By the spring of 1429 the red column in Tommaso’s ledger had grown so thin that the wardens noticed it before they noticed the dome.
He had kept the book of the works for nine years, since the season the goldsmith won the commission, and his right thumb carried the proof. The red ink of the safety column had worked so deep into the whorls that no pumice could lift it, though lately it had faded toward the pink of a healing scrape. Everything that protected the men or the building went in red: scaffold poles, railings, the planking of the walkways, the wages of the boy who checked the ox hoist’s harness each dawn. Everything that raised the dome went in black. Where a thing did both, the wardens’ rule was plain, read into the minutes in 1420 and never revisited. It belonged to the dome.
The senior warden turned the pages with one finger, the fur at his collar stirring with each breath.
“Nine hundred lire in red the year you closed the drum,” he said. “Four hundred the year after. This year, seventy.” He looked up. “The dome stands higher than any vault in Christendom, and the Guild spends less keeping men from falling off it than it spends on candles.”
“Every nail is entered, sir.”
“Your nails are in order. The goldsmith is another matter.” He closed the book over Tommaso’s hand. “He swore he could raise it without a centering, and we allowed it because all the timber in Tuscany would not frame a span that wide. Now I see where he finds his savings. He finds them in the safety of the men.”
Tommaso said nothing. The ledger was correct. That was what troubled him.
He had not climbed since the second ring. The stairs ran between the dome’s two shells, narrow enough that brick brushed both his shoulders, and the air grew warmer and drier with each turn, thick with lime and sweat. Twice he flattened himself against the wall for boys hauling mortar. At the top, a wine seller had set up his casks on the working platform, because the goldsmith would not let the masons lose half a day climbing down to eat.
Above the platform the dome curved inward over empty air. Tommaso gripped the railing, an item he remembered entering at eleven soldi, and made himself look.
The masons were laying a new course. Every few bricks they set one on end among the flat ones, and the upright bricks climbed from course to course in a slanting line, like the spine of a fish. A mason whitened with lime to the elbow caught him staring.
“Clerk. Come to count us?”
“The standing ones. What are they?”
The mason rapped one with his trowel. “Every ring wants to fall inward. This one holds the ring below it until the mortar takes, and the next one holds this one. She carries herself while we build her.” He spat lime from his lip and bent to the next brick.
Tommaso followed the spiral of upright bricks as it wound across all eight faces of the dome, and understood that he had watched the red column empty for nine years without seeing where it went. A centering would have held the vault from beneath. The goldsmith’s bricks held it from within.
Every one of them sat in black.
He brought the petition to the wardens the following Thursday, having drafted it three times. It asked that the upright bricks, and the labor of setting them, be carried in red, since they alone kept the dome from coming down on the men below.
The senior warden read it twice. “Do these bricks raise the dome?”
“They are the dome, sir.”
“Then they serve both purposes.” He drew the minute of 1420 from his sleeve; he had come prepared. “That rule exists so no clerk can dress the building up as charity. I will not bend it for the first clerk who asks.”
“Then the book will say the works are unsafe.”
“The book will say what the Guild spends on safety.” The warden rose, and the fur at his collar settled. “So the Guild will spend. We will raise a centering beneath it. Oak from the Casentino, as far as the forests will give it, and poplar after that.”
“It holds itself, sir. A centering would carry nothing.”
“It will carry the Guild’s good name.”
The order went out that afternoon. By autumn the carpenters had raised a forest inside the drum, ribs and struts reaching toward a vault they never touched, while the masons worked on above them, setting their standing bricks as before.
At the close of the quarter Tommaso entered the timber: eleven thousand lire, the largest safety expenditure in the history of the works. He wrote it in red, and his thumb came away stained.