Again, when the petals forming a whorl coalesce, they must, of course, produce a more or less regular circle. If the points of the petals remain as projections, then we get a circle with vandyked edges, as in the lily of the valley; if they do not project, then we get a simple circular rim, as in the bindweed. All the lovely shapes of bell-blossoms are simply due to the natural coalescence of four, five, or six petals; and this coalescence is again due to an increased certainty of fertilisation secured for the plant by the better adaptation to insect visits. Similarly, we know that the colours of the corolla have been acquired as a means of rendering the flower conspicuous to the eyes of bees or butterflies; and the hues which so prove attractive to insects are of the same sort which arouse pleasurable stimulation in our own nerves. Thus the whole loveliness of flowers is in the last resort dependent upon all kinds of accidental causes--causes, that is to say, into which the deliberate design of the production of beautiful effects did not enter as a distinct factor. Those parts of nature which are of such a sort as to arouse in us certain feelings we call beautiful; and those parts which are of such a sort as to arouse in us the opposite feelings we call ugly. But the beauty and the ugliness are not parts of the things; they are merely human modes of regarding some among their attributes. Wherever in nature we find pure colour, symmetrical form, and intricate variety of pattern, we imagine to ourselves that nature designs the object to be beautiful. When we trace these peculiarities to their origin, however, we find that each of them owes its occurrence to some special fact in the history of the object; and we are forced to conclude that the notion of intentional design has been read into it by human analogies. All nature is beautiful, and most beautiful for those in whom the sense of beauty is most highly developed; but it is not beautiful at all except to those whose own eyes and emotions are fitted to perceive its beauty. XXII. _ON CORNISH CLIFFS._