OlfactionaryPiesse's Odophone — The Gamut of Odours
In 1855, perfumer G. W. Septimus Piesse proposed that scents relate to each other the way musical notes do — that a fragrance could be composed like a chord, and a bad blend was simply a "discord" of smells. It's the single most-cited metaphor in perfumery history: the reason the industry still talks about "notes," "accords," and "composition" instead of just "ingredients" and "mixtures." Below is his actual gamut, transcribed directly from the primary source (the 1891 5th edition, pp. 48–49) rather than a secondary summary — every scent he assigned to every note, across both the treble and bass registers.
"In the following gamut I have endeavoured to place the name of the odour in its position corresponding to its effect upon our olfactory sense... If a perfumer desires to make a bouquet from primitive odours, he must take such odours as chord together; the perfume will then be harmonious." — Piesse, The Art of Perfumery, 1891
Reading the gamut top to bottom moves from the sharpest, most volatile smells toward the deepest and heaviest — not a coincidence: Piesse was independently describing the same top-to-base volatility spectrum this site's Academy course covers in Chapter 3, four decades before anyone had a chemical explanation (vapor pressure) for why it worked. He proposed building a fragrance by picking scents that "chord together" — adjacent or harmonically related notes — the direct ancestor of what this site calls an accord today.
Read the full chapter in context: Piesse's Art of Perfumery (both the 1855 first edition and the 1891 5th edition are in the historic-texts library).