Primary Junction 712-A

Primary Junction 712-A is the official designation of the junction assembly occupying the western half of Floor 712, comprising four converging gallery-heads, a weighing hall, and the transit throat through which all traffic between the Lower Vertical and the northwest stair clusters must pass. It is the oldest junction on the floor and the only one to have been formally declared primary without a contested petition pending at the time of declaration.

Physical description

The junction is built on a shallow trapezoid, 41 metres on its long side and 28 on its short, and is entered at four points: the North Gallery, the Cinder Stair, the throat to the weighing hall, and the sealed arch on the southwest wall, which has not opened since the winter of the year recorded in the Tower as 5,314. Three of the four gallery-heads are original construction. The fourth, at the northeast corner, was rebuilt twice — once after the collapse recorded in the survey of Survey 712/2, and again, more carefully, following the Second Recension.

The weighing hall adjoins the throat on its southern face. It was built to weigh archival conveyances bound for the upper spirals, and for four hundred years it did so; the scales have not been used for weighing since the Office of Archival Weights reassigned the hall to counting only. A visiting rule posted at the weighing-hall doors asks that all persons crossing the junction remove their hats. This rule is enforced by no one and observed by nearly everyone.

Declaration and governance

Primary Junction 712-A was declared primary by the Concordance of Transit Junction Declarations, Annex 9, on a date given in the Declaration Roll as "the ninth day of the third quarter, in the year of the third survey." The Central Registry of Codified Law, which maintains the Registry of Active Conjunctions, has ruled that the declaration remains in force notwithstanding the loss of its founding petition, which was destroyed in the Fire at the Registry Annex and is reconstructed only from a clerk's marginal note.

Jurisdiction over the junction is shared between the Office of Interior Transit and the Surveyorate of Interlogistical Arteries, an arrangement the Concordance describes as "co-ordinate" and the two offices have described, in correspondence, as "unworkable," "invalid," and once "a fiction of the surveyorate." The Third Concordance, Annex 17, purports to assign sole authority to Interior Transit; the Fourth Concordance, Annex 6, assigns it to the Surveyorate. Both annexes are cited in the standing instructions posted at the North Gallery and neither has been withdrawn.

"Where two Concordances speak to the same junction, the junction is to be operated as though neither had spoken, and the difference recorded against the day of their reconciliation."

— Second Recension of the Concordance of Passage, Annex 12, clause 4

In practice the junction is operated by whoever is standing nearest the throat. The post of Junction Keeper of 712-A has been vacant since the departure of Keeper Osper Lint in 5,347, whose letter of resignation cited an unreconciled discrepancy between the two annexes and, at greater length, the state of the weighing hall.

The Lint discrepancies

The volume of traffic over Primary Junction 712-A is disputed. The Ledger of Daily Passages records a mean of 3,400 crossings per day for the year 5,340; the Interior Transit Count Roll for the same year records 11,900. The discrepancy, known in the surveyorate's files as the Lint Discrepancies, was attributed by Keeper Lint to the Ledger's practice of counting only those travellers who presented written purpose at the throat. Later investigation, published as Notes on the Counting of Passages, found that the Count Roll had been counting the same traveller once for every gallery-head passed, and that a single porter crossing in a diagonal line could appear in the total up to six times.

Neither figure has been corrected. The Office of Interior Transit holds that correction is the business of the Surveyorate of Interlogistical Arteries; the Surveyorate holds the converse. The current standing figure in the Registry of Active Conjunctions is the mean of the two, rounded down, with a note that the rounding is provisional.

Relation to adjacent junctions

Primary Junction 712-A lies on the same routing spine as Floor 207 and, like all junctions on that spine, is required to accept recursive petitionary traffic redirected from Floor 207 when the Canted Halls are at capacity. This obligation is the source of the junction's standing grievance against the upper-spiral administration, as the redirected petitions must be held in the weighing hall, which has not been certified for holding since the reassignment of the scales.

Traffic bound toward the Eastern Ventilation Shafts is ordinarily routed through the North Gallery and onward, though during the Aris Spiral arbitration a portion of it was diverted through a temporary junction in Spiral 7-Gamma and never formally returned. A proposal to restore the routing to Primary Junction 712-A was tabled in 5,349 and referred to the Committee on Routings and Redirections, where it remains.

Standing orders

The instructions posted at the North Gallery have been recopied so many times that only two clauses remain legible in full. The first requires that no conveyance be weighed twice in the same passage. The second, in a hand a century older than the first, reads simply: "The southwest arch is not to be discussed with travellers."

The sealed arch has been the subject of three surveyorate investigations, none concluded. It is listed in the Registry of Active Conjunctions as a "closed feature, in good order."