Floor 407, “The Hall of Mirrors”

Floor 407, “The Hall of Mirrors” is a floor of the Tower given over almost entirely to reflective surfaces, and to the offices and instruments that have accumulated around them. It is best known as the seat of the Bureau of Apparent Duplication, but it also houses the workshop floor of the Reflector Guild, the south annex of the Hall of Adjudication, and the optical calibration bench maintained under licence from the Bureau of Metrological Calibration on Floor 317. The floor's name is inscribed on the stair-head plaque in the formulation adopted by the Concordance of Floor Names, which records it in the singular—“The Hall of Mirrors”—though no single hall of that description has ever been identified on the floor plan.

Topography and disposition of the glass

Floor 407 is a shallow rotunda roughly 90 metres across, divided by eleven radiating walls into chambers of unequal size. The glass is not hung on the walls but set into them, in some chambers to a depth of four courses. A visitor walking the outer corridor passes, in sequence, a wall of plane mirrors; a wall of mirrors ground to slight convexity; a wall of smoked glass that returns a dimmed image; and, at the north-east arris, a wall of mirrors that have been deliberately clouded and return nothing that can be used.

The last of these is not defective. The Bureau of Apparent Duplication maintains the Clouded Wall under standing instruction and has repelled three attempts by the Reflector Guild to have it reground, most recently in the winter of the year the Guild's petition was read into the record as On the Waste of Good Glass. The Bureau's answer, entered the same session, was a single line: “A mirror that shows nothing is doing work.” The petition was not renewed.

Floor 407 is entered from the stair-head of the Hall of Passages and is not a thoroughfare. Visitors are asked to leave their coats at the door of the second chamber, since the corridors are narrow and the glass is old.

The Bureau of Apparent Duplication

The Bureau of Apparent Duplication occupies the central chambers and the whole of the eastern arm. Its remit is the registration of things that appear twice and are not the same thing—a category the Tower has never succeeded in narrowing. The Bureau's registers, bound in matched pairs, record some 41,000 entries and are themselves frequently cited as an example of the difficulty, since each register is a duplicate of the other and neither is the original.

The Bureau's work on Floor 407 is assisted by the Seventeen Mirrors of Partial Reflection, a classified set of instruments that reflect only a designated portion of any object or scene. Sixteen of the seventeen are held on the floor; the seventeenth has been on loan to the Hall of Receding Perspectives since 1961 and is the subject of a standing note in the Bureau's ledger reading “return requested; not yet returned.”

The Bureau's founding instruction is preserved in its own chamber and is short enough to quote in full:

“Where two things present alike, neither shall be preferred until both have been asked.”

— Bureau of Apparent Duplication, Founding Instruction, clause 2

The dispute over the west chamber

The west chamber, which returns an image at a delay of some two seconds, was for a long period claimed by both the Bureau and the Reflector Guild. The Guild's position rested on the Concordance of Reflective Practice, Annex 6, which assigns all delayed-reflection surfaces to Guild maintenance. The Bureau's position rested on the Concordance of Administrative Appetite, Annex 2, which assigns all surfaces answering to a registered name to the registering office, and the west chamber had been registered.

The two Concordances have never been reconciled, and the Hall of Administrative Precedent has declined the question twice, on the ground that it is “a matter of surfaces.” The dispute was settled in practice rather than in principle: since 1974 the Guild has cleaned the glass and the Bureau has kept the key. A clerk of the Guild, Emeric Vaunt, whose grievance survives in the form of a memorandum of nine pages, complained that he had polished the same chamber for eleven years without once being permitted to enter it while the lamps were lit. Vaunt's memorandum is filed on the floor and is catalogued as Concerning the Difficulty of Working in the Dark.

Use by the Hall of Adjudication

The south annex of the Hall of Adjudication uses Floor 407 for hearings in which testimony must be given facing a reflective surface, a procedure introduced after the Hall of Inception found that witnesses gave materially different accounts of the same event depending on whether they could see themselves while speaking. The annex's robing room is the only chamber on the floor with a door that closes properly, and it is reserved.

Hearings of this kind are not common. The procedure is invoked where the Hall of Unsettled Arguments has certified that an account is “stable in itself but unstable before others,” a formula that appears in no Concordance and has never been challenged.

Scholarly disagreement

The principal scholarly dispute concerning Floor 407 is whether it is one hall or several. The Substantivist School of Floor 419: The Hall of Plenitude maintains that a hall is constituted by the unity of the space it encloses, and that Floor 407 therefore comprises eleven halls, of which none is “The Hall of Mirrors.” The opposing position, advanced in the Hall of Conditional Echoes and never formally published, holds that the floor is named for what it does rather than what it contains, and that a floor which reflects has a sufficient unity.

A third view, recorded only in the marginalia of the Hall of Whispering Margins and of uncertain authorship, notes that the plaque was cut before the radiating walls were built and that the question is therefore one of archaeology rather than of definition. The plaque has not been moved.

Inventory

The floor's standing inventory, last revised 1988, is short:

• Eleven chambers; one rotunda; one robing room with a closing door.
• Four courses of set glass, dispositions as above.
• Sixteen of the Seventeen Mirrors of Partial Reflection.
• One pair of registers, neither original.
• One plaque, unseen from the stair-head after dark.

The lamps on Floor 407 are lit at the sixth bell and extinguished at the ninth. Requests to extend the hours are made to the Bureau of Metrological Calibration and are usually granted.