The Weeping Ashlar

Seven inches below the water table, river damp always tasted of iron shavings and bitter lye. That was the rule Norris Claver carried down thirty-two spiral steps into the dripping dark of the pier vault, along with an iron scraper, a brass plumb-bob on greasy twine, and a girl who had lost four mules three hours ago and still had not spoken.

Norris stopped on the lowest limestone landing, where the masonry met the rough-hewn basalt footing of the river spindle. The air down here had the thick, woolly weight of wet fleece. Water ran down the dressed ashlar blocks in dark ribbons, humming with the cataract's sixty-foot drop beyond the five-foot stone collar. But beneath the raw roar of the Varrow gorge ran another cadence: three slow, heavy thuds against the granite soles of his boots, spaced like a diver's resting pulse.

"Hold the lantern higher, Elspeth," Norris said, his voice bouncing dry and brisk off the curved vault. "Not toward the well. Toward the second course bed-joint. I cannot read an ashlar seam by the grace of your kneecaps."

Elspeth Murrough lifted the perforated tin horn. Her knuckles were yellow with dried river clay, her sleeves sodden to the elbow from the bridge wreckage above. She did not argue. The beam of candle glow cut through the steam, fixing on a horizontal seam between two four-ton granite stretchers.

Norris adjusted the hemp cord looped behind his ears to keep his wire spectacles from sliding down his nose. He took the brass bob from his leather kit and let the point hang half an inch above the silt-smeared floorflags.

The weighted brass cone did not drift. It shuddered.

"Ten parts slaked fat lime, five parts washed river sand, two parts ground furnace slag," Norris muttered, his thumb tracing the braided cord. "That was the mix Aldous of Varrow swore by when King Kenneth's masons laid this apron fifty winters before the plague. A man could set a siege engine on this bed and crack the iron axle before the mortar yielded a hairline."

The plumb-bob clicked against the granite block with a metallic rhythm: tap, pause, tap.

"Is the rock shifting?" Elspeth asked. Her voice was thin, raspy from river spray.

"The rock does not shift," Norris snapped, pulling his folding rule from his apron pocket. "Basalt does not take a holiday, girl. Timber warps. Hemp rots. Men panic and let go of winch handles. Stone obeys load and gravity until some butcher of a lime-burner uses under-fired chalk."

He knelt in the shallow pool gathering near the well curb, heedless of the brown water soaking through the knees of his moleskin trousers. He drew his tapered iron feeler blade from his belt. If the pier was shearing under the flood's torque, the failure would show as diagonal stress fractures across the face of the stretchers, running upward from the river-side quoin. That would be catastrophic, but it would be ordinary physics: water leverage cracking stone.

He ran the feeler blade across the granite face. The ashlar was smooth, dressed with a claw chisel a hundred years before his grandfather took an apprentice. There was no fracture.

What ran between the blocks was worse.

The lime mortar in the half-inch horizontal bed-joint was not spalling into dry white powder under hydraulic pressure. It was bulging outward like rising dough. Pale yellow foam, thick as tallow, beaded along the lower lip of the upper block. Drops fell into the bilge with a soft, fatty plink.

Norris leaned his face within three inches of the seam.

Steam touched his cheek. It was not the cold, stinging vapor of autumn rapids. It felt like the draft from a washhouse boiler.

"Hold the horn steady," he told her, his hand reaching for the scraper.

He pressed the point of his index finger against the swollen mortar bead. The paste gave way instantly, offering no more resistance than curdled butter. When he pulled his finger away, a gray smear clung to his skin. It left no alkaline sting on his callus. It felt lukewarm, slick with an unctuous residue.

Norris brought his fingertip to his nose.

No sulfur. No slaked lime burn. It smelled of sun-baked river reeds and crushed water parsley, the sweet, heavy odor of a lowland marsh in midsummer.

"Master Norris?" Elspeth whispered from behind the lantern. "What is leaking?"

Norris did not answer. He touched the tip of his tongue to the wet paste on his thumb.

A good lime mortar should have bitten his tongue like hot coal, chemical and astringent. Instead, the flavor that coated his mouth was sugary and flat, resembling broth boiled from marsh lilies and wild leeks. It tasted fever-warm, carrying the mineral thickness of deep river gravel that had never seen noon sun.

His stomach tightened. For two seconds, reason slipped its moorings: stone was not supposed to sweat like a woman in labor. He rubbed his tongue hard against the back of his teeth until the sweet grease was gone.

"The binder is leaching," Norris said, his voice flat as a leveled board. "A failure of calcination. The kiln masters at Oakhaven must have burned their limestone over wet beech wood instead of seasoned oak. A third-century Roman defect. Every novice knows an under-burned lime fails when hydraulic head reaches forty feet."

"Does under-burned lime taste sweet?" Elspeth asked. She was staring at his fingers with dark, wide eyes.

"Everything tastes sweet to a fool who does not know mineral chemistry," Norris retorted. He reached into his kit and drew out a small, flat-bottomed glass apothecary vial with a waxed cork stopper.

He needed proof. If he went back up to Level 2 with only an artisan's complaint, Gable would wave his war-bow and Garret would look at him with those heavy, mechanical eyes, demanding to know if the gatehouse would stand until morning. Winch-tenders understood broken teeth on an iron drum; they did not understand the quiet betrayal of lime aggregate.

Norris set the rim of the glass vial against the lower edge of the mortar joint. With his right hand, he drew the curved scraper along the seam.

The steel should have screeched against aggregate. It should have thrown sparks against river sand.

Instead, the scraper sank into the joint up to its shoulder without a sound. The degraded mortar slid off the granite in smooth, rubbery ribbons, dropping into the mouth of the vial like rendered fat. Norris tilted the glass, filling it to the neck with the yellow-gray pulp. He jammed the waxed cork into the mouth, pressed it home with his thumb, and slipped the sealed vial into his leather waistcoat pocket. The glass felt strangely warm against his ribs, like a freshly laid egg.

"There," Norris said, rising to his feet and wiping his scraper on the hem of his apron. "Empirical evidence. We report to Garret. We wedge oak shingles into the weeping courses to relieve bed pressure, and we prepare dry slaked paste to point the joints from within."

"Master Norris," Elspeth said. She had not lowered the lantern. Her left hand pointed toward the hole his scraper had opened.

"What now, girl? I have the sample. The diagnosis is binder decay."

"Look into the joint."

Norris stepped back to the ashlar wall, irritated by the interruption. He bent his head, peering into the two-inch cavity his blade had carved between the granite blocks.

Behind the outer rind of mortar, deep in the dark void where no sunlight or river silt had reached since the gatehouse was founded, the bedding was hollow. And growing out of that hollow, clinging to the wet granite interior with fibrous, hair-thin pale roots, was a cluster of glossy green water-weed. Its supple fronds curled out into the draft of the cellar, wet with the warm juice of the stone, waving toward the yellow candlelight like grasping fingers.