"No, it doesn't," said Denison, sulkily. "It looks like a cliff to me."
"Nonsense. Now listen to me and remember what I told you. Keep your feet about six inches apart and one just a few inches ahead of the other. It doesn't matter which one is ahead. Keep your knees bent. Don't lean into the wind because there isn't any. Don't try to look up or back, but you can look from side to side if you have to. Most of all, when you finally hit level, don't try to stop too soon; you'll be going faster than you think. Just let the glider expire and then friction will bring you to a slow halt."
"I'll never remember all that."
"Yes, you will. And I'll be right at your side to help. And if you do fall and I don't catch you, don't try to do anything. Just relax and let yourself tumble or slide. There are no boulders anywhere that you can collide with."
Denison swallowed and looked ahead. The southward slide was gleaming in Earthlight. Minute unevenness caught more than their share of light, leaving tiny uphill patches in darkness so that there was a vague mottling of the surface. The bulging half-circle of Earth rode the black sky almost directly ahead.
"Ready?" said Selene. Her gauntleted hand was between his shoulders.
"Ready," said Denison faintly.
"Then off you go," she said. She pushed and Denison felt himself begin to move. He moved quite slowly at first. He turned toward her, wobbling, and she said, "Don't worry. I'm right at your side."
He could feel the ground beneath his feet-and then he couldn't. The glider had been activated.
For a moment he felt as though he were standing still. There was no push of air against his body, no feel of anything sliding past his feet. But when he turned toward Selene again, he noticed that the lights and shadows to one side were moving backward at a slowly increasing speed.
"Keep your eyes on the Earth," Selene's voice said in his ear, "till you build up speed. The faster you go, the more stable you'll be. Keep your knees bent… You're doing very well, Ben."
"For an Immie," gasped Denison. "How does it feel?"
"Like flying," he said. The pattern of light and dark on either side was moving backward in a blur. He looked briefly to one side, then the other, trying to convert the sensation of a backward flight of the surroundings into one of a forward flight of his own. Then, as soon as he succeeded, he found he had to look forward hastily at the Earth to regain his sense of balance. "I suppose that's not a good comparison to use to you. You have no experience of flying on the Moon."
"Now I know, though. Flying must be like gliding-I know what that is."
She was keeping up with him easily.
Denison was going fast enough now so that he got the sensation of motion even when he looked ahead. The Moonscape ahead was opening before him and flowing past on either side. He said, "How fast do you get to go in a glide?"
"A good Moon-race," said Selene, "has been clocked at speeds in excess of a hundred miles an hour-on steeper slopes than this one, of course. You'll probably reach a top of thirty-five."
"It feels a lot faster than that somehow."
"Well, it isn't. We're leveling off now, Ben, and you haven't fallen. Now just hang on; the glider will die off and you'll feel friction. Don't do anything to help it. Just keep going."
Selene had barely completed her remarks when Denison felt the beginning of pressure under his boots. There was at once an overwhelming sensation of speed and he clenched his fists hard to keep from throwing his arms up in an almost reflex gesture against the collision that wasn't going to happen. He knew that if he threw up his arms, he would go over backward.
He narrowed his eyes, held his breath till he thought his lungs would explode, and then Selene said, "Perfect, Ben, perfect. I've never known an Immie to go through his first slide without a fall, so if you do fall, there'll be nothing wrong. No disgrace."
"I don't intend to fall," whispered Denison. He caught a large, ragged breath, and opened his eyes wide. The Earth was as serene as ever, as uncaring. He was moving more slowly now-more slowly-more slowly-
"Am I standing still now, Selene?" he asked. "I'm not sure."
"You're standing still. Now don't move. You've got to rest before we make the trip back to town… Damn it, I left it somewhere around here when we came up."
Denison watched her with disbelief. She had climbed up with him, had glided down with him. Yet he was half-dead with weariness and tension, and she was in the air with long kangaroo-leaps. She seemed a hundred yards away when she said, "Here it is!" and her voice was as loud in his ears as when she was next to him.
She was back in a moment, with a folded, paunchy sheet of plastic under her arm.
"Remember," she said, cheerily, "when you asked what it was on our way up and I said we'd be using it before we came down?" She unfolded it and spread it on the dusty surface of the Moon,