Præsidium

The Præsidium is the central tower of the Mynster, where the four great clock dials are mounted high on its walls. Those dials—made in different ages but driven by the same internal works—proclaim the time, day, month, lunar phase, year, and other cosmographical details read by the knowledgeable. Above, the roof supports the starhenge, which is mechanically coupled to the same clock‑works.

First Appearance and Context

Introduced during a description of the great clock and the central building, the Præsidium is identified as the Mynster’s core tower, the place most people mean when they speak of “the clock.” It is observed in operation during the daily rite when the main weight is wound and raised.

During Apert, observers look up to where the Præsidium’s pillars pierce the Mynster’s vault and see movement as auxiliary weights descend. On a decennial opening, the cube and the octahedron come into view, their descent actuating the Year Gate and the Decade Gate; the weights slow and halt just above the chancel floor to general cheers.

Structure and Features

• Plan and elevation: The tower stands on four pillars and is square in cross‑section for much of its height. Above the dials its corners are chamfered to an octagon, then to a sixteen‑sided form, and finally to a round upper stage beneath a slightly domed roof.
• Chancel pillars and main drive weight: Four fluted stone legs pierce the Mynster’s vault and ram down through the chancel. Between them hangs the main drive chain bearing a heavy nickel‑iron meteorite weight. It descends steadily as it powers the clock and is raised again during the winding rite.
• Auxiliary weights on rails: Four additional weights—a cube, octahedron, dodecahedron, and icosahedron—ride on metal rails fixed to the pillars. Each advances upward a little at each winding and descends only to open the Year, Decade, Century, and Millennium gates respectively.
• Reserve mechanism in the chronochasm: High within the tower, behind the dials in the “chronochasm,” a sealed stone chamber houses a spherical metal weight on a jack screw. This keeps the clock ticking during winding and can sustain a reduced mode if the daily rite is missed.
• Winding hub: At the center of the chancel floor, a squat round hub with four horizontal poles acts as a capstan. At the proper cue during Provener, four winders push the poles to overcome static friction and lift the main weight.
• Starhenge and clockworks: The roof carries the starhenge and various domes and turrets, mechanically coupled to the same works that power the dials and weights. Megaliths around its perimeter serve as compass points visible from below.
• Dials and belfries: Each dial sits above a screened belfry.
• Buttresses and outlying towers: Below the belfries, plunging buttresses tie the Præsidium into four surrounding towers. Arches and tracery web these elements together, defining the broad plan of the Mynster.
• Interior stair and access: A spiral stair runs within the tracery walls, reached via stairs in the corner towers. Portcullises in the four towers can be raised or lowered to control which math has access—typically one at a time during the hours of darkness—as set by the Master of the Keys.
• Courts of the Wardens: Immediately below the starhenge, the courts of the Wardens are cloister‑shaped, each with a square opening through which the Præsidium rises; walkways around the openings give clear sight‑lines down into the chancel and up toward the roof.
• Bell works: Bell‑ropes climb from the ringers’ gallery to a carillon; other shafts and chains lead down from the chronochasm where automatic mechanisms chime the hours.
• Roof apparatus couplings: Vertical shafts pass up through the roof to drive rooftop loads such as the telescopes’ polar drives and the noon synchronizer prism. The roof also bears smaller domes, a windowless laboratory for photomnemonic tablets, a heated chapel, and the central Pinnacle at the summit. A fixed all‑sky sensor known as “Clesthyra’s Eye” records the entire sky in a single view.

Relationships and Functions

• Architectural and mechanical hub: The Præsidium concentrates the structure and mechanics of the great clock, linking dials, gates, and the starhenge.
• Maintenance: The Ita are said to tend the chains, sprockets, gear‑trains, and subterranean works connected to the tower and its clock.
• Overlook and oversight: Above the vaulted ceilings stands the aerie of the Warden Fendant with a perimeter sentinels’ walkway. Beneath its braces are inward‑bending gargoyles associated with the Warden Regulant, whose shaded windows look inward over the Concent.
• Access and Discipline: At night, the corner‑tower portcullises are configured so that a single math has sole access to the stair and the starhenge; assignment is set by the Master of the Keys, a hierarch, and is signaled visibly from below.

Current Status

Active and intact; its dials and upper works operate in concert with the internal weights and the starhenge, and the winding hub is used in the daily rite to raise the main weight.