Blackheath was reached by a carriage ride that was an exercise in patience pure and simple, a weighty, hushed journey through the city's dark, unchanging night. The fog, thick and yellow as old bile, dampened the city sounds until the horse's clip-clop on the cobblestones seemed impossibly far away, as if from some other room altogether. The driver, a burly shape shrouded in soot, addressed himself only to give directions, his words guttural and short. Elias monitored the Ravenwood journal, whose black cover was a chill, oily talisman against the insidious pressure of the Lingering Pall.
They pulled up at the iron gates of the observatory just after midnight. The building stood as a self-satisfied, isolated sentinel on a hill—a dome of oxidized copper atop a platform of gray stone. It seemed more like a human study facility in name only and far more like a gigantic, metallic cranium gazing blankly into the uncaring heavens. Elias experienced an immediate pressure on his mind, the certain sense that this was filled with a deep, horrifying moment of understanding.
The driver took his fare without speaking, his unnerving absence of expression melting at once into the clinging darkness. Elias drew out the Society's master key, a chunky, metallic thing that felt cold to the touch and represented his sanctioned intrusion into the lives of the dead. The lock turned with a soft, absolute click, and the air within the entrance hall had the scent of ozone and long, undisturbed dust.
The observatory was deeply still. The lower floor was home to the mounts of the telescopes, giant bony machines for cutting through time and space. But Elias wasn't interested in celestial physics; he was drawn to the ritual of erasure that had played itself out here. He ascended the narrow, chilled iron stair to the dome itself, his own footsteps ringing harshly.
Dr. Ravenwood's room was sealed and motionless. The police chalk marks had vanished, but the air retained the metallic tang of official despair and a faint, acrid residue of the bitumen. The room itself was a circle, a perfect, inevitable cylinder. The blackness was total, except for a shaft of spent moonlight that cut across the viewport of the dome—the one patch Ravenwood had left open to observation.
Elias moved up to the windows. The bitumen was not painted on; it had been slapped on in frantic, deliberate strokes, heavy enough to guarantee complete occlusion. It was a violent, desperate refusal of visibility, a man trying to blind the world to himself, or himself to the world.
Elias took care to scrape off a tiny, inconspicuous corner with his scalpel. The bitumen chipped off, exposing the thick glass underneath. He held his high-powered magnifying glass up against the glass. The glass, where it had been concealed, was artificially immaculate. But along the edges, where the bitumen had been slapped on in a hurry, Elias discovered the decisive detail.
Blended into the tarry mixture were tiny, near-microscopic, scales of silver nitrate.
Silver nitrate. photography.
Ravenwood had not merely been shielding the light; he had been trying to neutralize or bounce back the unique, unseen energy of the Pall. Bitumen kept visible light out; silver nitrate was the active chemical substance that trapped light in the darkroom, fixed an instant in place forever. It was a scientific, desperate struggle against shadow with the very stuff of memory holding. The astronomer must have speculated that the Pall was some sort of perversion of the photographic process, a negative print of the world being pressed into reality itself, and that he was attempting to create an antidote.
Elias walked around the round room, scanning the floor where the body of Ravenwood had lain. His eyes finally came to rest by the base of the central telescope, below a crumpled, oil-stained rag. He drew the rag aside.
There, stretched and twisted by some unseen force, was a tiny, oblong shape—the discarded metal can of a photographic plate. Beside it lay a solitary, half-burnt albumen print. It was a picture of a bright, sunny lawn—a sight utterly alien to the darkness of London. In the foreground stood Ravenwood, young, smiling, his arm around a woman with bright, warm eyes. A strong, perfect memory, preserved by light and chemistry.
But the picture was not just burned; it was corrupted to a profoundly unnerving extent. A part of the woman's face—from left eye to chin—wasn't scorched, but had been supplanted by the oily, sticky black color of the Pall. It was as if the darkness, sensing the ferocity of the memory, had stretched into the picture and forcibly devoured the light, the self, and the joy of the subject.
The flash memory that had invaded Elias's mind—the impossibly tall spire, the ancient brine, the smell of forgotten maths—was not arbitrary. It was the byproduct of the Pall, a psychic bleed from the shared memory it was recording or maybe projecting onto witnesses.
Elias gently took the photograph. The Pall had left its mark: a malignant, non-physical corruption of individual memory given form. Ravenwood's suicide, Elias understood, was the last, desperate attempt of a man to prevent the Pall from consuming more than just the light. He was protecting his own memories, and maybe, the whole city, from the insidious, psychic smear of the unseen things. He was attempting to un-see the truth.
Elias pocketed the journal and the partially consumed photograph within his jacket. He had the physical proof of the anomaly. The Gilded Cage was actively bleeding, and the beings sustaining it were employing the Pall to eliminate the witnesses. Elias Thorne now possessed the tainted remembrance of a man who witnessed too much, a man killed by the truth. His mission was evident, and it was the same mission that had driven his existence for eight years: comprehend the Lingering Pall before it devoured him and the tenuous threads of Amelia's recollection completely. The observatory's shadows, now occupied, pushed against his determination. He knew, with a chilling conviction, that the inquiry was no longer one of a murdered astronomer; it was survival of the personal history itself.