Volume I: Atmospheric Substrates

Volume I: Atmospheric Substrates is the first recension of the foundational registry of the Tower, treating the composition, classification, and custodial disposition of all matter suspended in interior air. It is held in the Office of Atmospheric Cataloguing on Floor 88 (no name; the door is marked only with a barometric seal) and is consulted chiefly by the Atmospheric Integrity Guild and by clerks of the Office of Atmospheric Integrity, though the Materials Board retains a standing right of excerpt. Unlike Volume II: Materials and Mediums, which governs solids and instruments, Volume I concerns only what is airborne, and it opens with the much-quoted formula of its first clause: "That which will not stay put is not therefore ungoverned." A full set of the first recension comprises eleven fascicles; nine survive intact, one is water-damaged from fascicle 7 onward, and one is missing.

Composition and Recensions

Volume I was compiled in the years following the first surveys of the Western Atmospheric Spiral, and its earliest fascicles retain the surveyors' habit of describing air by what it carried rather than by what it was. The second recension, undertaken under warrant of the Fourth Concordance, reorganized the whole into four classes — the Settled, the Drifting, the Vestigial, and the Unassigned — and it is this fourfold division that later instruments were built to detect, including the Ambient Reality Probe, whose sampling heads are calibrated to distinguish only the first three. The Atmospheric Intent Meter is not sanctioned by Volume I at all, a matter taken up below.

Fascicle 2 governs the classification of Vestigials and cross-refers to the custodial functions of the Ambient Reservoirs, whose mandate over emotional and cognitive substrates is set out in their own instrument of foundation. Volume I does not define what a Vestigial is; it defines only how a Vestigial is to be indicated, sampled, and, where necessary, laid down in the presence of a witness. This division of labour has held for fourteen recensions and is regarded as one of the archive's more durable arrangements.

The Question of Intent

The principal scholarly dispute attaching to Volume I concerns whether the registry can be said to classify intent. Fascicle 6, in the clause governing drifting substrates, admits "substrates that persist in a direction," a phrase the Atmospheric Integrity Guild reads as descriptive of momentum and the Office of Atmospheric Cataloguing reads as descriptive of purpose. The dispute is old enough that both offices cite the same clause in support of opposite rules of practice.

"A substrate that persists in a direction has not thereby declared one."

— Seventh Concordance, Annex β-12, marginal gloss

The gloss appears in the hand of the annex's second reviser, whose name is not recorded, and it has been reprinted in every subsequent recension without comment. The Atmospheric Intent Meter, an instrument of the Measurement Directorate, records readings that the Office of Atmospheric Cataloguing declines to enter in the register, on the ground that Volume I provides no field for them. The Guild has twice petitioned for an amendment; the petitions are in the file and the file has not moved.

Application at Atmospheric Reclamation Station 7

Volume I is the operative instrument at Atmospheric Reclamation Station 7, where its schedule of tolerable concentrations is consulted daily and its measurement conventions are followed with a rigour that the station's own log describes, without evident irony, as "devotional." The station's oversight by the Guild on matters of atmospheric consistency rests on Concordance 7123, which itself cites Volume I, fascicle 4, clause 9, without quoting it. In the winter of TY 7124 the clause was found to have been misquoted in the station's standing orders for a period of some forty years; the correction was made and the misquotation retained in an appendix, as is customary.

Infractions under Volume I are heard by the Materials Board when the substrate is recoverable and by the Office of Atmospheric Integrity when it is not. The distinction is not always obvious at the outset. A case of the second winter of TY 7123, concerning a quantity of Phantom Pollen that had settled into a stairwell on Floor 422 ('The Granularity') and was claimed by no fewer than three custodial bodies, was heard twice: once as a settling matter and once as a dispersal matter, with different findings. Both findings stand.

The Missing Fascicle and Its Reconstructions

Fascicle 11, treating the Unassigned class, is not held by the Office of Atmospheric Cataloguing. It is known to have existed: it is cited in the Ninth Concordance and in three internal memoranda of the Measurement Directorate. The Office maintains that its contents were "provisional and superseded," and the Guild maintains that they were neither. Four independent reconstructions have been attempted from the citation trail; they agree on the fascicle's title and on the number of its clauses (seventeen) and on nothing else.

The most recent reconstruction, prepared by a clerk of the Office named Harrow Vell, was submitted in TY 7122 and rejected on the ground that it did not reproduce the original's pagination. A marginal note in Vell's working copy, dated eleven days after the rejection, reads "The pagination was the point." The note is the entire surviving record of Vell's position and is quoted in every subsequent survey of the question.

Inventory of the Surviving Fascicles

The following inventory is reproduced from the Office's shelf-list, with condition as of TY 7124.

• Fascicle 1 — General definitions; the will-not-stay-put formula. Sound.
• Fascicle 2 — Vestigials; custodial cross-reference to the Reservoirs. Sound.
• Fascicle 3 — Tolerable concentrations; the schedule at issue in 7124. Annotated.
• Fascicle 4 — Measurement conventions; clause 9 misquoted, see above. Sound.
• Fascicle 5 — Settled substrates. Sound.
• Fascicle 6 — Drifting substrates; the direction clause. Two leaves supplied in a later hand.
• Fascicle 7 — Spiral survey notes; water-damaged from clause 4 onward. Readable to clause 11.
• Fascicle 8 — Calibration cross-references. Sound.
• Fascicle 9 — Unassigned; provisional headings only. Sound.
• Fascicle 10 — Index of indices. Sound.
• Fascicle 11 — Unassigned; not held.

Consultation of the surviving fascicles requires a written introduction from a Librarian's office and may not be conducted in the reading room of Floor 88 during the hour preceding the barometric reading, when the instruments are uncovered.

Relationship to Later Instruments

Volume I's authority over the calibration disputes of the Western Atmospheric Spiral is derivative rather than original: the primary referent for such disputes is Western Atmospheric Spiral Calibration, which cites Volume I only for its schedule of tolerable concentrations. The Atmospheric Readiness Assessment conducted per Atmospheric Protocol Sigma likewise invokes Volume I for definitions and no more, though in practice assessors quote fascicle 1 at length in their preambles, a habit the Office has ceased to discourage. The Report on Atmospheric Anomalies (TY 7124) devotes its fourth appendix to the question of whether the Unassigned class should be abolished, and concludes that it should not, since abolition would require the missing fascicle.