"Say, that's true. But we'll need the laser to cut it loose. They must have used diamond dust for the cement, too. And the fuel to get it back--"

"Harry, do me a favor. Bring--"

"That last favor cost me a three-thousand-dollar ring."

"Bring the Marsmobile out here. I want to do some digging."

"Be right there."

A minute later Henry stopped the machine alongside Chris's green suit. His smile showed that the scratches on his ring had not permanently scarred his psyche. "Where do we dig?"

Right where I'm standing."

The Marsmobile was equipped with two down-thrusting compressed-air jets for getting over steep obstructions. A large tank under the vehicle's belly held the heavily compressed air, compressed directly from the thin Martian atmosphere by the motor.

Henry turned on the jets and hovered over the spot where Chris had been standing, shifting his weight to keep the machine in place. Sand sprayed out in sheets. Chris ran to get out from under, and Henry grinned and doubled the thrust to send the fine grains showering over him. In half a minute the pressure became too low. Henry had to land.

The Marsmobile shuddered and vibrated as its motor struggled to refill the pressure chamber.

"I hate to ask," said Henry, "but what's the point of all this?"

"There's something solid down there. I want to expose it."

"Okay, if you're sure were in the right place. We've got six months of time to waste."

They wasted a few minutes silently watching the Marsmobile fill its pressure tank.

"Hey," said Henry. "You think we could stake a claim on this diamond mine?"

Chris Luden, sitting on the steep side of the dune, thoughtfully scratched the side of his helmet. "Why not? We haven't seen any live Martians, and it's for sure that n.o.body else has a claim. Sure, we'll file our claim; the worst they can do is disallow it."

"One thing. I didn't mention it before because I wanted you to see for yourself, but the heck with it. One of those blocks is covered solid with deep scratches."

"Tney all are."

"Not like these. These are deep, and they're all at forty-five degree angles, unless my imagination is fooling me. They're too fine to be sure, but I think it's some kind of writing."

And without waiting for an answer, Henry took off on the air jets. He was good at it. He was like a ballet dancer. You could see Henry shifting weight, but the scooter never seemed to move.

Something was emerging from the sand. Something not a rock.

Something like a piece of modern metal sculpture, with no use and no meaning but with a weird beauty nonetheless. Something that had been a machine and was now--nothing.

Henry Bedrosian balanced above the conical pit his jets had dug. The artifact was almost clear now. Something else showed beside it.

A mummy.

The Marsmobile settled on the last of its air. Chris plunged down the side of the pit as Henry climbed off.

The mummy was humanoid, about four feet long, with long arms, enormous fragile tapered fingers, and a traditionally oversized skull. No fine detail was visible; it had all been worn away. Chris couldn't even be sure how many fingers the--hominid--had had.

One hand still held two; the other only one, plus a flattened opposable thumb. No toes showed on the feet. The thing lay face down.

The artifact now uncovered, showed more detail. Yet the detail had no meaning. Thick bent metal bars, thin twisted wires, two enormous crumpled circles with something rotted clinging to what had been their rims --and then Henry's imagination clicked, the same visual knack that had gotten him A's in topology, and he said, "It's a bicycle."

"You've lost your mind."

"No, look. The wheels are too big, and--'

It was a fantastically distorted bicycle, with wheels eight feet across, a low, dwarf-sized saddle, and a system of gears to replace the chain. The gear ratio was very low. The saddle was almost against the rear wheel, and a tiller bar, now bent to sc.r.a.p, had been fixed to the hub of the front wheel. Something had crumpled the bicycle like a crush-proof cigarette pack in a strong man's hand, and then nitric acid rust had done its worst to the metal.

"Okay, it's a bicycle," said Chris.

"It's a Salvador Dali bicycle, but still a bicycle. They must have been a lot like us, hmmm? Bicycles, stone wells, writing--"

"Clothing."

"Where?"

"It must have been there. He's less worn around the torso, see? You can see the wrinkles in his skin. He must have been protected until his clothes rotted away."

"Maybe. He kind of ruins our lost race theory, doesn't he? He couldn't possibly be more than a couple of thousand years old. Hundreds would be more like it."

"Then he drank nitric acid after all. Well, that blows our diamond mine, partner. He's got to have living relatives."

"We can't count on their being too much like us. These things we've found--clothing, writing, wells-they're all things any intelligent being might be forced to invent. And parallel evolution might explain the biped shape."

"Parallel evolution?" Henry repeated.

"Like the eye of an octopus. If s nearly identical in structure to a human eye. Yet an octopus isn't remotely human. Most marsupials, you can't tell them from their mammal counterparts. Well, let's try to pick him up."

Any archaeologist would have shot them down m cold blood.

The mummy was as light and dry as cork, and showed no tendency to come apart in their hands. They strapped him gently over the luggage box and climbed on themselves.

Chris drove back slowly and carefully.

Chris stood on the first rung of the ladder, adjusting the mummy's balance on his left shoulder.

"We'll have to spray him with plastic before takeoff," he said.

"Do we have any plastic spray?"

"I don't remember any. We'd better take lots of pictures in case it does come apart."

"Right. There's a camera in the cabin." Chris started up, and Henry followed. They got the relic to the airlock without mishap.

"I've been thinking," said

"That nitric acid wasn't dilute, exactly, but there was water in it. Maybe this guy's chemistry can extract the water from nitric acid."

"Good thought."

They put the mummy gently on a pile of blankets and began searching for the camera.

After five frustrating minutes Chris deliberately banged his head against wall.

"I took it out to catch the sunset last night. It's in the cargo hold."

"Go get it."

Henry stood in the airlock, watching as Chris went down the ladder. After a moment in the cargo s.p.a.ce Chris started up with the camera strap over his shoulder.

"I've been thinking too," said Chris, his voice seemingly dissociated from his climbing figure.

"Diamond can't be that plentiful here, and carving it into blocks must have been real hard labor. Why diamond? And why write on a well?"

"Religious reasons? Maybe they worship water."

"That's what I was thinking."

"Of course you were. That plot's as old as Lowell.

Chris had reached the top. They squeezed into airlock and waited for it to cycle.

The door opened. Both men had their helmets off this time, and they both smelled it at once. chemical, something strong-- Thick, greasy smoke was pouring up from the ancient corpse.

Henry reacted first. He sprang for the double boiler in the small kitchen corner. The bottom half was still full of water; he s.n.a.t.c.hed it up and threw the water over the smoldering Martian mummy while with his other hand he turned on the water faucet to get more.

The mummy went off like a napalm bomb.

Henry leaped away from the exploding flames and head rammed something flat and very hard. He went down with his eyes full of leaping light. Immediately he sat up, knowing that something urgently needed doing but unable to remember what. He saw Chris, still in vacuum suit except for the helmet, run through the colored flames, pick the mummy up by the ankles and throw it into the airlock. Chris. .h.i.t the "Cycle" b.u.t.ton. The inner door swung shut.

Then Chris was bending over him.

"Where does it hurt, Harry? Can you talk? Can you move?"

Henry sat up again.

"I'm okay."

Chris expelled a gusty breath. Then he began to laugh.

Henry stood up a little shakily. His head ached. The flames in the cabin weren't intolerable, and already the air plant was whining its eagerness to make the air pure and scentless. Red smoke from the open outer airlock door blew past a porthole, dying away.

"What made him explode?" he wondered.

"The water," said Chris Luden.

"What a wild chemistry he must have! I want to be there when we meet a live one."

"But what about the well? We know he used water."

"Yes he did. He sure as h.e.l.l did. And did you know that an octopus eye is identical to a human eye?"

"Sure. But a well is a well, isn't it?"

"Not when it's a crematorium, Harry. What else could it be? There's no fire on Mars, but water must dissolve a body completely. And wouldn't I like to know what the morticians charge their customers for those cut diamond building blocks! The hardest substance known to Man or Martian! An everlasting monument to the dear departed!"

How the Heroes Die ONLY SHEER RUTHLESSNESS could have taken him out of town alive. The mob behind Carter hadn't tried to guard the Marsbuggies, since Carter would have needed too much time to take a buggy through the vehicular airlock. They could have caught him there, and they knew it. Some were guarding the personnel lock, hoping he'd try for that.

He might have; for if he could have closed the one door in their faces and opened the next, the safeties would have protected him while he went through the third and fourth and outside. On the Marsbuggy he was trapped in the bubble.

There was room to drive around in. Less than half the prefab houses had been erected so far. The rest of the bubbletown's floor was flat fused sand, empty but for scattered piles of foam-plastic walls and ceilings and floors. But they'd get him eventually. Already they were starting up another buggy.

They never expected him to run his vehicle through the bubble wall.

The Marsbuggy tilted, then righted itself. A blast of breathing-air roared out around him, picked up a cloud of fine sand, and hurled it explosively away into the thin, poisoned atmosphere. Carter grinned as he looked behind him. They would die now, all of them.

He was the only one wearing a pressure suit. In an hour he could come back and repair the rip in the bubble. He'd have to dream up a fancy story to tell when the next ship came...

Carter frowned. What were they-- At least ten wind-harried men were wrestling with the wall of a prefab house. As Carter watched, they picked the wall up off the fused sand, balanced it almost upright, and let go. The foam-plastic wall rose in the wind and slapped hard against the bubble, over the tenfoot rip.

Carter stopped his buggy to see what would happen.

n.o.body was dead. The air was not shrieking away but leaking away. Slowly, methodically, a line of men climbed into their suits and filed through the personnel lock to repair the bubble.

A buggy entered the vehicular lock. The third and last was starting to life. Carter turned his buggy and was Off.

Top speed for a Marsbuggy is about twenty-five miles per hour. The buggy rides on three wide balloon-tired wheels, each mounted at the end of a five-foot arm. What those wheels can't go over, the buggy can generally hop over on the compressed-air jet mounted underneath. The motor and the compressor are both powered by a Litton battery holding a tenth as much energy as the original Hiroshima bomb.

Carter had been careful, as careful as he had had time for. He was carrying a full load of oxygen, twelve four-hour tanks in the air bin behind him, and an extra tank rested against his knees.

His batteries were nearly full; he would be out of air long before his power ran low.

When the other buggies gave up he could circle round and return to the bubble, in the time his extra tank would give him.

His own buggy and the two behind him were the only such vehicles on Mars. At twenty-five miles per hour he fled, and at twenty-five miles per hour they followed. The closest was half a mile behind.

Carter turned on his radio.

He found the middle of a conversation.

"--Can't afford it. One of you will have to come back. We could lose two of the buggies, but not all three."

That was Shute, the bubbletown's research director and sole military man. The next voice, deep and sarcastic, belonged to Rufus Doolittle, the biochemist. "What'll we do, flip a coin?"

"Let me go," the third voice said tightly.