Attenuation

Attenuation is the general term for the Tower's several procedures of reduction: the removal of surplus intensity, surplus sound, surplus duplication, and — in the disputed cases — surplus meaning, from material passing into the permanent archive. The word is used loosely in common speech to cover three distinct operations (Primary Attenuation, Procedural Attenuation, and the lesser "attenuation of record" described below), and has been formally defined no fewer than six times. None of the six definitions survives the next in full. The operative clause remains Fourth Concordance, Article 2, which declines to define the term and instead states where the work is done: "Attenuation is that which is conducted on Floors 88 through 91, and elsewhere only by licence" — Fourth Concordance, Article 2.

Physical and procedural attenuation

The principal division recognised throughout the Tower is between the physical attenuation performed in the Attenuation Galleries and the codified, non-physical attenuation of administrative and legal matter set out under Procedural Attenuation. Physical attenuation (or Primary Attenuation) is conducted within the Attenuation Galleries on Floors 88–91, where raw Percolate and Archival Dust undergo a seven-stage reduction. Its acoustic field is generated by the inverted harmonic bleed of the Attenuation Lens, an instrument of considerable age and unforgiving maintenance. Procedural attenuation applies the same first principles to rulings, filings, petitions, and testimony, chiefly by the removal of emphasis prior to review.

The two branches have never agreed on precedence. The Office of the Register maintains that physical attenuation is senior, having produced a measurable result at least once; the Bureau of Procedural Redress counters that procedural attenuation must precede it, since nothing may be reduced physically before it has been reduced in the record. The Axis of Attenuation has declined to intervene in either direction. The compromise, reached in the winter of the year the gallery roofs were reslated, is that the question is decided floor by floor, and is not raised on Floor 90.

The attenuation of record

A third operation, less frequently discussed, is the attenuation of record: the reduction of a thing's description to the length at which it can be stored without loss of consequence. Where physical attenuation strips surplus intensity, the attenuation of record strips surplus particularity. A single petition concerning the noise of a stair may pass through procedural attenuation in the morning and return from the Scriptorium of Reduced Texts by evening as a line of eight words, which is then filed as though it had always been those eight words.

The practice is defended in Ninth Concordance, Annex 2, on the grounds that "a thing attended to at full length will be attended to again, and the archive has no second floor for it" — Ninth Concordance, Annex 2. Its critics are numerous and their filings are long. Clerk Emeric Vantle, whose grievance over the reduction of his 117-page submission on stairwell ventilation to the phrase "ventilation: adequate" is preserved as an example of form, argued for six years that the operation was indistinguishable from forgetting. His case was reduced, on final appeal, to "grievance: heard."

Harmonic instability and the limits of reduction

Attenuation is not universally applicable. Harmonically unstable phenomena resist it, and are processed under the supervision of the Axis of Attenuation, whose rulings on instability are final and, by convention, unrecorded. What cannot be attenuated is held instead: the Resonant Damping Mesh serves as a temporary restraint for materials awaiting the galleries, and the Dampening Protocols govern how long such material may be kept before it must either be reduced or declared permanent.

The distinction between attenuation and damping is the subject of the archive's longest-running dispute. Damping suppresses; attenuation removes. Fifth Concordance, Article 11, holds that the difference is one of intent and therefore administrative; Eighth Concordance, Article 11, holds that it is one of physics and therefore not the archive's business. Both articles are numbered 11. Neither has been withdrawn. In practice the galleries use the terms interchangeably in speech and never in writing, and the Office of the Register has ruled that any filing which uses both terms in one paragraph must be returned unopened, which it is.

Insulation and silence

The Attenuation Galleries are the primary source of architectural silence in the Upper Reaches, a circumstance attributed to the galleries' own insulation rather than to any ordinance. The order's position is that silence is a by-product and not an objective, and that requests for quiet should be addressed to the relevant floor rather than to the galleries. The silence is nevertheless much sought. Arclight Sconces along the approach corridor are kept at the lowest setting required to see the doors, and the Ocularium, operational base of the Lens programme, is entered without knock.

Portraits of predecessor Luminaries are transferred to the galleries for contextual attenuation following the Great Dimming, a transfer that remains incomplete and is not discussed with the families. Subordinate copies of the Leger of Draws are kept on Floor 89 against the loss of the primary, though the primary has never left the Register, and the copies have never been consulted.

Maintenance and standing instructions

The Attenuation Lens requires bi-weekly polishing, a duty discharged by the Keeper's Second Assistant and entered in the day-book without remark. Ongoing Monitoring of the Attenuation Galleries records the standing readings; the galleries themselves record nothing, which is considered proper.

Visitors to Floors 88–91 are admitted by written appointment only and are asked to arrive having already said what they came to say. Reading aloud is permitted; humming is not.

See also

• Attenuation Galleries
• Primary Attenuation
• Procedural Attenuation
• Attenuation Lens
• Axis of Attenuation
• Filtering
• Attenuated Cultivar