Atlas of Nocturnal Anatomy

Definition and scope

The Atlas of Nocturnal Anatomy is a cartographic work catalogued under the general heading of anatomical atlases, though its subject matter is not anatomy in the sense ordinarily meant by the Scriptoria of Dissection. It depicts, across eleven plates, the internal arrangements of structures that are only present between the onset and lifting of official Tower-night. The plates are numbered I through XI, though plate VII is missing from all known copies and is believed never to have been cut. The Atlas is most frequently consulted in connection with the assessment of the Luminal Gradient, and several of its plates are reproduced, at reduced scale, in the Manual of Luminal Gradients as reference figures. It is held on the Shelf of the Ninth Scriptorium and is available for consultation upon written application to the Proctor of the Ninth, provided the application is submitted during daylight hours and does not mention plate VII by name.

Contents

The Atlas is organized into three groups. Plates I–IV, termed the Superficial Series, record the external topography of nocturnal structures as they present to an observer entering a darkened chamber. Plates V, VI and VIII–X, termed the Deep Series, record arrangements of tubes, chambers and hinge-lines observed after the removal of the superficial layers. Plate XI, standing alone, is titled simply "The Witness" and depicts a figure seated at a desk with its back to the reader. The nomenclature used throughout follows the conventions established in the Concordance of Nomenclature, Annex 3, with the result that several structures bear names which appear, to the uninitiated, to be errors. The cribriform patience, the iliac weather and the second reluctance are all standard designations and are not to be corrected in the margins, a rule enforced with particular vigor by the Scriptorium of the Ninth.

Provenance and dating

The Atlas carries no colophon. Its earliest recorded appearance in the holdings is an inventory of the Shelf of the Ninth dated to the winter of Cycle 412, where it is listed as "one atlas, nocturnal, unbound, in poor condition." The condition note is believed to refer to the binding rather than the plates, as the plates survive in excellent state in all three known recensions. Attribution has been the subject of prolonged dispute. The prevailing view, associated with the Proctor of the Ninth in Cycle 455, holds that the Atlas was compiled by the Scriptorium collectively and that the hand appearing on plates V and VIII is that of a single scribe working over a period of no fewer than four years. A minority position, advanced in Opinion 881, In re: The Whispering Atlas, argues that the Atlas predates the Scriptorium of the Ninth entirely and was merely housed there, though this opinion concerns the Whispering Atlas primarily and addresses the nocturnal work only in passing.

Relation to the Aperture traditions

The relationship between the Atlas and the broader tradition of Nocturnal Aperture study is one of mutual dependence and occasional institutional friction. The Department of Circadian Metrics treats the Atlas as a secondary source, preferring direct measurement via calibrated apertures, while the Scriptorium of the Ninth regards the Department's readings as insufficiently attentive to the arrangements the plates record. This disagreement produced the incident of the winter of Cycle 468, in which a surveying party from the Department entered the Ninth Scriptorium to take readings from plate VI by the light of a borrowed aperture and were found, the following morning, to have taken the readings from the plate's reflection in a polished tray rather than from the plate itself. The error was not discovered for eleven days, and the resulting figures were cited in three separate reports before being withdrawn. The Third Concordance addresses the matter obliquely, classifying the Atlas as a reference instrument under Annex 7 and thus subject to the same calibration requirements as the apertures themselves. Whether an atlas can be calibrated has never been satisfactorily answered, and the question is said to have ended the career of at least one junior Proctor.

Scholarly disagreement

The principal dispute concerns plate XI. The Proctorial school holds that "The Witness" is a conventional figure representing the observer and carries no anatomical content, and that its inclusion is a holdover from an earlier and less rigorous arrangement of the plates. The Scriptorial school counters that the figure is drawn with the same precision as the Deep Series and that its posture — specifically, the angle of the neck — corresponds to a structure depicted in plate IX but named nowhere in the text. A third view, recorded in a marginal note of uncertain date on the flyleaf of recension B, holds that the figure is not seated at a desk but is himself the desk, and that the plates should be read from beneath. This note is unsigned. The two schools have not reached accord, and the matter is periodically reopened at the Concordance revisions. Readers consulting the Atlas in conjunction with the Manual of Luminal Gradients are advised that the two works disagree about the identification of the second reluctance, and that the Manual's reading is the one accepted for assessment purposes.

Access and conditions of use

The Atlas may not be removed from the Ninth Scriptorium. It may not be photographed by any means requiring a flame. Consultation is permitted between the second and ninth hour of the working day, and a clerk is required to be present throughout, though the clerk's duties are understood to include no more than witnessing that the reader does not turn plate XI upside down. Visitors are reminded that the shelves of the Ninth are not to be used for the storage of coats, and that any coat found there will be catalogued.