Alloy Γ-9

Alloy Γ-9 is a non-reactive ternary alloy of established standing in the Tower, most widely known as the material from which the shelving of The Vault is constructed. It is grey-white, faintly lustrous when newly cast, and notable chiefly for what it does not do: it does not oxidise, it does not discolour in the presence of the materials it stores, and it does not, under any conditions recorded in the assay ledgers, enter into combination with a catalogued substance. It is distinguished in the Tower's registers from the closely related Alloy Ω-7, from the proprietary Alloy Ψ-7 used in Resonance Shelves, and from the meta-substantive containment alloys such as Alloy Omega7, which are specified for phenomena rather than for shelves.

Composition and assay

Alloy Γ-9 is specified in the Metallurgical Schedule of the Third Concordance as a ternary alloy, though the Schedule declines to name its three constituents in the body of the text, referring the reader to "the sealed assay, held at the desk of the Keeper of the Furnaces." That assay has been produced on request eleven times since the Schedule was promulgated; on each occasion the requesting clerk was permitted to read the document in the presence of the Keeper and to take no copy. The composite testimony of those eleven readings, assembled by Clerk Anselm Vey of the Registry of Assay in 917, agrees on two constituents and divides on the third, which several readers recall as a grey powder and several others as a flux.

What is not disputed is the alloy's behaviour. Samples taken from the Vault shelves during the Third Inventory of the Lower Stacks were tested against forty-one reactive agents and returned no reaction in every case. The assay report describes the results as "unremarkable, and uniformly so" — a phrase the Registry has since adopted as a technical term of approval.

The Vault shelving

The Vault occupies a floor whose number is variously given; the Concordance of Floor Numbers, Annex 6, lists it as 2,214 while the Vault's own door-plate reads 1,996. Its walls are lined with shelves of Alloy Γ-9, and the choice is generally credited to the Keeper of the Vault, Marisol Enne, who argued in a memorandum of 1,203 that "a shelf should outlast the thing it holds and say nothing about it afterward." The memorandum is preserved in the Annex of Minor Justifications and is the only document in the archive that attributes a motive to the selection.

The shelves have required resurfacing twice in eight centuries, both times for mechanical wear at the shelf lips rather than for any chemical failure. A maintenance note appended to the second resurfacing, in 1,880, records that the replacement sections were "matched to the original within the tolerance of the eye, which is the only tolerance that matters here."

Dispute: the status of the third constituent

Scholarly disagreement over Alloy Γ-9 centres on whether its three constituents are to be understood as metals at all. The Fifth Concordance, Annex 12, defines a ternary alloy as "a union of three metals," and on that definition the grey powder recalled by several readers of the sealed assay presents a difficulty. Librarian Otho Prine, writing in the Proceedings of the Concourse on Materials, proposed that the definition be read as "three substances, of which at least two are metals," noting that the second recension of Archival Alloy 7-B was accepted into the registers on precisely that reading.

"The question is not what the alloy contains but what it consents to contain. A shelf of Γ-9 holds what is placed upon it and nothing more; this is the whole of its character, and it is enough."

— Librarian Otho Prine, Proceedings of the Concourse on Materials, vol. 14

The Registry of Assay has not adopted Prine's reading. Its standing annotation on the alloy reads only: "non-reactive; constituents as sealed." Clerk Vey, in a private note preserved with his papers, observed that the annotation "settles the matter by declining to discuss it, which is the traditional method and has the advantage of requiring no further ink."

Comparison with related alloys

Confusion between Alloy Γ-9 and its neighbours is common and has produced at least one formal complaint. The Guild of Shelfwrights petitioned the Concordance on Nomenclature in 1,641 after a consignment of Alloy Ψ-7 was delivered in crates stencilled "Γ-9," on the grounds that the two alloys are visually similar and that a shelfwright "cannot be expected to assay by candlelight what the stencil asserts in daylight." The petition was upheld; stencils are now required to carry the full designation in letters no smaller than the width of a thumb.

Alloy Γ-9 differs from Alloy Omega7 in purpose rather than appearance. Omega7 is specified for the containment of meta-substantive and persistently non-local phenomena, and its use on ordinary shelving is prohibited by the Ninth Concordance, Clause 12, which states that "an alloy of that order shall not be spent on a thing that stays where it is put." Γ-9, being a shelf alloy, is spent on exactly such things and is considered well spent.

Inventory note

The following stock is held against future resurfacing, as recorded by the Office of the Vault Stores in the current ledger:

• Alloy Γ-9 bar stock, 212 bars, stencilled and sealed
• Alloy Γ-9 lip-plate, 38 plates
• Assay certificates, sealed, 4 (three of which are certified copies of the same certificate)
• One crate marked "Γ-9" whose contents were re-assayed in 1,902 and found to be Alloy Ψ-7; the crate has not been opened since, and the Stores are content to leave it so

No further assay of the alloy is scheduled. The Keeper of the Furnaces has ruled that the sealed document is to be produced on request "as often as the Concordance requires, and no more often than the shelves require," a formula that has satisfied every party except the petitioners, who continue to request it.