The yellow canary died without a sound.
At the entrance of the level crawlway, forty feet behind them, the wicker cage had been hooked to an iron bracket three feet above the gravel floor.
Tomas looked over his shoulder as the sickening sulfur draft washed through the chamber. The yellow bird didn’t flutter its wings. It didn’t chirp. It simply wobbled on its birch dowel, its black eyes glazing over into dull gray film, and dropped like a lead plum-bob to the floor of the cage, its small claws curled into tight, rigid balls.
“Gas!” Sile shouted, his military training taking command before his lungs could seize. “Hydrogen sulfide surge! Out! Out of the hole!”
The gas hit Tomas’s throat like a handful of crushed burning lime powder.
His windpipe snapped shut in a violent, reflex laryngeal burst. The human body’s primal defense against breathing air that carries five hundred parts per million of sewer gas. A single full breath of air at that concentration paralyzes the smell nerve in two seconds, causes loss of mind in ten, and stops the heart within four minutes.
Tomas dropped the knife into the gravel, snatched his animal fat lamp by its wire bail, and shoved Sile Rook forward into the crawlway.
