Morey punched figures into the calculator. "Wow! Somewhere in the neighborhood of a hundred days, using all the acceleration that will be safe! At five gravities, reducing our present velocity of twenty-five thousand miles per second to zero will take approximately twenty-four hundred hours--one hundred days! We'll have to use the gravitational attraction of that sun to help us."

"We'll have to use the s.p.a.ce control," said Arcot. "If we move close to the sun by the s.p.a.ce control, all the energy of the fall will be used in overcoming the s.p.a.ce-strain coil's field, and thus prevent our falling.

When we start to move away again, we will be climbing against that gravity, which will aid us in stopping. But even so, it will take us about three days to stop. We wouldn't get anywhere using molecular power; that giant sun was just too d.a.m.ned generous with his energy of fall!"

They started the cycles, and, as Arcot had predicted, they took a full three days of constant slowing to accomplish their purpose, burning up nearly three tons of matter in doing so. They were constantly oppressed by a load of five gravities except for the short intervals when they stopped to eat and when they were moving in the s.p.a.ce control field.

Even in sleeping, they were forced to stand the load.

The ma.s.sive sun was their princ.i.p.al and most effective brake. At no time did they go more than a few dozen million miles from the primary, for the more intense the gravity, the better effect they got.

Morey divided his time between piloting the ship while Arcot rested, and observing the system. By the end of the third day, he had made very creditable progress with his map.

He had located only six planets, but he was certain there were others.

For the sake of simplicity, he had a.s.sumed circular orbits and calculated their approximate orbital velocities from their distance from the sun. He had determined the ma.s.s of the sun from direct weighings aboard their ship. He soon had a fair diagram of the system constructed mathematically, and experimental observation showed it to be a very close approximation.

The planets were rather more ma.s.sive than those of Sol. The innermost planet had a third again the diameter of Mercury and was four million miles farther from the primary. He named it Hermes. The next one, which he named Aphrodite, the Greek G.o.ddess corresponding to the Roman Venus, was only a little larger than Venus and was some eight million miles farther from its primary--seventy-five million miles from the central sun.

The next, which Morey called Terra, was very much like Earth. At a distance of a hundred and twenty-four million miles from the sun, it must have received almost the same amount of heat that Earth does, for this sun was considerably brighter than Sol.

Terra was eight thousand two hundred miles in diameter, with a fairly clear atmosphere and a varying albedo which indicated clouds in the atmosphere. Morey had every reason to believe that it might be inhabited, but he had no proof because his photographs were consistently poor due to the glare of the sun.

The rest of the planets proved to be of little interest. In the place where, according to Bode's Law, another planet, corresponding to Mars, should have been, there was only a belt of asteroids. Beyond this was still another belt. And on the other side of the double asteroid belt was the fourth planet, a fifty-thousand-mile-in-diameter methane-ammonia giant which Morey named Zeus in honor of Jupiter.

He had picked up a couple of others on his plates, but he had not been able to tell anything about them as yet. In any case, the planets Aphrodite and Terra were by far the most interesting.

"I think we picked the right angle to come into this system," said Arcot, looking at Morey's photographs of the wide bands of asteroids.

They had come into the planetary group at right angles to the plane of the ecliptic, which had allowed them to miss both asteroid belts.

They started moving toward the planet Terra, reaching their objective in less than three hours.

The globe beneath them was lit brightly, for they had approached it from the daylight side. Below them, they could see wide, green plains and gently rolling mountains, and in a great cleft in one of the mountain ranges was a shimmering lake of clearest blue.

The air of the planet screamed about them as they dropped down, and the roar in the loudspeaker grew to a mighty cataract of sound. Morey turned down the volume.

The sparkling little lake pa.s.sed beneath them as they shot on, seventy-five miles above the surface of the planet. When they had first entered the atmosphere, they had the impression of looking down on a vast, inverted bowl whose edge rested on a vast, smooth table of deep violet velvet. But as they dropped and the violet became bluer and bluer, they experienced the strange optical illusion of "flopping" of the scene. The bowl seemed to turn itself inside out, and they were looking down at its inner surface.

They shot over a mountain range, and a vast plain spread out before them. Here and there, in the far distance, they could see darker spots caused by buckled geological strata.

Arcot swung the ship around, and they saw the vast horizon swing about them as their sensation of "down" changed with the acceleration of the turn. They felt nearly weightless, for they were lifting again in a high arc.

Arcot was heading back toward the mountains they had pa.s.sed over. He dropped the ship again, and the foothills seemed to rise to meet them.

"I'm heading for that lake," Arcot explained. "It seems absolutely deserted, and there are some things we want to do. I haven't had any decent exercise for the past two weeks, except for straining under high gravity. I want to do some swimming, and we need to distill some water for drink; we need to refill the tanks in case of emergencies. If the atmosphere contains oxygen, fine; if it doesn't, we can get it out of the water by electrolysis.

"But I hope that air is good to breathe, because I've been wanting a swim and a sun bath for a long time!"

XIII

The _Ancient Mariner_ hung high in the air, poised twenty-five miles above the surface of the little lake. Wade, as chemist, tested the air while the others readied the distillation and air condensation apparatus. By the time they had finished, Wade was ready with his report.

"Air pressure about 20 psi at the surface; temperature around ninety-five Fahrenheit. Composition: eighteen percent oxygen, seventy-five percent nitrogen, four-tenths of one percent carbon dioxide, residue--inert ga.s.ses. That's not including water vapor, of which there is a fair amount.

"I put a canary into the air, and the bird liked it, so I imagine it's quite safe except for bacteria, perhaps. Naturally, at this alt.i.tude the air is germ-free."

"Good," said Morey, "then we can take our swim and work without worrying about s.p.a.cesuits."

"Just a minute!" Fuller objected. "What about those germs Wade mentioned? If you think I'm going out in my shorts where some flock of bacteria can get at my tender anatomy, you've got another think coming!"

"I wouldn't worry about it," Wade said. "The chances of organisms developing along the same evolutionary line is quite slim. We may find the inhabitants of the same shape as those of another world, because the human body is fairly well constructed anatomically. The head is in a place where it will be able to see over a wide area and it's in a safe place. The hand is very useful and can be improved upon but little.

True, the Venerians have a second thumb, but the principle is the same.

"But chemically, the bodies are probably very different. The people of Venus are widely different chemically; the bacteria that can make a Venerian deathly ill is killed the instant it enters our body, or else it starves to death because it can't find the kind of chemical food it needs to live. And the same thing happens when a Venerian is attacked by an Earthly microorganism.

"Even on Earth, evolution has produced such widely varying types of life that an organism that can feed on one is totally incapable of feeding on another. You, for instance, couldn't catch tobacco mosaic virus, and the tobacco plant can't catch the measles virus.

"You couldn't expect a microorganism to evolve here that was capable of feeding on Earth-type tissues; they would have starved to death long ago."

"What about bigger animals?" Fuller asked cautiously.

"That's different. You would probably be indigestible to an alien carnivore, but he'd probably kill you first to find out. If he ate you, it might kill him in the end, but that would be small consolation.

That's why we're going to go out armed."

Arcot dropped the ship swiftly until they were hovering a bare hundred feet over the waters of the lake. There was a little stream winding its way down the mountainside, and another which led the clear overflow away.

"I doubt if there's anything of great size in that lake," Arcot said slowly and thoughtfully. "Still, even small fish might be deadly. Let's play safe and remove all forms of life, bacterial and otherwise. A little touch of the molecular motion ray, greatly diffused, will do the trick."

Since the molecular ray directed the motion of the molecules of matter, it prevented chemical reactions from taking place, even when greatly diffused; all the molecules tend to go in the same direction to such an extent that the delicate balance of chemical reactions that is life is upset. It is too delicate a thing to stand any power that upsets the reactions so violently. All things are killed instantly.

As the light haze of the ionized air below them glowed out in a huge cone, the water of the lake heaved and seemed to move in its depths, but there was no great movement of the waters; they lost only a fraction of their weight. But every living thing in that lake died instantly.

Arcot turned the ship, and the shining hull glided softly over to one side of the lake where a little sandy beach invited them. There seemed no indication of intelligent life about.

Each of them took a load of the supplies they had brought, and carried them out under the shade of an immense pine-like tree--a gigantic column of wood that stretched far into the sky to lose its green leaves in a waving sea of foliage. The mottled sunlight of the bright star above them made them feel very much at home. Its color, intensity, and warmth were all exactly the same as on Earth.

Each of the men wore his power suit to aid in carrying the things they had brought, for the gravity here was a bit higher than that of Earth.

The difference in air pressure was so little as to be scarcely noticeable; they even adjusted the interior of the ship to it.

They had every intention of staying here for awhile. It was pleasant to lie in the warm sun once more; so pleasant that it became difficult to remember that they were countless trillions of long miles from their own home planet. It was hard to realize that the warm, blazing star above them was not Old Sol.

Arcot was carrying a load of food in a box. He had neutralized his weight until, load and all, he weighed about a hundred pounds. This was necessary in order to permit him to drag a length of hose behind him toward the water, so it could be used as an intake for the pumps.

Morey, meanwhile, was having trouble. He had been carrying a load of a.s.sorted things to use--a few pneumatic pillows, a heavy iron pot for boiling the water, and a number of other things.

He reached his destination, having floated the hundred or so feet from the ship by using his power suit. He forgot, momentarily, and dropped his load. Immediately, he too began to "drop"--upward! He had a buoyancy of around three hundred pounds, and a weight of only two fifty.

In dropping the load, the sudden release had caused the power unit to jerk him upward, and somehow the controlling k.n.o.b on the power pack was torn loose.