The Bitter Sink

The Bitter Sink (Floor 307, designated Spiral 3, Aperture 12) is a descending basin of worked halite approximately forty metres across at its rim and of unmeasured depth, maintained by the Librarians as the Tower's principal retention facility for saline bitter. It is not the deepest floor in the negative spiral and is not, by any account, pleasant to visit. Its historical importance rests chiefly on a single fact of supply: the Bitter Sink was the primary source of the refined halite used in the Great Salting of ‘07, and every subsequent recension of the salting records has had to account for it.

Geology and Construction

The Sink occupies a natural solution cavity in the halite bed that underlies the negative spiral between Floors 302 and 311. Early surveyors of the Bureau of Coincidental Resonance recorded the cavity in Year 41 as "a wound in the salt that has learned to keep its own weather." The rim was dressed and enclosed during the second visitation of Ardon Vell, whose party's survey notes describe four concentric terraces, a copper gutter running the full circumference, and air perceptibly drier at the third terrace than at the first.

The basin descends without recorded bottom. Soundings have twice been attempted; the plumb lines were withdrawn after eleven and nineteen days respectively, and the returning line in the second attempt had acquired a grey bloom that the assayers' office declined to classify. All subsequent practice has been to measure the Sink by its rim, its draw, and its taste, in that order.

Bitter as a Catalogued Substance

The Sink retains what the Tower's assayers call bitter: a category of saline liquor distinguishable from ordinary brine by persistence. A cup of Sink liquor poured into a larger vessel of water does not dilute away; it remains, in the phrase of the assayers' guild, "a remembered bitterness," detectable for a period the guild has declined to state in years. The retention is what makes the floor useful. Bitterness drawn from the Sink for industrial purposes — chiefly the preparation of the halite for the Great Salting of ‘07 — is then sunk a second time, in smaller quantity, to keep the basin's reserves from being wholly drawn down.

The economy is delicate. Sink-keepers hold that the basin responds poorly to haste, and the Bitter Mandate Cycle has from its first year regulated the timing of the draw: no more than a seasonal allotment may be lifted, and the allotment is set by the keeper, not the assayers. The eleventh year of that cycle, Year 309, is recorded as the Year of the Withheld Margin, in part because the Sink's margin was withheld.

The Sink-Keepers

The floor is staffed by the Sink-keepers, a small office answering to the Librarians but effectively self-recruiting. The office's founding keeper was one Hessaline Marr, who held the post for thirty-one years and left behind a post-book of great precision and no instructions. Her sixth entry, dated to the winter of Year 52, records that the floor's lowest terrace "had been found dry and was found dry the following morning," after which the note adds: "nothing to be done."

The keepers' grievance is long-standing and is the reason the office appears in so many Concordances. Under Clause 14 of the Third Concordance, any floor whose facility is designated a source in a Council salting is entitled to a keeper's stipend drawn from the salting's own surplus. The Great Salting of '07 produced no surplus. The keepers have petitioned four times and been answered twice; the first answer is missing and the second is the basis of their current claim, which is that the Sink is owed the deficit in kind.

Disputed Classification as a Sink

The Sink's status is not settled. The Resonance Sink was defined by the Librarians, following the Kappa-Aperture Discrepancy, as a designated area calibrated to irreversibly absorb, attenuate, and nullify specific classes of energy, and several offices have argued that the Bitter Sink qualifies by analogy. Concordance 77 designates Floor 301 as a resonance sink for Floor 303; the keepers' petition of Year 118 sought the same designation for Floor 307 as a sink for "bitterness at large," and was refused on the ground that bitterness at large is not a class.

The refusal did not end the matter. Annex Γ of the Seventh Concordance cites the Sink alongside the Quiet Forge and the Quiet itself, calling all three "sinks of their respective terms," and the comparison is repeated in the margin notes of the Bureau of Coincidental Resonance's third recension. The question turns on whether retention and nullification are the same act. The Sink's defenders say that a remembered bitterness is a bitterness removed from elsewhere; the office of the Third Concordance answers that a thing removed from elsewhere still exists, and the Sink is therefore a warehouse, not a sink.

"The Bitter Sink holds. It has never been shown to destroy, and a holding is a debt."

— Third Concordance, Annex 9, marginaliæ

Regulated Access

Visits to Floor 307 are permitted on written introduction from a Librarian and are conducted on the upper terraces only. The Sink's air, while dry at the rim, becomes sweet below the third terrace, and long residence has produced the condition the keepers call "the softening," in which the resident reports the basin as pleasant and is thereafter unreliable as a witness. Visitors may descend no further than the third terrace. Hats must be removed at the first.

The Sink remains in operation. Its bitter is drawn, its bitter is returned, its depth is unmeasured, and its ledgers, kept in a dry room off the rim, are the only reliable account of either.