Down in the underground wash-out cave beneath Pier Four, the scene was an inferno of steam, torchlight, and desperate human toil.
The timber cofferdam had been erected forty paces upstream, caulked with hot pine pitch and oakum, diverting the roaring sewer current into a heavy wooden bypass water chute that carried the waste away. The water in the cave had dropped to three feet. That left a vast, glistening crater of gray slurry beneath the hanging granite footing pad.
Four heavy naval force-pumps stood on timber staging platforms. Their brass cylinders shone in the red glare of twenty pitch torches. Relays of four men each threw their full body weight onto the ten-foot pump handspikes, pumping with a rhythmic, clockwork grunt: HEAVE-DOWN! HEAVE-DOWN!
Through heavy four-inch heavy leather hoses, thick gray volcanic cement grout was forced into the depths of the cave under forty-two pounds of pressure of crushing pressure.
The grout was hot. It steamed as the burning lime powder reacted with the fiery ash. It stretched into every crack, crevice, and void beneath the suspended stone blocks. The slurry pushed the leftover water toward the drainage sump. It replaced spongy mud with dense, heavy stone mass.
Suddenly, a sharp, terrifying crack echoed from the center of the void.
