It took exactly one minute for Sturm and Kitiara to demolish the Arch Doorway Widener, mostly for the same reasons as the Obelisk Escape Auger: lack of quality materi als. There was just no wood or metal to be had, except what the Cloudmaster and its crew had brought with them.

"It seems hopeless," said the dragon with a profound sigh.

"Never!" vowed Wingover. He pushed the bandages up from his face so that everyone could see his eyes. They had turned completely black. Wingover shielded them futilely with his hands.

"You see what has happened to me," he said, "I no longer can shut out anything. I have to sleep face down to the ground, where I count strata all the way down to the moon's core." He pointed with a thumb at Cutwood, next to him.

"My good colleague hears every grain of sand rubbing against another. Roperig's hands are almost sealed together, aren't they, Roperig? Rainspot's clothes are beginning to rot from the constant damp. All the rest of us have problems, too, but we won't leave until we solve this problem."

Sturm heard these words carefully. He said, "As long as we are discussing our gifts, let me show you this." He tore the cloth bandage from his leg. Where two nights and a day before there had been an ugly, gaping wound, there was now only smooth, unscarred skin.

"The same magic that makes trees walk and fight has healed my wound. I did not ask for it to be done, but it has convinced me of one thing. This is no place for mortals. I'll lend my aid, dragon, for that reason alone. The longer we remain on Lunitari, the more the magic will affect us. Since my companions have resolved to help you, my resistance only impedes their progress."

"Welcome to the struggle," said Cupelix.

"Wingover," Kitiara said, "if you can see into the ground we stand on, can you see any deposits of iron or copper?

Anything we can use?"

"Alas, lady, nothing. This entire moon seems made of sand, granite, and more sand."

"Sand," said Sighter, musing. He hopped down from the bench and strolled to the far wall and back. He traced a stubby finger along the lead seams where two marble cours es lay on top of each other. "Sand!" he shouted. "Sand, sand, sand!"

"Look out," said Rainspot. "He's slipped his gears."

Sighter took a deep breath and strode to Stutts with grave dignity. "Sand," he said, "is the one thing this world provides in abundance, yes?"

"Uh, yes," said Stutts.

Sighter snapped his spyglass open and laid it across his colleague's palm. "What are lenses made of?"

"Glass," Roperig said promptly.

Sighter whirled, pointing to the adhesive gnome. "And what do the Lunitarians make their weapons out of?"

"Glass," said Sturm and Kitiara together.

"Yes! And what is glass made of?" Sighter cried.

No one said a word. Finally, Fitter said, "Sand, but -"

"Sand, glass, lenses! Don't you see? We can cast a giant lens, and with that concentrate the rays of the sun into a burning beam. The focal point of the rays will be far hotter than the melting point of lead, so -"

"The wall will come tumbling down," said Cupelix. "Do you think you can do it!"

"Nothing is for certain," Sighter said with ungnomish cau tion. "We'll need a continuous source of heat for the melting of the sand."

"What about the heat source we found in the caverns?" said Sturm. "Would that be hot enough for you?"

"Hmm, magma is more than hot enough to melt sand," said Flash.

"The Micones can gather any amount of sand you'll need," said Cupelix. "Shall I get them started?"

"We'd better push the Cloudmaster outside," Stutts said.

"We'll need the floor space in here to work."

Cupelix summoned two ants, and the gnomes harnessed them to the bow of the flying ship. The Micones pulled the creaking craft through the doorway and out to the smoothed soil. The gnomes carried the detached wings and laid them in the shadow of the hull. Cupelix fell into a lengthy telepathic commune with his minions, and soon the

Micones were mustered in the valley. They surrounded the obelisk on all sides, an army of mute, clicking creatures, intent on a voice no one heard but them. Without as much as a nod, the three score giant ants turned their backs to the tower and began to plow the soil with their heads. Furrows of dull red sand turned up to the starry sky, and other

Micones pushed the sand into convenient mounds.

Sighter showed off his hasty design for a burning lens, twenty-two feet in diameter and five feet, seven inches thick in the center.

"Do you think it will work?" Kitiara said.

"If the lens can be cast in one piece, the polishing shouldn't take long. There's plenty of sand, after all," said

Sighter. He rolled up his parchment drawing and tucked it under his arm. Outside, the Micones slaved on, the ground trembling against the force of their unyielding heads.

Chapter 26

The Lens

To refine the sanb awd eliminate any impurities, the gnomes resorted to washing it. Poor Rainspot was hauled up to the lowest of Cupelix's ledges and instructed to make it rain for several hours. The floor of the obelisk grew quite grimy with wet sand and sodden vegetable muck. The dragon descended from his sanctum with the news that clouds were forming up there, too. A gentle rain was falling

450 feet above Rainspot. Midget streaks of lightning flick ered through the hollow shaft, glancing off the marble like minnows in a racing brook. Far from being annoyed, Cupe lix was delighted with all this. He had read of the mysterious thing called 'weather,' but had never experienced it.

"It doesn't naturally occur indoors," Sturm said sourly. He was wet to the skin, as the gnomes had appropriated his oil cloth slicker to make buckets for the clean sand.

Micones were fitted with pairs of big buckets, which were draped like saddlebags on each side of their globular thoraxes. They scuttled down to the cavern with their loads, where Sighter, Birdcall, and Flash were preparing the vat in which the sand would be melted. This, like the mold in which the lens would be cast, was simply and roughly made from mud. The disintegrated plant fluff that coated the entire red moon, mixed with dry dirt, made an admirable clay. The gnomes in the cavern slapped together a wide tub of mud, reinforced with just a few laths 'borrowed' from the

Cloudmaster. At about dawn, the vat was ready. With a

Micone as a draft beast, the gnomes shifted the vat into place over one of the volcanic vents. Then they sat back and waited for the clay to harden.

Flash's head popped up through one of the holes in the floor. "We're ready for the sand!" he cried.

Roperig moved closer to the hole and said, "What's hold ing you up?"

"Nothing," said the mud-caked gnome. "I said, we're ready for the sand."

"He means, what's holding you up in the hole?" said

Sturm.

"Oh! I'm standing on a Micone." The giant ant was cling ing upside down under the opening, and Flash was standing on its belly.

The whole crew, save Kitiara and Rainspot, descended to the great cavern. There the train of Micones saddled with hoppers of sand stood in a line, like a cavalry troop on parade. Each time Birdcall poked his head through the toothed passage in the rock and whistled, an ant detached and followed him.

Farther in, past the Micones' birthing chamber, the gnomes labored over the glass vat. Sturm watched as they emptied bucket after bucket into the baked mud bowl, spreading the sand evenly across the bottom and sprinkling in various unnamed powders they'd brought down from the flying ship. The heat in the chamber was terrific. On Cupe lix's orders, the Micones had broken open one of the magma flues, allowing more of the rock to well out of the ground.