But, a suit that worked fine in s.p.a.ce didn"t necessarily work on other planets, unless it worked fine on the planet it was used on.

A Moon Suit isn"t a Mars Suit isn"t a Venus Suit isn"t a Triton Suit isn"t a....

Carry it on from there.

Number Three was insulated against a frigid but relatively non-corrosive atmosphere. When the pumps in the air lock began pulling out the methane-laden atmosphere, they began to bulge slightly, but not excessively. Then nitrogen, extracted from the ammonia snow that was so plentiful, filled the room, diluting the remaining inflammable gases to a harmless concentration.

Then that mixture was pumped out, to be replaced by a mixture of approximately 20 per cent oxygen and 80 per cent nitrogen--common, or garden-variety, air.

Mike the Angel cracked his helmet and sniffed. "_Guk_," he said. "If I ever faint and someone gives me smelling salts, I"ll flay him alive with a coa.r.s.e rasp."

"Yessir," said Chief Multhaus, as he began to shuck his suit. "But if I had my druthers, I"d druther you"d figure out some way to get all the ammonia out of the joints of this suit."

The other men, sniffing and coughing, agreed in att.i.tude if not in voice.

It wasn"t really as bad as they pretended; indeed, the odor of ammonia was hardly noticeable. But it made a good griping point.

The inner door opened at last, and the men straggled through.

"G"night, Chief," said Mike the Angel.

"Night, sir," said Multhaus. "See you in the morning."

"Yeah. Night." Mike trudged toward the companionway that led toward the wardroom. If Keku or Jeffers happened to be there, he"d have a quick round of _Uma ni to_. Jeffers called the game "double solitaire for three people," and Keku said it meant "horses" two heads," but Mike had simply found it as a new game to play before bedtime.

He looked forward to it.

But he had something else to do first.

Instead of hanging up his suit in the locker provided, he had bunched it under his arm--except for the helmet--and now he headed toward maintenance.

He met Ensign Vaneski just coming out, and gave him a broad smile.

"Mister Vaneski, I got troubles."

Vaneski smiled back worriedly. "Yes, sir. I guess we all do. What is it, sir?"

Mike gestured at the bundle under his arm. "I abraded the sleeve of my suit while I was working today. I wish you"d take a look at it. I"m afraid it"ll need a patch."

For a moment, Vaneski looked as though he"d suddenly developed a headache.

"I know you"re supposed to be off duty now," Mike said soothingly, "but I don"t want to get myself killed wearing a leaky suit tomorrow. I"ll help you work on it if--"

Vaneski grinned quickly. "Oh no, sir. That"ll be all right. I"ll give it a test, anyway, to check leaks. If it needs repair, it shouldn"t take too long. Bring it in, and we"ll take a look at it."

They went back into the Maintenance Section, and Vaneski spread the suit out on the worktable. There was an obvious rough spot on the right sleeve. "Looks bad," said Vaneski. "I"ll run a test right away."

"Okay," said Mike. "I"ll leave it to you. Can I pick it up in the morning?"

"I think so. If it needs a patch, we"ll have to test the patch, of course, but we should be able to finish it pretty quickly." He shrugged.

"If we can"t, sir, you"ll just have to wait. Unless you want us to start altering a suit to your measurements."

"Which would take longer?"

"Altering a suit."

"Okay. Just patch this one, then. What can I do?"

"I"ll get it out as fast as possible, sir," said Vaneski with a smile.

"Fine. I"ll see you later, then." Mike, like Cleopatra, was not p.r.o.ne to argue. He left maintenance and headed toward the wardroom for a game of _Uma ni to_. But when he met Leda Crannon going up the stairway, all thoughts of card games flitted from his mind with the careless nonchalance of a summer b.u.t.terfly.

"Hullo," he said, pulling himself up a little straighter. He was tired, but not _that_ tired.

Her smile brushed the cobwebs from his mind. But a second look told him that there was worry behind the smile.

"Hi, Mike," she said softly. "You look beat."

"I am," admitted Mike. "To a frazzle. Have I told you that I love you?"

"Once, I think. Maybe twice." Her eyes seemed to light up somewhere from far back in her head. "But enough of this mad pa.s.sion," she said. "I want an invitation to have a drink--a stiff one."

"I"ll steal Jeffers" bottle," Mike offered. "What"s the trouble?"

Her smile faded, and her eyes became grave. "I"m scared, Mike; I want to talk to you."

"Come along, then," Mike said.

Mike the Angel poured two healthy slugs of Pete Jeffers" brandy into a pair of gla.s.ses, added ice and water, and handed one to Leda Crannon with a flourish. And all the time, he kept up a steady line of gentle patter.

"It may interest you to know," he said chattily, "that the learned Mister Treadmore has been furnishing me with the most fascinating information." He lifted up his own gla.s.s and looked into its amber depths.

They were in his stateroom, and this time the door was closed--at her insistence. She had explained that she didn"t want to be overheard, even by pa.s.sing crew members.

He swizzled the ice around in his gla.s.s, still holding it up to the light. "Indeed," he rambled on, "Treadmore babbled for Heaven knows how long on the relative occurrence of parahydrogen and orthohydrogen on Eisberg." He took his eyes from the gla.s.s and looked down at the girl who was seated demurely on the edge of his bunk. Her smile was encouraging.

"He said--and I quote"--Mike"s voice a.s.sumed a gloomy, but stilted tone--"normal hydrogen gas consists of diatomic molecules. The nuclear, or proton, spin of these atoms--ah--that is, of the two atoms that compose the molecule--may be oriented in the same direction or in opposite directions."

He held a finger in the air as if to make a deep philosophical point.

"If," he said pontifically, "they are oriented in the same direction, we refer to the substance as _orthohydrogen_. If they are oriented in opposite directions, it is _parahydrogen_. The _ortho_ molecules rotate with _odd_ rotational quantum numbers, while the _para_ molecules rotate with _even_ quantum numbers.

"Since conversion does not normally occur between the two states, normal hydrogen may be considered--"

Leda Crannon, snickering, waved her hand in the air. "Please!" she interrupted. "He can"t be that bad! You make him sound like a dirge player at a Hindu funeral. What did he tell you? What did you find out?"

"_Hah!_" said Mike. "What did I find out?" His hand moved in an airy circle as he inscribed a flowing cipher with a graceful Delsarte wave.

"Nothing. In the first place, I already knew it, and in the second, it wasn"t practical information. There"s a slight difference in diffusion between the two forms, but it"s nothing to rave about." His expression became suddenly serious. "I hope your information is a bit more revealing."