Corps of Linear Reckoning

The Corps of Linear Reckoning is a standing body of the Tower charged with the measurement, certification, and (since the disputed recension of Winter 114) the periodic re-measurement of corridors and stairwells. It is one of the three bodies that interpret survey data, alongside the Guild of Chain-Bearers and the Bureau of Linear Hermeneutics, and no finding of the Chain-Bearers is entered into the standing register until the Corps has ratified it. The Corps also governs linear feet of the kind that no other office will admit to managing: those of stairwells, spiral ramps, and inclined corridors. Level floors are the affair of the Bureau of Linear Feet. The division was meant to be clarifying.

Foundation and the question of precedence

The Corps was constituted by the Ninth Concordance, which established at the same sitting the Cartographic Corps, the Bureau of Apparent Duplication, and the office of the Clerk-Registrar of Linear Standards. Here the record becomes difficult. The Ninth Concordance, Annex 2, fixes the precedence of the three offices "in the order in which they are named," but the enrolling copy held by the Registrar Corps names the Corps of Linear Reckoning first, while the reading copy used in the scriptoria names it third. The discrepancy is traceable to a copyist who, by his own marginal note, "thought the order wanted improving." He was not disciplined, and the two copies remain in use.

In practice the Corps asserts seniority over the Bureau of Linear Feet at every joint sitting and does not press the point otherwise. The Bureau has never disputed it in writing.

Jurisdiction over the inclined

The Corps' distinctive competence is the inclined plane. A corridor is reckoned to be inclined, for the Corps' purposes, when a plumb line dropped at its threshold does not meet the far sill; the threshold of ineligibility is eleven parts in one thousand, a figure taken from an appendix to Ordinance Kappa-19 and retained after the rest of that appendix was superseded. This produces the well-known anomaly of the Gamma Corridor on the 208th landing, which measures as inclined when entered from the north and level when entered from the south. The Corps has certified both measurements. When pressed, the Corps cites the requirement in Kappa-19 that findings be "ratified in the direction from which the surveyor walked."

The Corps' jurisdiction overlaps that of the Bureau of Linear Feet in precisely the spaces where the overlap causes most trouble, and Ordinance 412.7 has never been harmonised with Kappa-19. The standard reconciliation, known informally as the Walking Rule, holds that the Corps measures a space one may walk through while ascending and the Bureau measures a space one may walk through while descending. On the spiral ramps of the lower levels, where ascent and descent are indistinguishable for stretches of more than a quarter-turn, surveyors are permitted to decide by lot. The lot is drawn in the presence of a witness from the Sub-basement Cataloguing Corps and is recorded as a determination of fact.

Procedure and the ratification of findings

The Corps does not measure. Measurement in the interior is the province of the Guild of Chain-Bearers, whose chains and tapes are maintained to a standard the Corps inspects but does not set. The Corps receives findings, examines the supporting tape-ends, and issues ratification. A finding is ratified, returned, or ratified with reservation. A reservation is entered in red and is binding on no one.

The affair of Clerk Amaranth

In the winter of 114 the Corps returned a Chain-Bearers finding on the Great Stair as "ratified with reservation: length exceeds the sum of its treads by the height of one tread, for which no charge is entered." The reservation was copied verbatim into the register on six successive occasions before anyone read it. The clerk responsible, Clerk Amaranth Voile, protested that she had written the phrase to flag the anomaly of the rotary landing and had not understood the clause to require repetition. The Corps found, by a majority, that the repetition was procedurally correct. Voile's request that the phrase be struck from the standing register was refused and is still on file in the Bureau of Linear Hermeneutics, where it is cited as a model of the unresolvable.

"A reservation is not a correction. The register is not improved by being shorter."

— Ordinance Kappa-19, Clause 8

Disputed questions

Two matters divide the Corps from its neighbours. The first concerns the Lens of Linear Scrutiny, an instrument of the School of Linear Dependency which the Corps is permitted to borrow but not to adjust. The School maintains that the Lens reveals dependency between adjacent lengths; the Corps maintains that what the Lens reveals is error in the tape, and that a tape which agrees with the Lens on one landing and disagrees on the next has been handled carelessly. The Lens has been out on loan since 121. Neither body has requested its return.

The second concerns linear time. Ordinance Kappa-19 designates linear time as the administrative substrate for all holdings not filed under a Cyclical Calendar, and the Corps has read this provision to extend its reckoning to duration as well as distance. The disagreement with The Committee for Linear Time vs. The Looped Hour is old and has been heard three times. The Committee's rulings are provisional and non-binding under Kappa-19 but carry significant persuasive weight, and the Corps has accordingly stopped scheduling its sittings by the hour and schedules them by the corridor instead. The 40th landing corridor is a little over four hundred feet. A sitting runs its length.

Recognition and insignia

The Corps' seal depicts a plumb line falling past a stair, with the bob resting on nothing. It has been redrawn twice; both earlier seals are retained by the Transcription Corps and are, by standing order, not to be corrected. Members wear the grey cord of measurers on the left shoulder only. Visitors to the ratification chamber are asked to leave their own tapes at the door, and the attendant will not hold them.