The Porphyry Bridge of Entry hall 138 was the tuning fork of the western foundations.
The bridge was a massive single-span arch eighty arm-lengths long and ten arm-lengths wide, carved from blood-red stone that had been quarried from the deep-sea vents during the First Epoch. It crossed the Great Siphon Chute—a roaring underground canyon forty yards wide through which the entire flood-tide of Sector 130 was channeled toward the lower sound turbines.
The water below was violent. Six arm-lengths of foaming, white salt water roaring through the deep gap at twelve knots, throwing up sheets of cold, salty mist that coated the red stone in an unending glaze of glistening moisture.
Yet the bridge did not vibrate with the chaotic rough churning of the torrent.
Along the red stone railings on either side of the roadway, forty-eight hollow phonolite pillars were integrated into the stonework. Each pillar was drilled with sixteen sound sky-slits that captured the sound of the roaring water below and translated its high-pressure fury into a single, pure musical chord:
One hundred and forty-four hertz.
Qiao Ming stood at the center of the span, leaning against the red stone railing, his oilskin coat beaded with cold mist. He held his wooden ruler against the red stone low roof wall, feeling the intense, hum-like shaking running through the red stone into his forearms.
