Office of Vertical Coincidence

The Office of Vertical Coincidence is a standing bureau of the Tower charged with the measurement, certification, and archival reconciliation of coincidences occurring along the vertical axis — that is, correspondences between floors that share neither a name, a number-series, nor a stairwell. It is among the oldest continuing offices, though its founding date is disputed and its founding document is missing. The Office maintains the Register of Certified Planar Surfaces, oversees the calibration performed by the Clerks of Coincidence, and certifies Official Planar Surfaces under protocols set out in the Seventh Concordance. It is not to be confused with the Office of Onomastic Coincidence, with which it has been in intermittent dispute since the Onomastic Impasse.

Origin and the lost founding instrument

The Office traces its authority to an instrument it calls the Vertical Warrant, which no Librarian has produced in living memory. The standard citation is to the Warrant's Article 3, which is quoted — always in the same words, always without a facsimile — in every recension of the Office's own handbooks: "What is above corresponds, and what corresponds is owed an account." The Office of Catalogic Logistics holds that the Warrant was absorbed into the Fourth Concordance and no longer stands alone; the Office disputes this and continues to cite the Warrant directly, a practice tolerated by the Librarians on the grounds that no one has established that it is wrong.

Physically, the Office occupies Floor 2,318, which its staff maintain is "vertical in intent" despite lying three floors beneath the Clerks' calibration annex. Signs in the corridor direct visitors to the Office by way of the east spiral, and a notice at the landing instructs that hats are to be removed before the readings begin.

Function and method

A vertical coincidence is logged when two floors record the same event without any channel of transmission between them. The Office does not ask what caused the event; it asks only whether the two floors describe it identically, and if not, which record is to be amended. In practice the office produces a coincidence file for each pairing, assigns it a certification state — Provisional, Recurrent, or Saturated — and passes the certified file to the Curators of Coincidence for authentication and containment. The Curators are obliged to reconcile their findings with the Office's map, and several have declined to do so in writing, which the Office treats as an absence of findings rather than a refusal.

Calibration of a floor's planar status is performed by the Clerks of Coincidence, who attend with plumb-lines, a spirit level of their own manufacture, and a brass rule graduated to a quarter-inch. The Office's inspecting officer signs the clerk's calibration sheet on the spot. Sheets signed after the calibration in question are not accepted; sheets signed before it are accepted, provided the clerk can be found to confirm them.

The Seventh Concordance and the question of surfaces

Certification of Official Planar Surfaces is governed by the Seventh Concordance, known throughout the Office as the Surface Concordance, though that title appears nowhere in its text. Annex 2 specifies that a surface may be certified planar if its deviations fall within "the ten-thousandth part of the rule, or such other quantity as the Office shall from time to time find convenient." The final clause is contested. Office of Vertical Acoustics reading of the clause is that "convenient" means convenient to the Surface, not to the Office; the Office has never answered this reading directly and has certified four floors under the clause without annotation.

"A deviation certified is a deviation owed; a deviation forgiven is a coincidence unrecorded, and the record will not forgive it."

— Seventh Concordance, Annex 2, marginal gloss (attributed to an unnamed Librarian)

Relationship with Correlative Cartography

Because the Office maps coincidences across floors rather than in plan, it maintains a standing liaison with Correlative Cartography to reconcile vertical data against the flat sheets. The liaison is conducted by exchange of overlay tracings, each of which must carry the Office seal and the cartographer's initials. In the winter of the year recorded as Year of the Third Recension, the overlays returned from Cartography were found to have been rotated ninety degrees, a fault traced to a shared drawing table. Seventeen floor-to-floor correspondences were reconciled in the wrong direction before the error was caught; the Office's correction, issued as Circular 11/, is still quoted by the Curators as a model of restraint, having retracted the correspondences without withdrawing their certification.

The Idle Week and the Clerks' Grievance

In Year of the Long Recess the Office's Examiner of Plumb, Alder Voss, recorded a fortnight in which every calibration returned the same deviation — three-eighths of an inch, in the same direction — across forty-two unrelated floors. Voss declined to certify the readings and entered the fortnight in the register as the Idle Week, on the reasoning that a coincidence occurring on every floor is not vertical but universal, and therefore outside the Office's writ. The Clerks of Coincidence, whose scale had been repaired in the interim, maintained that the fault lay in their instrument and not in the floors, and demanded that the readings be certified so that their calibration could be corrected. The demand is still pending before the Commissioner for Harmonic Integrity, who has heard oral argument four times and has not issued a ruling.

Voss's grievance, filed the same year, concerns the office's supply of sealing wax. The Office seal requires a wax harder than the general issue, and Voss's request for an increased allowance was refused on the grounds that Examiners of Plumb are not a sealing grade. He further complained that the corridor notice requiring the removal of hats applies to him as he passes it twice daily on the way to the east spiral, and that the notice has never been confirmed by any Concordance. Both complaints remain open.

See also

• Clerks of Coincidence
• Curators of Coincidence
• Office of Onomastic Coincidence
• Correlative Cartography
• Official Planar Surfaces