Air (Aer)

The air glyph U+1F701 (🜁) is an inverted triangle, apex down, crossed by one horizontal bar in the upper third. Two oblique strokes meet at the lower vertex; a level stroke closes the base, enclosing a downward triangle. Scribes raise or lower the bar and sharpen or blunt the apex; fifteenth-century Latin hands keep it high and thin, while later process notes thicken it. Gessmann’s 1899 plates place Aer Spiritus among spiritus signs and record the plain barred triangle beside copies retaining a faint medial tick from a worn model. Newton’s transcripts use the same inverted, barred triangle for aer, opposed to the upright triangle of fire by orientation alone. Aqua is the unbarred downward triangle; terra crosses the lower half; aer keeps one high bar and straight sides, never a circle or Venus loop.

In the workshop, aer was not a bottled gas but the medium of the open furnace. Bellows, tuyères, and wind-furnaces drove a current across charcoal so that calcination and cupellation could proceed; assayers knew that a dead, enclosed fire left metals uncalcined and that a lively blast whitened litharge and parted noble metal from lead. Sublimation trains—aludel stacked on cucurbit, or a glass helm with recipient—carried volatile bodies upward on heated air and dropped them as flowers on cooler walls: sal ammoniac, sulfur, and orpiment were handled this way, the rising fraction called a spiritus. Mineral sources of such aerial salts included volcanic sal ammoniac and the soot of animal distillation, not a mine of nitrogen. Flame tests and, later, limewater parted fresh air from foul or fixed air, the breathable share now called dioxygen beside inert dinitrogen.

Aristotle placed aer between fire and water: hot and moist, source of breath, wind, and vapor that rises without becoming flame. It stands opposite cold, dry earth; its polarity is levity against weight and openness against occlusion. Jupiter, temperate and expansive, rules the airy triplicity in astrological physic; Mercury governs the laboratory spirit that rises, mediates, and will not stay fixed. Paracelsus kept the four elements but set the tria prima above them, so aer is both an external element and a vehicle of mercury when a body yields spirit. The barred downward triangle borrows water’s cup and marks moisture already turning volatile, neither plain aqua nor upright fire. Emblems show bellows, birds, and a figure pouring breath: the medium that carries vapors between heaven and the glass.

Greek theory enters the workshop through Aristotle and through Greco-Egyptian practice linked to Zosimos, where sublimation already lifts volatiles on heated air. Arabic treatises, especially the Jabirian corpus transmitted in Latin as Geber, describe flying spirits and the alembics and aludels that catch them. The Summa perfectionis and related Latin handbooks keep aer as the hot-moist corner of the elemental square. Paracelsus and his editors add a language of aerial niter and archaei that seventeenth-century chymists repeated even when they doubted the physics. Maier’s Atalanta fugiens (1618) joins emblem, epigram, and fugue so that air is shown as an operation, not only a name. Later symbol lists, of the kind Gessmann compiled, fix the barred inverted triangle as Aer or Spiritus: what the vessel admits or shuts out when matter is made to rise.

Sublimatio is the opus operation proper to aer. A body is heated so that its volatile part leaves the caput mortuum, travels through the neck or aludel, and concretes on a colder surface as flores. Repeated rise and fall—volatilize, then cool—continues until little gross earth remains and the spirit stands free of slag. Furnace draft brings heat; the hollow of the glass is the road the spirit travels. Sublimation commonly follows calcination and precedes fixation or imbibition, which returns the volatile to an earth that can bear fire. Jupiter’s expanse and Mercury’s mobility are emblems of that ascent, not replacements for lute and lamp. A poor joint spills the spirit into the room; a sound one lets aer make an occult quality visible as a deposit.

Eighteenth-century pneumatic chemistry dismantled aer as a simple element. Black’s fixed air, Cavendish’s inflammable air, and the oxygen of Scheele, Priestley, and Lavoisier showed common air as a mixture, chiefly azote (nitrogen) and oxygen. The old split between air that feeds calcination and air that kills flame became a composition. Berzelius and his peers replaced pictorial signs with letter formulae, so N and O, not a barred triangle, named the gases. Unicode 6.0 (2010) placed Alchemical Symbols at U+1F700–U+1F77F and set U+1F701 as AIR, the inverted triangle with one bar. Principe reads that survival as a key to furnace practice, not as proof that earlier authors already possessed the chemistry of N2 and O2.