The canal cut through thirty feet of solid ice-slow ice like a hot wire drawn through beeswax.
It was Entry hall 798, a vast, low-vaulted hall four leagues north of the Great High window. Here, the lead heat drain tube they had followed along the floor flags swelled into an open aqueduct of cast iron eight paces wide, through which flowed a dense, steaming current of deep amber salt water.
The liquid was so heavy with dissolved stone salts that its surface possessed the sluggish, thick, sticky tension of hot oil. Where it contacted the upright ice walls of the cutting, it didn’t cause a violent collapse. Rather, it kept an exact, polished balance, melting only a fraction of an inch each day while the intense surrounding cold froze the runoff into crystal-clear fluting along the iron curbs.
A dense, pale vapor hovered two arm-lengths above the dark water, smelling of sulfur, ancient wood-ash, and the bitter stone bite of copper burning acid.
Qiao Ming stood barefoot upon the frost-slick margin of the iron curb. The contrast between the surfaces was startling: the hard black rock pavers beneath his right heel were thirty degrees below freezing. At the same time, his left toes dipped within an inch of the hot iron lip, bathed in a humid, rotten-egg warmth that made his chapped skin throb with prickling blood.
