That implied very strongly that the New Houston field car was also part of the hoax, planted there for the archaeologists to find. Their initial survey of Spear Canyon had found no metal bodies on that buried road; and after the storm that had trapped the archaeologists in their tents, tracks had been found in the snow to the north that no one was ever able to explain. So it looked as though the car had been placed there during the storm. But there was still a storm of controversy raging over that point, back on Mars. The journal of Emma Weil — part of the hoax! — had been dated to the mid-twenty-third century, the time of the revolution — or so it was claimed. Others contested that, and still others attacked the authenticity of the car itself, of the weathering of its surface, of the secondary documents found in it, of the likelihood of the slide that had revealed it… From every angle conceivable the field car and the entire Davydov theory was challenged, and found lacking, and poor Nederland ran around Mars like the Dutch boy, poking his fingers in the holes of a dike that was about to collapse entirely. The Davydov expedition was a fiction. There never had been any Mars Starship Association. It was all a giant hoax.

Bitterly I kicked the plaque. It was set solidly. I picked up a double handful of regolith, dumped it on the marker. Several handfuls made a good pile; it looked like a cairn of pebbles, set on a big flat boulder. “Stupid romantic story,” I muttered.

“Preying on what we want to believe…” Why had she done it?

My only regular companion during these off hours’ meditations was Jones. It was natural that he should prefer these times, for only then did the monument fully regain its solitary power, its shadowed majesty. But I thought, also, that he felt self-conscious doing his work before the others.

For work he was doing, laboriously and painstakingly, with a surveying distance gun. He was measuring the megalith. When I switched to the common band on the intercom, I heard him muttering numbers to himself, and humming snatches of music. He had arranged to have music piped in to him from the landing vehicles while he worked; usually when I switched to that band one of Brahms’s symphonies was playing.

Occasionally he enlisted my aid. He would stand at a lith and aim his gun at me while I held a small mirror before a lith; then I walked to the next lith, and repeated the operation. I laughed at the tiny figure across the central crater.

“Sixty-six times sixty-six, that’s a lot of measurements,” I said. “Just what do you think you’re doing?”

“Numbers,” he replied. “Whoever built this was very very careful about numbers. I want to see if I can find the lith by looking very carefully at the numbers that are made by the monument.”

“The lith?”

“The patterns are singling out a particular lith, I feel.”

“Ah.”

“Therefore I must try to find the unit of measurement they used when building. Note that it was not metrical or foot and inch. Long ago a man named Alexander Thorn discovered that all of the stone megaliths in northern Europe used the same unit, which he called the megalithic yard. It was about seventy-four centimeters,” He stopped what he was doing, and I saw the tiny red dot of his gun wander over the liths to my left. “Now, no one but me has ever noticed that this megalithic yard from northern Europe is almost exactly the same length as the ancient Tibetan unit—”

“And the Egyptian unit used at the Pyramids, undoubtedly, but isn’t that because they’re the standard elbow to finger units of early civilizations?”

“Maybe, maybe. But since the flattened ring construction here is one of the common patterns for British henges, I thought I’d check to see.”

“How is it coming along?”

“I don’t know yet.”

I laughed. “You could find out in seconds on the Snowflake’s computer.”

“Yeah?”

“I’m glad you’re here with us, Jones, I really am.”

He chuckled. “You like having someone here crazier than you. But just wait. The numerology of Icehenge was always a rich field, even before these new measurements I’m taking. Did you know that if you begin at the Fallen Lith and count counterclockwise by prime numbers, the width of each lith increases by one point two three four times? Or that the heights of each foursome of consecutive liths add up to either ninety-five point four, or one hundred and one meters? Or that each length divided by width ends with a prime number—”

“Who says all this?”

“I do. You must not have read my book, Mathematics and Metaphysics At Icehenge.”

“I missed that one, I guess.”

“One of my best. See how much you don’t know?”

In this manner several weeks quickly passed. Brinston’s face took on a slightly anxious expression, though he was finding out some interesting things. It appeared that for every lith a large cylindrical posthole had been dug — the ice beam had been positioned on the floor of the hole, which was invariably bedrock, and the hole was then filled. The only other fact they had discovered was that there were no individual postholes for the Six Great Liths. Perhaps because they were so near each other, a single big hole, still cylindrical, had been dug for all of them. Brinston’s team had marked out the circumference of this cylinder, and it encompassed nine liths. “But I don’t know what it means,” he confessed irritably.

The day Brinston presented this information, Jones and I walked out to the site. Jones was excited, but he wouldn’t tell me why.

It was after the working hours, and we were the only ones out there. We walked through the circle of towers and on to the pole, to watch the henge from there. Dr. Grosjean had had a short metal pole placed at the axis of rotation to help his first survey of the site, and it stood there still, a little less than shoulder high. We sat on either side of it. The sun was on the other side of the megalith, and the liths were more obscure than ever — faint reverse shadows, dim areas of lightness against the pervading black. The gravel underneath me felt cold.

“Now we’re spinning like a top,” said Jones. “Feel it?” I laughed easily, yet as we sat there I could suddenly visualize Pluto as a tiny twirling ball, a handful of ice toothpicks stuck in its top, two antlike creatures seated on the axis of rotation.

I moved and the sun disappeared behind a lith. I felt the ancient fear — eclipse, sun death.

After a long silence Jones took his distance gun from his suit’s thigh pocket and turned it on. He pointed it at the henge. On lith number three, the tallest one, a red spot appeared, brighter than the sun. Jones moved the spot in a small circle on the lith.

“That one,” he said. “There’s something special about lith three.”

“Aside from it being the tallest?”

“Yes.” He jumped up and took off rapidly toward it. “Come on!”

I hurried alter him. As we approached it, he said, “I told you I would find something in those measurements. Though it wasn’t exactly what I had expected.”

We stopped before it, standing just outside the arc of the Six Great Liths. Number three was massive, endlessly tall, big as a Martian skyscraper. On this side it was in total darkness, or rather, was illuminated only by starlight, which was barely adequate for our vision; the circle of shadows reared up into eerie obscurity. We stared up into it.

“If you take the centerpoint of the lith,” Jones said, “at ground level, and measure from there. Then every center of every lith in the henge is an exact multiple of the megalithic yard away.”

“You’re kidding.”

“No, seriously. It doesn’t work for any other lith, either.”

I looked up at his faceplate, but it was too dark — from a meter or two away I could barely see him. “You used the computers.”