Secondary Atria

Secondary Atria are those atria which, under the classification set out in Third Concordance, Annex A, Clause vii, are encountered after the first atrium on any floor during a standard descent protocol. The designation is purely ordinal and carries no implication of size, ornament, or architectural merit; a Secondary Atrium may be the largest chamber on its floor, and frequently is. What distinguishes it is sequence. Once the Primary Atrium has been logged and sealed, every subsequent atrium on that floor is Secondary, however many there prove to be, and however long the descent takes.

The category was not named until the recension of 9-441-Devar, when the surveyors of the Atrium Architecture office found themselves unable to file returns from floors whose atria numbered above nine and whose forms provided columns for only two. Secondary was adopted as a catch-all, with the understanding — never formally withdrawn — that it would be subdivided at a later date.

Definition and numbering

Secondary Atria receive no independent designation. They are recorded by the number of their floor plus a serial suffix in descending order, thus 41-Secondary-1, 41-Secondary-2, and so on until the next stairwell or shaft interrupts the count. Secondary (Plumb-Line) Measurement is used to establish the serial where a floor's boundaries are disputed, which is most of them. The plumb-line is read from the underside of the Primary Atrium's threshold stone; where no threshold stone survives, the measurement is taken from the memory of the last surveyor to have stood on it, and is marked in the register with a small superscript 'm'.

Floors bearing a designation ending in 0 or 5 are subject to the jurisdiction of Public Atria, and their Secondary Atria are consequently obliged to display the Notice of Accessions by the second bell after opening. This obligation has caused persistent friction between the curators and the Atrium Curators, who maintain that a notice posted in the second atrium of a floor is not, in law, posted on that floor at all. The dispute was referred to the Sixth Concordance and returned unresolved.

"A notice affixed beyond the first threshold shall be deemed affixed to the floor only where the first threshold has been found impassable, and the finding of impassability shall be made in writing before the notice is affixed, and not after."

— Third Concordance, Annex A, Clause xii

Atmospheric and acoustic behaviour

Secondary Atria are not uniform in their atmospherics. Those reached by way of the Pneumatic Atria inherit regulated pressure and the sound-dampening baffles common to that class, and are tolerably quiet. Those adjoining Shattered Atria do not, and the acoustic environment of a Secondary Atrium in a fragmented zone has been described by the Historian-Errant Kole as "a conversation held at both ends at once, with neither end listening." Kole's survey of the Chaudhry Stair, conducted over the winter of 12-1004-Ember, recorded eleven Secondary Atria in a vertical span of forty metres, of which four were judged to be the same atrium encountered repeatedly from different approaches. The finding was not contested; it was simply filed.

Where a Secondary Atrium abuts a Whisper Shaft, the shaft's emissions are to be recorded in the atrium log at the top of the hour. The log is not to be read aloud in the atrium. This rule dates from the Contemplative Atria Incident of 12-997-Aleph, after which the Calibrated Atria were fixed with Absence Anchors at their principal transitions and the reading of logs in enclosed atria was prohibited by the office of the Sixth Librarian.

Administration and the Serials Dispute

Responsibility for the Secondary Atria falls to the Atrium Curators, save where a Secondary Atrium lies on the route of a conduit of the Pneumatic Conduit Array, in which case the conduit's wardens hold precedence for purposes of maintenance only and not for purposes of naming. The distinction matters. In 8-703-Ilan a warden of Conduit Alpha renamed the fourth Secondary Atrium of floor 12 a "transfer lobby," painted the designation on the arch in white lead, and was thereafter unable to obtain a surveyor willing to certify the floor. The paint was removed in 8-709 by order of the Curators; the arch has never been recertified, and descents through floor 12 are now recorded with the annotation "lobby, disputed."

A parallel feud concerns the serials themselves. The office of Secondary Instrumentals holds that Secondary Atria should be numbered from the uppermost downward, as the descent encounters them; the Phenomenological Spire holds that they should be numbered from the floor's far wall inward, on the grounds that the far wall is more stable than the descent. Both positions are supported by annexes of equal standing. No reconciliation has been attempted since 11-882-Meridian, when a joint commission sat for nine days and produced a report consisting of a single sentence, which was itself later challenged as apocryphal.

Register of common types

Surveyors distinguish the Secondary Atria loosely, by what they contain rather than by where they fall. The following types are the most frequently returned:

• Threshold Secondary — an atrium whose only function is to admit passage to a third; typically unfurnished.
• Accumulative Secondary — an atrium in which objects abandoned by earlier descents have gathered; must not be cleared without a Curator's writ.
• Conduit Secondary — an atrium traversed by secondary conduits of the Pneumatic Conduit Array, warm to the touch at the joints.
• Attendant Secondary — an atrium containing a table, a lamp, and a chair, and no record of who placed them there.
• Anonymous Secondary — an atrium whose serial cannot be established because the descent that recorded it was not a standard one.

The fifth type is the despair of the register. It is estimated that some four hundred Anonymous Secondary Atria are entered in the rolls of the Western Atrium alone, and that a majority of them are the same three chambers.

Scholarly disagreement

The chief question dividing the offices is whether Secondary Atria are secondary to the Primary Atrium of their own floor, or secondary in some larger sense — a rank in a hierarchy that the Tower has never published. The Atrium of Authority has ruled twice on the matter, first that the term "secondary" denotes sequence only and must not be read as a statement of precedence, and second, eleven years later, that precedence is implied by sequence and the ruling of eleven years prior should not be cited. Both rulings remain in force. In practice, curators cite whichever is convenient, and the surveyors, who must live with the results, cite neither.

Visitors are advised that a Secondary Atrium is not a place to wait in. The ruling of the Atrium of Authority on this point is unambiguous, and is posted, as required, at the first threshold.