The natural elements of earth and air reappear constantly in his poems. The world, as he has written, will not end up in a book, as Mallarmé had claimed, since for du Bouchet the world has no end.
Du Bouchet's view is that the world is boundless and does not have an endpoint, unlike Mallarmé's belief that the world would be contained within a book.  The natural elements of earth and air are consistently present in his poetry.