Spire 7's Penumbral Stair

Description

Spire 7's Penumbral Stair is the vertical access structure serving Spire 7 of the Third Spire complex, and is one of seven known constructions in the Tower to be catalogued under a shadow designation rather than a number. It rises from an unnamed landing below the Atrium of Lapsed Mandates to a terminus disputed in the record, and is used almost exclusively for the transport of Penumbral Artifacts between Floor 719-β and the Penumbral Atrium. The stair is not considered part of the Third Spire portal jurisdiction, a distinction maintained by the Office of Apertures at some inconvenience to itself.

The stair consists of 1,104 treads of grey stone, each worn to a depth of between 3 and 11 millimetres at the centre, and is notable for the fact that no two consecutive treads receive light at the same intensity. This property is intrinsic to the structure and is not a consequence of aperture placement, as was established during the Wenrick Survey of the winter of 884.

History

The earliest surviving mention of the stair appears in the Fourth Concordance, Annex 19, where it is referred to as "the stair that is not counted," a phrasing later struck through in the recension of 711 without replacement. Whether the stair existed before the annex or was retroactively named by it has never been settled, and the Office of Scriptoria Insertions has declined on four occasions to reopen the question, citing the shortage of vellum.

In 884 the stair was surveyed by a party of three cartographers from the Cartographers' Spire, who recorded its pitch as varying by 1.4 degrees over the span of a single flight. The variance was reported to the Office of Measures and subsequently corrected in the official tables to 0.0 degrees. The original measurement survives in the Wenrick Survey because Wenrick, contrary to instruction, kept a copy.

During the disputes of the Silent Stair, Spire 7's Penumbral Stair was claimed briefly by the Sultanate of the Silent Stair on the grounds that its shadow-designation rendered it unnumbered and therefore subject to silent governance. The claim was contested by the Central Administrative Spire and lapsed after eleven days, though the Sultanate has never formally withdrawn it. The stair now carries a small brass plate at its foot reading NUMBERED FOR PURPOSES OF TRANSIT ONLY, installed in 887 and twice removed.

Use in Penumbral Transit

The stair is the sole means of moving a Penumbral Artifact from the pre-processing facilities on Floor 719-β up to the Penumbral Atrium without passing through the Fifth Stair, which is prohibited for such purposes under the Eleventh Concordance, Clause 3. Artifacts are carried by two attendants, one ascending and one descending, who do not speak during the transit and do not meet on the stair. Should they meet, the artifact is returned to its shelf and the transit begins again the following day.

The alternating light of the treads is understood to assist in keeping a carried artifact at a stable penumbral gradient, though the Penumbral-Gradient Index is still read at both ends of the transit as a matter of form. A reader unfamiliar with the stair may find the pattern disorienting; visitors are advised to keep one hand on the rail and not to count the treads.

Related Stairs

The stair is frequently confused with The Quiet Stair, which serves a similar function in a different spire, and with the Stair of Unvoiced Echoes, which is not a stair in the structural sense but is nonetheless listed alongside it in the compendium of vertical passages. The Empiricists of the Calibrated Stair have twice petitioned for its inclusion in their calibration rounds; both petitions were declined on the grounds that the stair's pitch, being variable, cannot be calibrated to a single figure.

The nearby Spiral Stair of Spire 4, by contrast, is numbered and entirely unshadowed, and is often held up as the standard against which Spire 7's Penumbral Stair is found wanting. This comparison is considered unfair by the Office of Vertical Matters and has been discouraged in writing since 889.

Disputed Points

The Fourth Concordance and the Ninth Concordance disagree on whether the stair terminates above or below the interstitial level housing the Atrium of Lapsed Mandates. The Fourth places it above; the Ninth places it below and adds, without explanation, that "the shadow of a stair does not obligate the stair." Two attempts to reconcile the passages have produced three additional glosses and no resolution.

"The stair is where it is. The Concordances may be brought to it; it will not be brought to them."

— Wenrick, Survey of the Winter of 884, Appendix C

A second dispute concerns the number of treads. The Office of Vertical Matters records 1,104. The Wenrick Survey records 1,105. A third count, undertaken by an unnamed attendant in 891 and never repeated, recorded 1,103 and noted in the margin that "one of them is not a tread." The page was later filed under Floor 712 without comment.