Bellis knew the myths.

"There is one passage…," Doul mused (and Bellis realized with consternation how his wonderful voice was lulling her). " ‘The Verses of the Day.’ Perhaps you know them? ‘Redoubtable, tail flicking, swimming over a plain of worlds, past orbs, lights in the night’s blindness.’

"That describes the Ghostheads’ journey from… their place to Bas-Lag. In the belly of a metal fish swimming through a dark sea of stars. But what’s most interesting is the description of their home, where they came from. It has been confused with hell."

Uther Doul sat on his crib, and did not speak for some time.

Is this why I’m here?thought Bellis suddenly. Is this what he wants to tell me? He was like a boy, wanting her there but quite uncertain what to do.

"It describes the morning coming with ‘ferrous cataracts and a wall of fire,’ " he said eventually. "The entire eastern sky was ablaze with light and heat enough to blind anyone looking up even from the bottom of a sea, to ignite the air, burn the mountains, liquefy metal. Far, far hotter than the heart of any foundry. Morning broke, and the world burned.

"Within minutes the wall of heat had risen and curved above them, directly overhead, blotting out the sky and burning every atom of gas in the air. And then, as the minutes went on, the fire shrank, until its edges became visible, and it was a disc. And the heat began to ebb away a little, though the oceans were still molten iron.

"The fire in the sky receded, moving west, as the day passed. By midmorning, the disc had shrunk further, and it was the sun, nearly at the far horizon. By noon it was much smaller, and the land was very cold.

"The sun shrank and traveled west in a long, drawn-out dusk, and the Ghosthead homeworld became icier than the Rime Ocean. By nightfall, the sky was already dark, and the sun was no more than a moving star.

"And it was cold -colder than anything we could imagine. The world was enveloped in layers of ice and frost-the very gases, the very aether piled up in bergs and walls, chilled more solid than stone."

He gave Bellis a faint smile.

"That was the Ghosthead homeland. Imagine what kind of creatures might live, might survive in such a place; how hungry they might be for rest. That’s why they left."

She said nothing.

"Do you know what I mean," Doul said, "by the belief in the Broken Country?"

Bellis furrowed her brow, then suddenly nodded. "In New Crobuzon we call it…" She thought for the translation. "The Fractured Land Hypothesis. I once had a friend who was a scientist. He was always talking about things like this."

"The Broken Country, across an impossible sea," said Doul. "I spent a long time, in youth, studying myths and cosmogony. Fractured Land, Ghosthead Country, the Verses of the Day.