Note 99 — Chapter XI · THE MEMORY OF FEELINGS.

Galton, in a note entitled “Arithmetic by Smell,” has described an arrangement by means of which he convinced himself that some arithmetical operations can be carried out by the help of olfactory images, as is done by means of visual and auditory representations. He trains himself to regard two whiffs of peppermint as equivalent to one of camphor, and three of peppermint with one of carbolic acid; he performs small additions, and, later on, operates with images only (visual and auditory representations being excluded). For details, see Psychological Review, January 1894.