Top notes provide the first scent impression of a fragrance once it has been applied to the skin. They are usually lighter, more volatile aromas that evaporate readily. Their scent normally lingers for between five minutes and half an hour.
Middle notes, sometimes referred to as “heart notes”, make up the body of the blend. They may be evident from the start, but will usually take ten minutes to half an hour to fully develop on the skin. These are the notes that classify the fragrance family – green, floral, aldehydic, chypre, oriental, fougère or tobacco/leather.
Base notes are those with the greatest molecular weight. They last the longest, and are important as fixatives – they help slow down the evaporation rates of the lighter notes, giving the fragrance holding power. Common base notes include oakmoss, patchouli, woods, musk and vanilla.
Seems to me that this is both an interesting and a helpful way to look at the structure of a poem. There are poems with top notes, middle notes and base notes, as above.
I don’t think I’ve written any of them, though.