Chrono-Logical Engine

The Chrono-Logical Engine is a cumulative adjudicative mechanism, distributed across Floors 299 through 305, that resolves discrepancies between the order in which events are recorded and the order in which the archive permits them to have occurred. It is not a clock and does not measure duration; the Engine's office, in the phrasing of the Ninth Concordance, is "to determine not when a thing happened but when it may be said to have happened" (Ninth Concordance, Annex 2, clause 14). The distinction is not ornamental. Roughly a third of the Tower's contested holdings turn on it.

The Engine is commonly confused with the Axiomatic Engine of the Stacks of Possible Geometries, and the two offices have never been on cordial terms about it. The confusion is understandable: both are assembled from geared brass, both are tended by hereditary staff, and both will emit a bell in the presence of an unresolvable proposition. The Office of Distinct Mechanisms has issued four circulars on the subject, the fourth of which observes, with visible fatigue, that "a bell is not a signature" (Office of Distinct Mechanisms, Circular 4, 611 M.E.).

Construction and calibration

The Engine's active component is a train of 299 ratcheted drums, one for each year of the standard recension period, mounted on a single axle in the Well of Deliberative Machinery. Each drum carries a notch cut to the profile of a specific canonical uncertainty; the drums are keyed from the Vault of Conditional Forms on Floor 299, from which the Engine draws its working premises and to which any drum cut more than forty years ago must be returned every seventh winter for refacing. This is the purpose of the well-known maintenance window between the fourteenth and twenty-second of Frostmonth, during which the Well is closed to foot traffic and the drums are audible two floors in either direction.

Arguments are fed to the Engine as paired slips. The Engine advances one drum per turn of the axle, and the first slip to fall from the sorting tray while its drum remains engaged is held to have precedence. The procedure sounds crude and is defended fiercely. "The Engine does not reason," wrote the then-Keeper Adelard Vess in 588 M.E.; "it declines to reason, in order, and the order is the finding" (Vess, On the Reluctance of Mechanisms, fol. 22r).

The Sympathetic arrangement

Since the refitting of 604 M.E. the Engine has been paired with a Sympathetic Resonance Engine installed on an adjacent plinth, which identifies latent logical linkages between active ordinances and dormant archival clauses before the drums begin to turn. The pairing is imperfect. The Sympathetic Resonance Engine was calibrated on Floor 118 for the weekly recalibration of the Engine of Fractional Momentum, and its measurement tolerances were never intended for the Well's humidity. A supplementary Vestigial Logic Engine acts as a check on the resonance readings, though its output is increasingly treated as advisory; the Vestigial Logic Engine Body has not issued a complete determination since 631 M.E.

In 618 the Chrono-Refractive Spectroscope Adjudication Committee was invited to certify the Engine's capture aperture for audit purposes, and sent observers instead. The resulting report recommended that the aperture be plated, and a quantity of Vitreous Chrono-Plating was duly applied. The plating fogged within a season. It was not removed, because the Committee had by then certified the batch, and a certified plate may not be struck without a further sitting of the Committee, which has not been convened on the matter since.

Application in audit

The Engine's principal use is procedural. Every Chrono-Forensic Audit conducted under Chrono-Refractive Theory opens with a determination slip bearing the Engine's seal; without it, findings are inadmissible and the audit is recorded as "preliminary pending the axle." Licensed Spool-Wrights also consult the Engine between secondary calibrations of Chrono-Resonance Spools, a practice the Guild permits but does not endorse.

The Vess–Marroquin dispute

Scholarly disagreement over the Engine is old and, by the standards of the Concordances, restrained. Third Concordance holds at Annex 5 that the Engine's precedence rule "is of universal application, and no holding shall be ordered otherwise." Eleventh Concordance, at Annex 1, holds that the rule applies only to holdings entered after the Engine's own founding, which it dates to 402 M.E. The two annexes have never been reconciled, and the Concordance Revision Committee has declined to sit on the question eleven times.

The practical consequence fell on the clerk Ondra Marroquin, who in the winter of 641 sought to have a shipment of recension slips from Floor 302 reordered under the Eleventh's narrower reading. The Engine, consulted first, returned a determination under the Third. Marroquin appealed, on the ground that the appeal itself had been entered after the founding and therefore belonged properly to the Eleventh. The Appeal Tribunal found for Marroquin and instructed the Engine to apply the Eleventh to its own determination. The Engine applied the Third to that instruction. It has been applying the Third to every instruction addressed to it since, including the Tribunal's subsequent orders, and the Tribunal has adopted the position that the matter is now before the Engine.

"The Engine is not in contempt. The Engine is in sequence. There is a difference, and we have not yet established which one we are looking at."

— Ondra Marroquin, marginal note to Appeal Docket 641/19

Access and standing prohibitions

The Well of Deliberative Machinery is open to accredited researchers on the second and fourth Thursdays of the month. The Engine itself may be viewed but not addressed. Visitors are reminded that the drums are not to be counted aloud, a rule introduced after the counting incident of 597 and reaffirmed in every recension of the Well's standing orders since.

No determination of the Engine has ever been overturned outright. Several have been superseded, a number have been set aside, and one — the celebrated determination of 566 concerning the disposition of Floor 304 — has been listed in three separate registers as both suspended and in force. The Office of Distinct Mechanisms regards this as its most successful result.