Cartogram of Perpetual Deferral

The Cartogram of Perpetual Deferral is a bound series of sixty-one map plates depicting the compartments, aisles and stairwells subject to Passive Deferral, rendered according to the principle that no depicted feature may be shown in the position it currently occupies. Prepared under the direction of the Office for the Management of Perpetual Affairs between 3 Verge and 29 Verge, the Cartogram is the only sanctioned cartographic instrument for navigating deferred holdings. Its plates are revised continuously and have never all been current at the same time.

The Cartogram does not show where anything is. It shows where everything has agreed to be considered from, pending confirmation.

Composition and plate sequence

The work is issued in nine fascicles of six plates, with a sixty-first plate — the Index Plate — bound at the front and itself numbered last. Fascicles are not issued in order. The Office for the Management of Perpetual Affairs has ruled twice that the correct sequence is discoverable and once that it is not, and clerks are directed to consult whichever ruling was in force on the date of their commission.

Each plate carries a Deferral Certificate in its lower margin, countersigned by the plate's draughtsman and by a second clerk who has not seen the plate. The certificate states the date from which the plate's contents may be relied upon, expressed as an interval rather than a date. The shortest interval yet granted is four days, on Plate 38 (Shelf Runs, Western Compartments); the longest is the interval on Plate 7, which has not yet begun.

Cartographic method

The Cartogram follows the displacement rules set out in Annex 12 of the Manual of Perpetual Deferral, which requires that every mapped feature be offset from its location by a distance proportional to the length of time its file has been pending. Aisle heads pending fewer than three years appear nearly in place. A compartment pending nineteen years — the interval recorded for the Rotunda of Unfiled Returns — appears on Plate 22 as a mark in the outer margin, adjacent to the plate number.

Stairwells are shown only as descents or ascents, never both, and the direction is chosen by the draughtsman. Readers are instructed not to infer floor height from the space between stair marks.

"A plate is not a picture of the Tower. A plate is the Tower's intention to be pictured, entered on the register and awaiting the surveyor's convenience."

— Scroll of Perpetual Deferral, Annex β-7, §4

Dispute over Plate 7

The most sustained scholarly disagreement concerning the Cartogram is the status of Plate 7, the so-called Winter Plate, which depicts the closed compartments of Administrative Floor 44 and has never been issued in a form any two clerks have agreed upon.

The dispute originates in the winter of the third revision, when the draughtsman Emeric Vaunt, working from the survey returns of a single night, drew the Floor 44 cross-referencing galleries thirteen score feet to the left of their certified position. The error was not detected for eleven years, because the plate had been filed correctly. On its rediscovery, the Registry of Perpetual Debates entered the matter as Debate 4,116 and it has remained open since.

One body of opinion, citing Third Concordance §9, holds that a plate filed correctly is a plate correctly drawn, and that the galleries are therefore wherever Plate 7 says. The opposing body, citing the Ordinance of the Unsurveyed Margin, holds that no plate may displace a compartment under active audit, and that Plate 7 is void from the night of its survey. The Office has declined to resolve the question, noting in its minutes that both positions were reached in good order and that the galleries in question have since been converted to storage.

Practical use

Porters and shelf-auditors carry the Cartogram in three fascicles, selected by the desk clerk on the morning of the shift. Where the Cartogram and the aisle's own painted signage disagree, the signage governs; where the signage has been painted over, the Cartogram governs until the paint is dry. The prohibition on carrying all nine fascicles at once was introduced after the Petition of the Nine Fascicles and remains in force on all floors except the seventh, where the fascicles are kept in any case.

The Index Plate may not be removed from its binding. It is consulted by lifting the fascicle.

Relationship to other instruments

The Cartogram is a procedural companion to the Manual of Perpetual Deferral, which governs all matters of closure, filing and shelf-audit for Perpetual Aisles and which states at Clause 44(a) that no deferred aisle may be mapped except by instrument of the Office. It is subordinate to the Scroll of Perpetual Deferral in matters of theory and to the Treatise of Perpetual Autumn in matters of seasonal closure, and it is subordinate to nothing in matters of scale, having fixed the standard deferred inch at 1/61 of a compartment width since the first fascicle.

Copies held outside the Office are uncertified and are marked on the spine with a single horizontal rule. The Cartogram's readers are asked not to correct these copies in ink.