The Magellan hung in the air while the men studied the surface of this world that had so long been a mystery. The air was not the clear air of Earth; rather, it was the kind that precedes the coming of a fog, thick, heavy with moisture, the horizons fading into gray. Below them lay a mottled expanse of water, reflecting the gray sky, and verging almost to a deep brown. The water was still, occasionally stirred by a slight wave. "No tides have ever moved these waters," commented Russ quietly to Burl. "There is no moon to pull and sway them. The motion of this world, so slow in the passage of its day, hardly disturbs the water."

"It looks shallow to me," said Burl. "The darker sections look as if the bottom must be close."

"I imagine it is. We'll take soundings," Russ answered. "I have a feeling the whole world may be like this ... one vast, shallow, swampy sea. See the scum floating on it?"

"See it? Now that you mention it, there's hardly a part that hasn't something on it," was Burl's reply. "There're patches of muck all over it, like floating oil, or even drifting masses of weeds."

It was true. The water showed on its surface a strange filth unlike anything one would expect on the surface of a Terrestrial sea. There were wide areas of brownish-gray slime and little floating blobs of green. Shining flecks of yellow, like bright oil drops, seemed to flow through and between the masses of scum.

At the radar, Haines began to call out figures. As Russ had guessed, it was a shallow sea. In places, the bottom was only a dozen feet beneath. For a while, all the men of the crew were quiet, watching the silent waters beneath them.

"Unclean, the whole place looks unclean," Lockhart said finally. "We've got work to do. Let's find the Sun-tap station."

The rest of the crew came to action. The spaceship began to move slowly, while Oberfield and Caton probed for the lines of force which would lead to the station.

Now a long, low bank appeared, a ridge of mud protruding above the water. Here and there stretched other low mud bars, and once a ridge of rock.

"I've seen no animals or birds," said Burl. "Do you suppose there are any?"

Russ pursed his lips. "I don't think so. From the look of this world, life probably isn't developed that far. You won't find animals until there is dry land—and I'd guess now that there's no place on all Venus where there is much dry land. There may be fish or fish life, but even that's questionable. Consider—the long, long day, the absence of violent, unshielded Sun rays, the steady damp warmth, the quiet, barely moving waters, the heavy amounts of carbon dioxide in the air...."

He paused and went over to Lockhart's chart table to pick up a paper. "Oberfield worked out the atmosphere. It is very heavy in carbon dioxide, very low in free oxygen. There's water vapor down here, but the clouds have kept it below; it didn't show up in the outer atmosphere at all."

"There's the Sun-tap base," said Burl, and added as an afterthought, "I think."

This one did not look at all like the other stations he had seen. There was indeed a ringed wall station, but the wall was low and slanted outward. It stood on the end of a wide mudbank, and near it veins of rock glistened as if wet.

The interior machinery was a neat, compact mass of crystalline globes and levers. But the masts and shining discs which had characterized the stations on Mercury and Earth were missing. Instead, there floated upon the surface of the water, for a mile around, great shining bowls, like huge saucers gently rocking in the faint wavelets. Thin, flexible, shining lines of metal connected this surface layout with the station.

"With no direct Sun to aim at, this station seems to be directed toward a nonfocused system of light diversion," Lockhart announced. "The wrecking crew please get under way!"

"I'm going down with you," Russ joined in. "I've gotten permission to take some observations from the surface."

"Good," said Burl, and hurried with him down to the central floor.

They disembarked in two parties. Haines and Ferrati used the two-man rocket plane and would make a wide encirclement of the vicinity, mapping and finally blowing up the accumulator discs floating on the surface. Burl, Russ, and Boulton took a helicopter.

The helicopter, under the control of the Marine captain, dropped out of the cargo port of the Magellan. Steadied by the regular whirl of its great blades and driven by tiny rocket jets in the tip of each wing, the whirlybird swung down like a huge mosquito hovering over a swamp patch.

It moved over the water and finally hung directly over the mudbank. Maneuvering so that the helicopter was directly in the protected circle of the walls, Burl and Russ dropped a rope ladder and swung down hand over hand to be the first human beings to set foot on Venus.

They were lightly dressed, for the temperature was hot, around 110°, and it was humid. No breezes blew here. They wore shorts and shirts and high-laced leather boots. Each carried two small tanks of oxygen on his back. A leather mouth nozzle strapped across the shoulders guaranteed a steady flow of breathable air. In their belts were strapped knives and army pistols. Russ carried recording equipment, and Burl a hatchet.

They dropped off the swaying ladder inside the station. The ground was hard-packed as if the builders had beaten it down and smoothed it off. The globes were familiar to Burl—he had studied the pictures of the two he had already visited and he realized that they followed the same general system. Where the mast towers would have been, there were leads running through the plastic walls out across the sea. He wondered briefly why the walls were curved outward.

As the helicopter moved away, the metal weight on the end of the dangling ladder brushed the top of the wall. There was a crackling noise, and a spark jumped between them.

"The wall is electrically charged," said Burl. "I wonder why?"

Russ shook his head. "From the looks of it, to keep off something. Perhaps some kind of native life. But what? I'm sure there's nothing of a highly organized physical structure here."

Burl found the controls of the station, but before touching them, he remembered the alarm on Mercury. "I'd better try to smash the alarm first," he called out to Russ.

Finally, Burl located an isolated globe perched on a post, which resembled the one he had briefly glimpsed on Mercury. He ran his hands over it, feeling a mild vibration within. Then, at its base, he found the levers. He moved them and the vibration died out. "I think I've turned it off," he announced. "But stand by with a gun, just in case."

Russ drew his pistol, and Burl switched off the main controls of the Sun-tap. A globe or two burst; there was a sort of settling down in the station. Abruptly they felt the heat intensify and knew that the sky was shining more brilliantly than before. The diversion of the Sun was over for Venus.

The alarm globe remained quiet, but Burl took his hatchet and smashed it. Russ was carefully photographing the station, measuring the distances, and tracing the lines. Overhead, the wide blades of the helicopter flapped around and around, accompanied by little hissing puffs of rocket smoke. They could see Boulton looking down at them from the tiny cabin.

Russ was scooping up bits of soil to bring back for analysis when he saw what seemed to be a wet patch on top of the wall. As he watched, it spread until it reached the bottom. In a remarkably short time a whole section of wall was gleaming wet. A patch of damp oiliness spread over the floor.

"This I've got to get a sample of," said the rusty-haired astronomer. He reached for a sampling bottle in his pocket, and at the same time the patch of wetness spread to his shoes.

As Russ stepped forward, there was a sucking sound, and he lifted a thick gummy mass that was stuck to his sole. He shook his foot, set it down, and lifted the other, but it, too, was imbedded in thick slime. The stuff now was running up his ankle.

"Hey!" he called out, and swung one foot vigorously to free it. More swiftly than he could move, the whole patch slid down the wall and swept around him. It was moving up his legs, as if trying to envelop him.

"It's alive!" he shouted, and grabbed for the knife in his belt. In vain he tried to slash out. "It's like a giant amoeba that engulfs its food! Get it off me!"

But the knife was ineffective. He fired his pistol, but the thing was just a vast wide puddle of slime, without brain, heart or organ that could be harmed. The soles of Russ's boots were already half eaten away and his socks were going fast. Some of it was touching the skin of his knees.

He screamed as the stuff burned him.

Burl had joined the attack with his knife, but leaped back when that proved useless. His mind raced for a way to help. Above them, Boulton was swinging the helicopter down so Russ could hoist himself out of harm's way, but time would not permit it. In another instant the mass would have Russ.

Burl grabbed at the straps crossing his shoulder and swung the two oxygen tanks from his back. He snatched one from its leather holster, and pointed its nozzle at the mass of slime. He turned the stream of oxygen on, and then, taking his pistol, held its muzzle in the jet of oxygen and fired it.

The roar of the gun was matched by the roar of a stream of fire that shot from the tank. Wherever the burning jet of oxygen touched, the mass shriveled and blackened. Yards and yards of amoeba seemed to writhe, hump upward in agony, and pull away.

There was a ring of burned white along the ground, a sickening smell in the air, but the thing was dead.

Russell Clyde grabbed the ladder as it swung toward him, and climbed up. The soles of his boots were gone and the sides were strings of raw, half-eaten leather. His legs and knees bore ugly patches of red where the slime had touched.

"Well done!" called Boulton to Burl from the cabin. "Come on up before something else comes along!"

Burl grabbed the ladder. He took two steps on the swaying, swinging rope as the helicopter started to climb and suddenly he felt himself losing strength. He became dizzy and tried to hold on, but began to lose consciousness. Dimly he heard Boulton yell at him, "The oxygen, the other tank, turn it on!"

The second tank was still dangling from his chest.

Fighting for consciousness, Burl twisted the nozzle. There was a hiss and he felt air blow against him. Miraculously, his senses cleared, and holding the oxygen tank tight against him, he climbed up the ladder and into the safety of the helicopter.