Grandfraa Mentaxenes pulled open the little door that penetrated our screen. He was very old, and we were pretty sure that doing this every day was the only thing that kept him alive. Each of us stepped into a tray of powdered rosin so that his feet could better grip the floor.

Then we filed out and, like grains of sugar dropped in a mug of tea, dissolved in a vast space. Something about the way the chancel was built made it seem a cistern storing all of the light that had ever fallen upon the concent.

Looking up from a standpoint just inside the screen, one saw the vaulted Mynster ceiling almost two hundred feet above, illuminated by light pouring in through stained-glass windows in the clerestory all around. So much light, shining down onto the bright inner surfaces of the eight screens, rendered them all opaque and made it seem as though the four of us had the whole Mynster to ourselves. The Thousanders who had clambered down their walled and covered stair to attend Provener were now seeing us through their screen, but they could not see Artisan Flec, with his yellow T-shirt and his speelycaptor, in the north nave. Likewise Flec could not see them. But both could view the aut of Provener, which would take place entirely within the chancel, and which would be indistinguishable from the same rite performed one, two, or three thousand years ago.

The Præsidium was supported by four fluted legs of stone that rammed down through the middle of the chancel and, I imagined, through the underlying vault where the Ita looked after the movements of their bits. Moving inward we passed by one of those pillars. These were not round in cross-section but stretched out diagonally, almost as if they were fins on an old-fashioned rocket-ship, though not nearly as slender as that implies. We thus came into the central well of the Mynster. Looking up from here, we could see twice as far up, all the way to the top of the Præsidium where the starhenge was. We took up our positions, marked by rosin-stained dimples.

A door opened in the Primate’s screen, and out came a man in robes more complicated than ours, and purple to indicate he was a hierarch. Apparently the Primate was busy today—also probably getting ready for Apert—and so he had sent one of his aides in his place. Other hierarchs filed out behind. Fraa Delrakhones, the Warden Fendant, sat in his chair to the left of the Primate’s, and Suur Trestanas, the Warden Regulant, sat to the right.

Fifteen green-robed fraas and suurs—three each of soprano, alto, tenor, baritone, and bass—trooped out from behind the screen of the Unarians. It was their turn to lead the singing and chanting, which probably meant we were in for a weak performance, even though they’d had almost a year to learn it.

The hierarch spoke the opening words of the aut and then threw the lever that engaged the Provener movement.

As the clock would tell you, if you knew how to read it, we were still in Ordinal time for another two days. That is, there was no particular festival or holiday going on, and so the liturgy did not follow any special theme. Instead it defaulted to a slow, spotty recapitulation of our history, reminding us how we’d come to know all that we knew. During the first half of the year we would cover all that had gone before the Reconstitution. From there we would work our way forward. Today’s liturgy was something to do with developments in finite group theorics that had taken place about thirteen hundred years ago and that had caused their originator, Saunt Bly, to be Thrown Back by his Warden Regulant and to live out the remainder of his days on top of a butte surrounded by slines who worshipped him as a god. He even inspired them to stop consuming blithe, whereupon they became surly, killed him, and ate his liver out of a misconception that this was where he did his thinking. If you live in a concent, consult the Chronicles for more concerning Saunt Bly. If you don’t, know that we have so many stories in this vein that one can attend Provener every day for one’s whole life and never hear one repeated.

The four pillars of the Præsidium I have mentioned. Right in the middle, on the central axis of the whole Mynster, hung a chain with a weight at its end. It reached so high in the column of space above us that its upper reaches dissolved into dust and dimness.

The weight was a blob of grey metal shot through with voids, as if it had been half eaten by worms: a nickel-iron meteorite four billion years old, made of the same stuff as the heart of Arbre. During the almost twenty-four hours since the last celebration of Provener, it had descended most of the way to the floor; we could almost reach up and touch it. It descended steadily most of the time, as it was responsible for driving the clock. At sunrise and sunset though, when it had to supply the power for opening and closing the Day Gate, it dropped rapidly enough to make casual spectators scurry out of its way.

There were four other weights on four other, independently moving chains. They were less conspicuous because they did not hang down in the middle, and they didn’t move much. They rode on metal rails fixed to the four Præsidium pillars. Each of these had a regular geometric shape: a cube, an octahedron, a dodecahedron, and an icosahedron, all wrought from black volcanic stone quarried from the Cliffs of Ecba and dragged on sledge trains over the North Pole. Each rose a little bit every time the clock was wound. The cube descended once a year to open the Year Gate and the octahedron every ten years to open the Decade Gate, so both of these were now quite close to the tops of their respective tracks. The dodecahedron and the icosahedron did the same for the century and millenium gates respectively. The former was about nine-tenths of the way to the top, the latter about seven-tenths. So just from looking, you could guess it was about 3689.

Much higher in the Præsidium, in the upper reaches of the chronochasm—the vast airy space behind the dials, where all of the clock-work came together—was a hermetically sealed stone chamber that contained a sixth weight: a sphere of grey metal that rode up and down on a jack screw. This kept the clock ticking while we were winding it. Other than that, it would only move if the meteorite was on the floor—that is, if we failed to celebrate the daily aut of Provener. When this happened, the clock would disengage most of its machinery to conserve energy and would go into hibernation, driven by the slow descent of the sphere, until such time as it was wound again. This had only ever occurred during the three Sacks and on a few other occasions when everyone in the concent had been so sick that they’d not been able to wind the clock. No one knew how long the clock could run in that mode, but it was thought to be on the order of a hundred years. We knew it had continued to run all through the time following the Third Sack when the Thousanders had holed up on their crag and the rest of the concent had been uninhabited for seven decades.

All of the chains ran up into the chronochasm where they hung from sprockets that turned on shafts, connected by gear-trains and escapements that it was the Ita’s business to clean and inspect. The main drive chain—the one that ran up the middle, and supported the meteorite—was connected to a long system of gear-trains and linkages that was artfully concealed in the pillars of the Præsidium as it made its way down into the vaulted cellar below our feet. The only part of this visible to non-Ita was a squat hub that rose up out of the center of the chancel floor, looking like a round altar. Four horizontal poles projected like spokes from this hub at about the height of a person’s shoulder. Each pole was about eight feet long. At the proper moment in the service, Jesry, Arsibalt, Lio, and I each went to the end of a pole and put his hands on it. At a certain beat in the Anathem, each of us threw himself behind his pole, like a sailor trying to weigh anchor by turning a capstan. But nothing moved except for my right foot, which broke loose from the floor and skidded back for a few inches before finding purchase. Our combined strength could not overcome the static friction of all the bearings and gears between us and the sprocket hundreds of feet above from which the chain and the weight depended. Once it became unstuck we would be strong enough to keep it going, but getting it unstuck required a mighty thrust (supposing we wanted to use brute force) or, if we chose to be clever, a tiny shake: a subtle vibration. Different praxics might solve this problem in different ways. At Saunt Edhar, we did it with our voices.