The Aperture Sigma Press

The Aperture Sigma Press is a fixed-body mechanical press of the vertical-screw class, housed in the north bay of Aperture Sigma on Spiral 44 and held by common consent to be the oldest continuously operated instrument of its kind in the recorded reaches. It is not a printing press. The Aperture Sigma Press impresses a subject with a temporary seal — an aperture mark — assigning it a provisional place in the catalogue before any substantive entry exists. The press converts an unclassified thing into a thing that may be described later. It does not describe it. This distinction is inscribed on the frame above the platen in letters of hammered brass and is, by most accounts, the single most misread instruction in the building.

Its output — the pre-catalogued potentialities — is enumerated floor by floor at Aperture Sigma-7 under the standing protocols of the Annual Register Sigma-14,022.

Construction and operation

The Press occupies a bed of blackened basalt 2.4 metres square, cut to receive the platen in a single rebate. The screw is a triple-threaded wrought assembly of undetermined age; metallurgical sampling has twice been refused on procedural grounds. The operating controls for the lathe are housed within the Aperture Sigma console, and the press itself is driven from the same console, which has been the source of a persistent maintenance grievance. The operator must stand at the console, therefore, with the subject held beneath the platen by hand.

An aperture mark is valid for one hundred and nineteen days from impression. It confers provisional catalogue standing only: a marked subject may be referenced, listed, and quarrelled over, but may not be described. After the hundred and nineteenth day the mark fades to a pale grey and the subject reverts to unclassified status, retaining its number but not its name. The Reversion of Nine Hundred Tray, an incident of the winter of Year 3908 in which a single missed recension returned three hundred and sixty subjects to namelessness in one afternoon, remains the standard illustrative case in instruction.

Relationship to the Large-Scale Conceptual Press

The Aperture Sigma Press is frequently confused with the Large-Scale Conceptual Press of the Central Press Hall, and the confusion is not wholly accidental. The two instruments were for forty years administered by the same sub-office and share a numbering sequence for their impressions, with the consequence that the early marks of the Aperture Sigma Press bear numbers indistinguishable from those of the Central Press. The Large-Scale Conceptual Press operates at the scale of categories; the Aperture Sigma Press operates at the scale of single items, and poorly.

The distinction was ruled upon — inconclusively — in the matter of a contested impression of Year 3722, when a subject marked at Aperture Sigma was found to have been described in the Central Press Hall nine days before the mark was applied. The description was six days older than the thing it described, which the Registrar of Precedent recorded as "an arithmetical indecency" but was unable to remedy.

Scholarly disagreement

Whether the Aperture Sigma Press generates Sigma Pulses in the course of ordinary operation is disputed and, given the present state of the instrumentation, likely to remain so. The Sigma-Class position, set out in the Third Concordance as amended by the Aperture Sigma Reinforcement, holds that every platen-stroke produces a pulse and that the pulse is dissipated at Aperture Sigma-12 in the ordinary way. The Dissipation Office has long objected that no pulse has ever been detected as originating at the press, and that the recorded pulses attributed to it are consistent with background sources in the chamber.

"A pulse not observed is not a pulse unproduced; it is a pulse unobserved, and the distinction is the whole of our discipline."

— Third Concordance, Annex 4, Marginalia of the Registrar Voight

The counter-position was stated more bluntly in the Dissipation Office's annual return for Year 4007, which described the press as "a hammer with ambitions." No reconciliation has been attempted since.

The Voight grievance

Between Years 4009 and 4013 the operation of the press was the subject of a formal grievance lodged by the junior archivist Anselm Voight against the Office of Platen Maintenance. Voight's complaint was that the platen had not been resurfaced since Year 3981, that impressions taken in the lower registrations were three parts in a hundred too shallow to hold a mark past the fortieth day, and that his repeated memoranda on the subject had been answered with a standing circular about "the robust tradition of the instrument." The Office replied that the surface of the platen was original and that original surfaces are not altered.

The dispute was settled under Concordance 88 by a compromise in which the platen was not resurfaced and Voight was reassigned to the Aperture Sigma-7 stairwell. The vault below the north bay is still required to be kept free of pigeons, a condition attached to the settlement at the insistence of the Office and never explained in any surviving recension.

Visiting

The Press may be inspected on the eleventh and twenty-third of each month, between the second and fourth hours after the bell. Visitors must not touch the screw, must declare any aperture marks carried about their person, and must be gone before the platen is released. The north bay is unheated.