Now here's something entirely fascinating.

In 1855, the perfumer Septimus Piesse wrote a book entitled The Art of Perfumery, in which he proposed the following theory: that 'there is, as it were, an octave of odours like an octave in music; certain odours coincide, like the keys of an instrument.' I read this in Not Even Wrong: Adventures in Autism, by Paul Collins, a touching and intriguing account of his own son's autism combined with studies of other autistic indivduals and phenomena through history, which I'd highly recommend. The book includes the scale printed out in musical notation, but I can't find it on the Net read Collins's book and you'll find it on p 127 ... however, if you go to page 26 on this link, you'll see what Piesse did: he arranged all the major scents along a treble and bass clef. The idea is that you can combine scents like musical notes: a harmonious chord smells delicious, a clashing one is revolting, just like chords can please or displease the ear. He called it an 'odophone'.

Isn't that fascinating?