"Yes. Odd. But they could still be man made."
"In this air? Breathing nitric acid, drinking red fuming nitric acid? But--" Chris drew a deep breath.
"Why complain? It's life, Harry! We've discovered intelligent life!"
"Weve got to tell Abe."
"Right."
But it was a long moment before either moved. They stood leaning over the well, vivid green pressure suits against pink sand and dark red horizon, peering down into the blur of darkness at the bottom. Then they turned and mounted the Marsmobile.
The landing vehicle stood like an upright steel ball- point pen. Its bottom half was three spreading legs, a restarting solid rocket, and a spacious cargo hold, two- thirds empty now. The upper half was the return-to-orbit stage. Far away across the crescent dunes was a white patch, the jettisoned drag chute.
The Marsmobile, a glorified two-seater motorcycle with big round tires and a number of special modifications, putt-putted up to a landing leg and stopped. Henry got off and climbed to the cabin to call Abe Cooper in the orbiter. Chris Luden mounted to the cargo hold and rummaged through a disorganized hash of necessities until he had a long coil of thin line, a metal bucket, and a heavy rock hammer, all treated to resist the corrosive atmosphere. He dropped the objects next to the Marsmobile and climbed down.
"Now we'll see," he told himself.
Henry descended the ladder.
"Abe's having kittens," he reported.
"He says if we don't call him every five minutes he'll come down after us. He wants to know, how old is the well?"
"So do I." Chris brandished the hammer.
"We'll knock a chip off and analyze it. Let's go."
The well was a mile and a half from the ship, and not of a conspicuous color. Probably they would have lost it if they hadn't left a flag to mark it.
"Let's see how deep it is first," said Luden. He put the hammer in the bucket for a weight, tied a line to the handle and let it fall. In the eery silence of the Martian desert they waited, listening... The rope was nearly gone when the bucket struck something. In a moment the ghost of a splash came floating up from the depths. Henry marked the line so they could measure how deep it had gone. It looked about three hundred feet. They hauled it up.
The bucket was half full of a cloudy, slightly oily fluid.
Chris handed it to his partner.
"Harry, you want to take this back and analyze it?"
Henry's dark face grinned around the pointed beard. "I'll match you for it. We both know what it's gonna be."
"Sure, but it has to be done. Even." They matcbed fingers. Henry lost. He rode back to the ship, the bucket dangling from one hand, fluid slopping over the edge.
The stone which formed the well might have been quartz, or even some kind of unveined marble. It had been too badly weathered, too finely scored and polished and etched by the patient sand grains, to tell what it was. Chris Luden picked a likely looking block and brought the hammer down hard on what seemed to be a crack. He did it three times.
The hammer was ruined.
Luden shifted the hammer this way and that to examine the uneven, dulled edge and flattened corners. His blue eyes held a puzzled look. He knew the government might have quibbled about the weight of a tool for the Mars Project, but never the cost or quality. Here on Mars that hammer was worth tens of thousands of dollars. It must be made of some hard, durable steel alloy. Then--
He cocked his head in his helmet, tasting a strange idea...
"Harry!"
"Yeah?"
"How you doing?"
"I'm just coming in the airlock. Give me five minutes to flnd out that this stuff is nitric acid."
"Okay, but do me a favor. Have you got your ring?"
"The diamond horseshoe? Sure."
"Bring it back with you, outside your suit. Outside, that is."
"Now wait a minute, Chris. That's a valuable ring. Why not use your own?"
"I should have thought of that! I'll just take off my pressure suit and-Uh! Can't seem to got my helmet unfastened--"
"Stop! Stop! I get the point." There was a click as Henry's radio-went off.
Luden sat down to wait.
The sun was sliding toward the horizon. They had landed shortly before sunset yesterday, so they knew how suddenly the desert could turn from pink to midnight black, and how little light the insignificant moons gave. But sundown was four hours away.
The dunes all faced the same way, perfect crescents, as regular as if hand-made. Something must shape the winds here, causing them to blow always in one direction, like Earth's trade winds. And the dunes would crawl across the sands, slower than snails, following the winds.
How old were the stones against his back? If they were really--a strange and silly thought, but Chris wouldn't have volunteered for the Mars Project if he were not half a romantic--if they were really diamond, they must be terribly old, to be so worn by mere sand. Far older than the pyramids, and revered ancestor to the Sphinx. Maybe the race that carved those stones had since perished. Science-fiction writers often assumed an extinct Martian race. Why, perhaps the well had originally held water--
"Hello, Chris?"
"Here."
"It's dirty nitric acid, not too strong. Next time you'll believe me."
"Harry, they didn't send us here to make astute guesses. They did all the guessing when they built the ship. We came to find out for sure, right? Right."
"See you in ten minutes." Click.
Luden let his eyes drift back across the desert. It was a moment before he realized what had caught his eye. One of the dunes was irregular. The curves were wrong, asymmetrical. The normal crescent had left one sprawling, trailing arm. It stood out like a pear in a line of apples.
He had ten minutes, and the dune wasn't far. Luden got up and started walking.
He stood under the dune and looked back. The well was clearly visible. The distance was even shorter than he had thought. He had been deceived by the nearness of the horizon.
The lip of the dune was some fourteen feet high.
What had distorted it? An upthrusting spire of rock, perhaps, not quite high enough to show through the sand. They could find it with the sonar later.
It had to be under the one sprawling, twisted arm of sand.
