Sourcery

exploded.
    The ground peeled back like lemon rind. Gouts of steaming mud spattered the wizards as they dived for the cover of the trees. Only Coin, Spelter and Carding were left to watch the sparkling white building arise from the meadow, grass and dirt pouring off it. Other towers erupted from the ground behind them; buttresses grew through the air, linking tower with tower.
    Spelter whimpered when the soil flowed away from around his feet, and was replaced by flagstones flecked with silver. He lurched as the floor rose inexorably, carrying the three high above the treetops.
    The rooftops of the University went past and fell away below them. Ankh-Morpork spread out like a map, the river a trapped snake, the plains a misty blur. Spelter’s ears popped, but the climb went on, into the clouds.
    They emerged drenched and cold into blistering sunlight with the cloud cover spreading away in every direction. Other towers were rising around them, glinting painfully in the sharpness of the day.
    Carding knelt down awkwardly and felt the floor gingerly. He signalled to Spelter to do the same.
    Spelter touched a surface that was smoother than stone. It felt like ice would feel if ice was slightly warm, and looked like ivory. While it wasn’t exactly transparent, it gave the impression that it would like to be.
    He got the distinct feeling that, if he closed his eyes, he wouldn’t be able to feel it at all.
    He met Carding’s gaze.
    “Don’t look at, um, me,” he said. “I don’t know what it is either.”
    They looked up at Coin, who said: “It’s magic.”
    “Yes, lord, but what is it made of?” said Carding.
    “It is made of magic. Raw magic. Solidified. Curdled. Renewed from second to second. Could you imagine a better substance to build the new home of sourcery?”
    The staff flared for a moment, melting the clouds. The Discworld appeared below them, and from up here you could see that it was indeed a disc, pinned to the sky by the central mountain of Cori Celesti, where the gods lived. There was the Circle Sea, so close that it might even be possible to dive into it from here; there was the vast continent of Klatch, squashed by perspective. The Rimfall around the edge of the world was a sparkling curve.
    “It’s too big,” said Spelter under his breath. The world he had lived in hadn’t stretched much further than the gates of the University, and he’d preferred it that way. A man could be comfortable in a world that size. He certainly couldn’t be comfortable about being half a mile in the air standing on something that wasn’t, in some fundamental way, there.
    The thought shocked him. He was a wizard, and he was worrying about magic.
    He sidled cautiously back toward Carding, who said: “It isn’t exactly what I expected.”
    “Um?”
    “It looks a lot smaller up here, doesn’t it.”
    “Well, I don’t know. Listen, I must tell you—”
    “Look at the Ramtops, now. You could almost reach out and touch them.”
    They stared out across two hundred leagues toward the towering mountain range, glittering and white and cold. It was said that if you travelled hubwards through the secret valleys of the Ramtops, you would find, in the frozen lands under Cori Celesti itself, the secret realm of the Ice Giants, imprisoned after their last great battle with the gods. In those days the mountains had been mere islands in a great sea of ice, and ice lived on them still.
    Coin smiled his golden smile.
    “What did you say, Carding?” he said.
    “It’s the clear air, lord. And they look so close and small. I only said I could almost touch them—”
    Coin waved him into silence. He extended one thin arm, rolling back his sleeve in the traditional sign that magic was about to be performed without trickery. He reached out, and then turned back with his fingers closed around what was, without any shadow of a doubt, a handful of snow.
    The two wizards observed it in stunned silence as it melted and dripped onto the floor.
    Coin laughed.
    “You find it so hard to believe?” he said. “Shall I pick pearls from rim-most Krull, or sand from the Great Nef? Could your old wizardry do half as much?”
    It seemed to Spelter that his voice took on a metallic edge. He stared intently at their faces.
    Finally Carding sighed and said rather quietly, “No. All my life I have sought magic, and all I found was colored lights and little tricks and old, dry books. Wizardry has done nothing for the world.”
    “And if I