The soil berm was dotted by pale green rosettes of tiny grass blades. Longer blades stood in clumps here and there. Most of the taller blades were dead, and light gray. Right next to the pond were patches of dark green succulent leaves, dark red at their edges. Where the green shaded into red was a color he couldn’t name, a dark lustrous brown stuffed somehow with both its constituent colors. He would have to call up a color chart soon, it seemed; lately when looking around outdoors he found that a color chart came in handy about once a minute. Waxy almost-white flowers were tucked under some of these bicolored leaves. Farther on lay some tangles, red-stalked, green-needled, like beached seaweed in miniature. Again that intermixture of red and green, right there in nature staring at him.

A distant wind-washed hum; perhaps the harping rocks, perhaps the buzz of insects. Black midges, bees … in this air they would only have to sustain about thirty millibars of CO₂, because there was so little partial pressure driving it into them, and at some point internal saturation was enough to hold any more out. For mammals that might not work so well. But they might be able to sustain twenty millibars, and with plant life flourishing all over the planet’s lower elevations, CO₂ levels might drop to twenty millibars fairly soon; and then they could dispense with the air tanks and the face masks. Set loose animals on Mars.

In the faint hum of the air he seemed to hear their voices, immanent or emergent, coming in the next great surge of viriditas. The hum of distant voices; the wind; the peace of this little pool on its rocky moor; the Nirgalish pleasure he took in the sharp cold… “Ann should see this,” he murmured.

Then again, with the space mirrors gone, presumably everything he saw here was doomed. This was the upper limit of the biosphere, and surely with the loss of light and heat the upper limit would drop, at least temporarily, perhaps for good. He didn’t like that; and it seemed possible there might be ways to compensate for the lost light. After all, the terraforming had been doing quite well before the mirrors’ arrival; they hadn’t been necessary. And it was good not to depend on something so fragile, and better to be rid of it now rather than later, when large animal populations might have died in the setback along with the plants.

Even so it was a shame. But the dead plant matter would only be more fertilizer in the end, and without the same kind of suffering as animals. At least so he assumed. Who knew how plants felt? When you looked closely at them, glowing in all their detailed articulation like complex crystals, they were as mysterious as any other life. And now their presence here made the entire plain, everything he could see, into one great fellfield, spreading in a slow tapestry over the rock; breaking down the weathered minerals, melding with them to make the first soils. A very slow process. There was a vast complexity in every pinch of soil; and the look of this fellfield was the loveliest thing he had ever seen.

To weather. This whole world was weathering. The first printed use of the word with that meaning had appeared in a book on Stonehenge, appropriately enough, in 1665. “The weathering of so many Centuries of Years.” On this stone world. Weathering. Language as the first science, exact yet vague, or multivalent. Throwing things together. The mind as weather. Or being weathered.

There were clouds coming up over the nearby hillocks to the west, their bottoms resting on a thermal layer as levelly as if pressing down on glass. Streamers like spun wool led the way east.

Sax stood up and climbed out of the pool’s depression. Out of the shelter of the hole, the wind was shockingly strong — in it the cold intensified as if an ice age had struck full force that very second. Windchill factor, of course; if the temperature was 262 K, and the wind was blowing at about seventy kilometers an hour, with gusts much stronger, then the windchill factor would create a temperature equivalent of about 250 K. Was that right? That was very cold indeed to be out without a helmet. And in fact his hands were going numb. His feet as well. And his face was already without feeling, like a thick mask at the front of his head. He was shivering, and his blinks tended to stick together; his tears were freezing. He needed to get back to his car.

He plodded over the rockscape, amazed at the power of the wind to intensify cold. He had not experienced wind-chill like this since childhood, if then, and had forgotten how frigid one became. Staggering in the blasts, he climbed onto a low swell of the ancient lava and looked upslope. There was his rover — big, vivid green, gleaming like a spaceship — about two kilometers up the slope. A very welcome sight.

But now snow began to fly horizontally past him, giving a dramatic demonstration of the wind’s great speed. Little granular pellets clicked against his goggles. He took off toward the rover, keeping his head down and watching the snow swirl over the rocks. There was so much snow in the air that he thought his goggles were fogging up, but after a painfully cold operation to wipe the insides, it became clear that the condensation was actually out in the air. Fine snow, mist, dust, it was hard to tell.

He plodded on. The next time he looked up, the air was so thick with snow that he couldn’t see all the way to the rover. Nothing to do but press on. It was lucky the suit was well insulated and sewn through with heating elements, because even with the heat on at its highest power, the cold was cutting against his left side as if he were naked to the blast. Visibility extended now something like twenty meters, shifting rapidly depending on how much snow was passing by at the moment; he was in an amorphously expanding and contracting bubble of whiteness, which itself was shot through with flying snow, and what appeared to be a kind of frozen fog or mist. It seemed likely he was in the storm cloud itself. His legs were stiff. He wrapped his arms around his torso, his gloved hands trapped in his armpits. There was no obvious way of telling if he was still walking in the right direction. It seemed like he was on the same course he had been when visibility had collapsed, but it also seemed like he had gone a long way toward the rover.

There were no compasses on Mars; there were, however, APS systems in his wristpad and back in the car. He could call up a detailed map on his wristpad and then locate himself and his car on it; then walk for a while and track his positions; then make his way directly toward the car. That seemed like a great deal of work — which brought it to him that his thinking, like his body, was being affected by the cold. It wasn’t that much work, after all…

So he crouched down in the lee of a boulder and tried the method. The theory behind it was obviously sound, but the instrumentation left something to be desired; the wristpad’s screen was only five centimeters across, so small that he couldn’t see the dots on it at all well. Finally he spotted them, walked awhile, and took another fix. But unfortunately his results indicated that he should be hiking at about a right angle to the direction he had been going.

This was unnerving to the point of paralysis. His body insisted that it had been going the right way; his mind (part of it, anyway) was pretty certain that it was better to trust the results on the wristpad, and assume that he had gotten off course somewhere. But it didn’t feel that way; the ground was still at a slope that supported the feeling in his body. The contradiction was so intense that he suffered a wave of nausea, the internal torque twisting him until it actually hurt to stand, as if every cell in his body was twisting to the side against the pressure of what the wristpad was telling him — the physiological effects of a purely cognitive dissonance, it was amazing. It almost made one believe in the existence of an internal magnet in the body, as in the pineal glands of migrating birds — but there was no magnetic field to speak of. Perhaps his skin was sensitive to solar radiation to the point of being able to pinpoint the sun’s location, even when the sky was a thick dark gray everywhere. It had to be something like that, because the feeling that he was properly oriented was so strong!