastes. From the food he served, he couldn't stand fresh vegetables; and he'd cooked the tomatoes down thoroughly and run them through the dehydrator before packing them away!

It was a cheerful supper, that one! Bullard had half-recovered and his fear was driving him to try to be nice to us. The selection was good, beyond the inevitable baked beans; but he wasn't exactly a chef at best, and his best was far behind him. Muller had brought Wilcox, Napier and Peters down to our mess with himself, to consolidate forces, and it seemed that he was serious about cooperating. But it was a little late for that.

Overhead, the fans had been stepped up to counteract the effect of staleness our minds supplied. But the whine of the motors kept reminding us our days were counted. Only Jenny was normal; she sat between Muller and Pietro, where she could watch my face and that of Napier. And even her giggles had a forced sound.

There were all kinds of things we could do—in theory. But we didn't have that kind of equipment. The plain fact was that the plants were going to lose the battle against our lungs. The carbon dioxide would increase, speeding up our breathing, and making us all seem to suffocate. The oxygen would grow thinner and thinner, once our supplies of bottled gas ran out. And eventually, the air wouldn't support life.

"It's sticky and hot," Jenny complained, suddenly.

"I stepped up the humidity and temperature controls," I told her. She nodded in quick comprehension, but I went on for Muller's benefit. "Trying to give the plants the best growing atmosphere. We'll feel just as hot and sticky when the carbon dioxide goes up, anyhow."

"It must already be up," Wilcox said. "My two canaries are breathing faster."

"Canaries," Muller said. He frowned, though he must have known of them. It was traditional to keep them in the engine-room, though the reason behind it had long since been lost. "Better kill them, Mr. Wilcox."

Wilcox jerked, and his face paled a bit. Then he nodded. "Yes, sir!"

That was when I got scared. The idea that two birds breathing could hurt our chances put things on a little too vivid a basis. Only Lomax seemed unaffected. He shoved back now, and stood up.

"Some tests I have to make, Captain. I have an idea that might turn up the killer among us!"

I had an idea he was bluffing, but I kept my mouth shut. A bluff was as good as anything else, it seemed.

At least, it was better than anything I seemed able to do. I prowled over the ship, sometimes meeting Peters doing the same, but I couldn't find a bit of evidence. The crewmen sat watching with hating eyes. And probably the rest aboard hated and feared us just as much. It wasn't hard to imagine the man who was behind it all deciding to wipe one of us out. My neck got a permanent crimp from keeping one eye behind me. But there wasn't a shred of evidence I could find.

In two more days, we began to notice the stuffiness more. My breathing went up enough to notice. Somehow, I couldn't get a full breath. And the third night, I woke up in the middle of my sleep with the feeling something was sitting on my chest; but since I'd taken to sleeping with the light on, I saw that it was just the stuffiness that was bothering me. Maybe most of it had been psychological up until then. But that was the real thing.

The nice part of it was that it wouldn't be sudden—we'd have days to get closer and closer to death; and days for each one to realize a little more that every man who wasn't breathing would make it that much easier for the rest of us. I caught myself thinking of it when I saw Bullard or Grundy.

Then trouble struck again. I was late getting to the scene this time, down by the engine room. Muller and Bill Sanderson were ahead of me, trying to separate Hal Lomax and Grundy, and not doing so well. Lomax brought up a haymaker as I arrived, and started to shout something. But Grundy was out of Muller's grasp, and up, swinging a wrench. It connected with a dull thud, and Lomax hit the floor, unconscious.

I picked Grundy up by the collar of his jacket, heaved him around and against a wall, where I could get my hand against his esophagus and start squeezing. His eyeballs popped, and the wrench dropped from his hands. When I get mad enough to act that way, I usually know I'll regret it later. This time it felt good, all the way. But Muller pushed me aside, waiting until Grundy could breathe again.

"All right," Muller said. "I hope you've got a good explanation, before I decide what to do with you."

Grundy's eyes were slitted, as if he'd been taking some of the Venus drugs. But after one long, hungry look at me, he faced the captain. "Yes, sir. This guy came down here ahead of me. Didn't think nothing of it, sir. But when he started fiddling with the panel there, I got suspicious." He pointed to the external control panel for the engine room, to be used in case of accidents. "With all that's been going on, how'd I know but maybe he was gonna dump the fuel? And then I seen he had keys. I didn't wait, sir. I jumped him. And then you come up."

Wilcox came from the background and dropped beside the still figure of Lomax. He opened the man's left hand and pulled out a bunch of keys, examining them. "Engine keys, Captain Muller. Hey—it's my set! He must have lifted them from my pocket. It looks as if Grundy's found our killer!"

"Or Lomax found him!" I pointed out. "Anybody else see this start, or know that Lomax didn't get those keys away from Grundy, when he started trouble?"

"Why, you—" Grundy began, but Wilcox cut off his run. It was a shame. I still felt like pushing the man's Adam's apple through his medulla oblongata.

"Lock them both up, until Dr. Lomax comes to," Muller ordered. "And send Dr. Napier to take care of him. I'm not jumping to any conclusions." But the look he was giving Lomax indicated that he'd already pretty well made up his mind. And the crew was positive. They drew back sullenly, staring at us like animals studying a human hunter, and they didn't like it when Peters took Grundy to lock him into his room. Muller finally chased them out, and left Wilcox and me alone.

Wilcox shrugged wryly, brushing dirt off his too-clean uniform. "While you're here, Tremaine, why not look my section over? You've been neglecting me."

I'd borrowed Muller's keys and inspected the engine room from, top to bottom the night before, but I didn't mention that. I hesitated now; to a man who grew up to be an engineer and who'd now gotten over his psychosis against space too late to start over, the engines were things better left alone. Then I remembered that I hadn't seen Wilcox's quarters, since he had the only