The Etude magazine, February 1929, p. 86
Transposition By MARGARET GARDNER
TRANSPOSITION simply means a change of tonality. The pupil will find an apt comparison for this by going from one room to another and describing what he sees that is different in the two rooms. He will tell you first of all that there are different chairs, pictures and curtains, and that even the wallpaper is not the samewhich all means that there is simply a change in furnishings. Next he will point out that the wallsthat is, the fundamental structures of both roomsare the same.
Transposing is like going from one room to another. The sharps and flats in the new key are the furnishings. The melody and rythm are the walls.