Third Catalogue

The Third Catalogue is the third of the four recensions of the Central Catalogue and the recension presently in force on all floors reached by the Aperture Stair between Floors 214 and 1,090. It is not a single volume but a standing body of entries, annexes, schedules and corrections maintained continuously since its opening on the 1st of Sigma in the Year 101. Its scope is defined by the Third Concordance's recognition of Annex Q as a Primary Catalogue Annex, an instrument without which, the Librarians hold, the Third Catalogue would have no lawful edge and would simply continue.

The Third Catalogue is distinguished from its predecessors less by content than by its doctrine of authenticity. Where the Second Catalogue catalogued what it could verify and the First catalogued what it was told, the Third catalogues what can be shown to have been catalogued. This reflexivity is the source of both its authority and most of its difficulties.

Compilation and opening

Compilation began in the Year 99 under a commission of nine Librarians answerable to the Proctorate. The first folio was sealed on the 1st of Sigma, Year 101, and the recension was declared standing on the 14th. The opening was contested: the Survey of Aperture Holdings objected that Floor 872 had not yet been cleared of Second Catalogue instruments, and a rider was entered permitting the two recensions to run concurrently on that floor for a period not exceeding forty years. The rider expires in Year 181. No one has asked what happens then.

The Catalogue's present head is Librarian-Prime Anselm the Damp, elevated on the 7th of Sigma in the year 109 following the retirement of Librarian-Prime Vessel, whose own recension notes are held closed under the Office of the Receiver of Irregularities.

The Annex on Material Authenticity and Documentary Humidity

The Catalogue's most cited instrument is its Annex on Material Authenticity, which formally defines Documentary Humidity — the measurable moisture content of a folio at the moment of its accession — as a property bearing on the evidential weight of the entry it carries. The definition was drafted in response to the Dispute of the Damp Draft, in which two scriptoria produced irreconcilable copies of a single ordinance and neither could be preferred on textual grounds.

The Annex establishes five humidity bands, of which only three are in ordinary use. Entries accessioned in the fourth band are held to be "of doubtful dryness" and are catalogued in a lighter ink. The standard was extended in Year 119, when the regulated humidity of the Damp Stairwell was fixed by instrument at 61 parts, a figure arrived at after eleven years of argument and never revised, although the Stairwell has been measurably wetter since Year 134.

The Catalogue of Absences and subsidiary holdings

Under Clause 47 of the Third Concordance, the Third Catalogue maintains the Catalogue of Absences — a register of subjects the Tower has determined not to hold — and it is through this instrument that the Catalogue exercises jurisdiction over what it does not contain. The Catalogue of Unheard Melodies and the Catalogue of Unheard Echoes are subsidiary to it and are bound in the same grey board.

The Catalogue's relation to absence is administrative rather than philosophical. A subject is entered as absent only after the Pursuit of Specific Holdings has returned an inventory, and the inventory must be filed even where it records nothing. Readers consulting an absence entry are entitled to see the inventory. Most do not.

Controversy: the scope of the Annex

Scholarly opinion divides on whether the Third Catalogue is properly a recension or a distinct institution that has absorbed a recension. The Idealist Catalogue holds the former position and cites the continuity of folio numbering across the Second and Third Catalogues as decisive. The Prolegomena to the Incomplete Catalogue argues the latter, observing that the Third Catalogue's Annex on Material Authenticity applies retroactively to Second Catalogue entries that have been re-accessioned, "an act of adoption, not of continuation" (Prolegomena to the Incomplete Catalogue, §14).

A third view, advanced in the Collected Prefaces to the Unfinished Catalogue and largely unregarded, holds that the question is not decidable from within any recension and should be referred to the Third Spiral for a ruling. Circular 44-A, issued 14 Thermidor, Year 117, declined to rule and referred the matter back.

Recension disputes and the Indexers

Disagreement between the Third Catalogue and the Indexers is chronic. Clause 7.α of the Third Concordance recognises the Indexers' role in the maintenance of the catalogue without specifying where their indices end and the Catalogue's own apparatus begins. In Year 122 a duplicate index of Floor 640 was produced by each body within the same month; both were accessioned, and both remain in use. The discrepancy between them has never been reconciled, though it is small.

The Archival Submission procedure requires that any folio offered to the Third Catalogue be accompanied by a custody statement from the Archivist Cadre, in accordance with the principle of Custody Before Catalogue. Submissions without one are held at the receiving desk and, after ninety days, returned. The desk on Floor 331 holds four hundred and six such folios, some since Year 138; the Custody Before Catalogue principle is not retroactive to submissions received before it.

Physical description

Active folios of the Third Catalogue are bound in grey board over oak, in volumes of no more than four hundred leaves, and shelved by aperture rather than by subject. The binding is replaced when the spine fails, which on the Damp Stairwell side of the building occurs at a rate of one volume in nine each decade. Withdrawn folios are not destroyed but transferred to the Catalogue of Unfinished Bridges, where they are filed by span.

Staff are reminded that the reading lamps on Floors 300 to 340 are lit by the Aperture Stair and must be extinguished before the stair is closed for the night, whether or not readers remain.