Not the sea, but the sound of the sea

What is poetry?
by Eleanor Farjeon

What is poetry? Who knows?
Not the rose, but the scent of the rose;
Not the sky, but the light of the sky;
Not the fly, but the gleam of the fly;
Not the sea, but the sound of the sea;
Not myself, but what makes me
See, hear, and feel something that prose
Cannot; and what is it, who knows?