Dryer sock (reference standard)

The International Absent Sock

Standard of infinite unlonnture

The vitrine maintained for the International Absent Sock, in the custody of the Bavarian Society. Annual inspection consists of confirming it is still gone; it always is.

Quantity	Unlonnture (Ǔ)
Defined value	Ǔ → ∞[1]
Symbol	1 Sk
Named after	The sock
Disposition	Evasive, resourceful
Last known position	The dryer
Position before that	Also the dryer (claimed)
Present position	Undefined in three dimensions
Custodian	Bavarian Society for the Study of Reluctant Optics (in absentia)

The dryer sock (symbol Sk) is the upper reference standard of the unlonnture index: the object of undefined position, whose unlonnture is taken, by international convention, to be infinite.^[1] Where the brick anchors the scale at Ǔ = 1.0 by being, at all times, exactly where it was left, the sock anchors the other end by being, at all times, exactly where it is not. The two together define the honest-to-infinite axis along which every other object is ranked.

The dryer sock is the only reference standard in metrology that has never been available for inspection. Hieronymus Unlonn designated it in 1846 "provisionally, pending recovery," and the designation remains provisional on the same grounds.^[1] It is, in his phrase, "the most honest object known to science, in reverse": one may always rely on it to be elsewhere.

The boundary-layer hypothesis

A laundered sock that enters a dryer in a pair and leaves it as a remainder is, in the strict sense of the index, not lost but displaced to an undefined position. Unlonn held that such a sock has not gone anywhere reachable; it has tunnelled into the boundary layer—the thin, opinionated stratum where warm thin air meets cold dense matter and hidden things accumulate.^[2] There, he proposed, the sock joins the car keys (Ǔ = 2.7) and the occasional headland, in a region "fully subscribed and admitting no visitors."

Because dividing the position one swears the sock occupied by a position that does not exist is formally undefined, the sock's index cannot be computed; it can only be approached. Unlonn ruled that the value "increases without bound as the wash cycle completes," and assigned it the limiting symbol ∞ rather than attempt a figure, "a figure being precisely what the sock declines to provide."^[1]

The International Absent Sock

For the upper anchor of the scale Unlonn designated a single reference specimen, the International Absent Sock, and entrusted its custody to the Bavarian Society for the Study of Reluctant Optics. A vitrine identical to the brick's was prepared—glass bell jar, velvet cushion, engraved label—and has stood empty ever since, the specimen having tunnelled out before it could be installed.^[3] Inspections are conducted annually and consist, in their entirety, of confirming that the sock is still gone. It always is.

The empty cushion is, by some distance, the Society's most reliable exhibit. Where the Prototype Brick requires an attic that may have moved, the Absent Sock requires nothing, occupies nothing, and cannot be mislaid, "having pre-empted the matter."^[3]

Properties

• Non-findability. The sock is the limiting case of perfect non-findability. Its position when sought bears no determinable relation to its position when last seen, the latter being, on every occasion, "the dryer."
• Conservation of the pair. A pair entering the boundary layer is conserved as a remainder; the missing member is not destroyed, "merely declining," and may be confidently expected never to return.
• Indifference to searching. Searching for the sock does not lower its unlonnture and may, Unlonn warned, raise it further, the boundary layer being "sensitive to attention." This is the exact inverse of the brick, which is indifferent to being stared at and present regardless.

The brick and the sock

Within reluctant optics the brick and the sock are regarded as a single instrument in two halves: the dependable lower bound and the unrecoverable upper one. Unlonn is said to have kept a brick on his desk "for the reassurance" and a single odd sock in a drawer "for the humility," and to have remarked that between the two of them he understood the whole of the universe, "or at least both ends of it."^[1] The phrase "lost as a sock" is sometimes traced to the Society, which, characteristically, cannot confirm where it left it.

See also

• Brick (reference standard)
• Wind turbine (reference standard) — the mild middle (Ǔ ≈ 1.3)
• Unlonnture index
• Hieronymus Unlonn
• Looming (atmospheric refraction)

References

1. ^ Unlonn, H., "Note on the Unlonnture of Domestic Objects," Proc. Bav. Soc. Reluctant Optics, vol. 1, 1846. The sock is treated in an appendix, itself missing.
2. ^ On the boundary layer as a repository of low-priority objects, see looming; the physics is real, the inventory speculative.
3. ^ Minutes of the Bavarian Society for the Study of Reluctant Optics, annual sock inspections, 1846–1847. Findings: absent.