Marble of Perpetual Sighing

The Marble of Perpetual Sighing is a metamorphic stone of the Tower's middle strata, quarried principally from the seams beneath Floor 9,140 and worked into acoustic surfaces on some four hundred recorded floors. It is distinguished from the several other resonant marbles of the archive — Lament Marble, Ignorance Marble, Susurrus Marble, and Prospero Marble — by a single property set out in the quarry returns of the Survey of Resonant Beds: the Marble of Perpetual Sighing does not sound when struck. It sounds continuously, and has done so since the moment it was cut.

The sigh produced is not an echo, an aftertone, or a resonance induced by air movement. Blocks recovered from sealed voids, wrapped in felt and carried to floors with no known acoustic connection, continue to exhale at a steady pitch measured at 43 cycles per minute — slightly slower than a resting breath. The Bureau of Unremitting Stone has maintained since 6,772 that the sound is not emitted by the marble at all but is the marble's ambient condition, and that striking it merely draws attention to what was already there.

Extraction and the Quiet Quotas

The working face beneath Floor 9,140 is administered under the Quiet Quota Ordinances, which fix the permissible volume of extracted noisy stone per season. The Ordinances were drafted for Lament Marble and were extended to the Marble of Perpetual Sighing by simple substitution of the noun, a procedure the Second Concordance had expressly forbidden nineteen years earlier and which no one has since challenged in writing.

Practical difficulties arise at the saw. Quarry crews are rotated at intervals of six hours; the Guild of Deferential Masons records that crews working longer shifts develop what its returns call "an answering habit," in which the worker unconsciously times their own breathing to the stone's. The Guild treats this as an industrial injury and pays a compensatory sum of eleven crowns per season. The stone is not required to reciprocate.

Extraction is prohibited between the hours of the Long Stillness, a prohibition of unknown origin that the Bureau of Unremitting Stone has twice attempted to rescind and twice withdrawn before second reading.

Dispute over classification

The principal scholarly disagreement concerns whether the Marble of Perpetual Sighing is a variety of Lament Marble or a distinct bed. The Fourth Concordance, Annex 9, holds that the two are the same stone under different working conditions: that lament-frequency tone, once established, cannot be extinguished, and that the "perpetual" designation is merely a Lament Marble that has been left to itself long enough.

The Seventh Concordance contradicts this directly at Clause 112, which states that Lament Marble generates acoustic phenomena when addressed, whereas the Marble of Perpetual Sighing addresses the reader. Clause 113 goes further: "A stone that speaks first has not been spoken to, and is not to be catalogued with those that wait."

"The distinction is one of initiative, and initiative is a property of the stone, not of the surveyor."

— Seventh Concordance, Clause 113

The Office of Lithic Reconciliation has sat on the question since 7,109. Its interim ruling permits either classification provided the surveyor notes which Concordance is being applied, a compromise that has produced two parallel catalogues and a generation of surveyors who classify by temperament rather than by test.

Use in construction

The stone's most extensive installation remains the Sighing Atrium, whose substructure contains significant architectural deposits of the bed and whose panels were dressed from the Floor 9,140 seam over a period of thirty-one years. The relationship between the Atrium's acoustic character and the stone's own continuous sigh was examined at length in Re: The Sighing Stair, which concluded that the two phenomena, though coincident in place, are separable in law, and that the Atrium's reclassification did not extend to its fabric. Appendix B of the same ruling remains the fullest account of the seam's behaviour under load.

Smaller works include the Hall of Attrition, the north stair of the Assize of Measured Grief, and the boundary wall of the Sighing Vaults, where the stone is set at intervals and its sound is largely masked by the building's other arrangements. The Ordo of the Sighing Pen has used dressed blocks of the marble in the construction of the resonance chambers through which its Empathetic Indexes are calibrated, though the Ordo has never confirmed which seam supplied them.

Known incidents

In the winter of 8,044 a consignment of forty blocks bound for the Hall of Attrition was delayed eleven days at the junction of Floors 6,208 and 6,209 following a dispute over wayleave. On arrival the blocks were found to have fallen out of unison with one another, each sighing at its own rate. The Guild of Deferential Masons re-pitched them by a procedure it declines to describe in writing. Two blocks did not recover and were returned to the quarry face, where they are said to have resumed the common rate within a day.

A lesser incident, recorded in the day-book of the clerk Adelina Voss, concerns a single block installed in a reading room on Floor 11,377 and removed after nine weeks at the request of the readers. Voss's entry for the removal is five words long: "It was agreed by all."

Handling and prohibition

Blocks are wrapped in undyed felt and carried, never dragged, between floors. Dragging is permitted only downward and only on floors where no one is resident. The stone may not be installed in any room used for the swearing of oaths, nor in any room where a Concordance is read aloud; both prohibitions are ancient, and the Bureau of Unremitting Stone enforces them without recorded exception, though it has never stated its reasoning.