The forms which are his (the artist's) materials, the symbols which are his language, must in themselves have beauty and an interest readily appreciable by those who do not understand the occult meaning. Unless they have this they cease to be art: they become hieroglyphs. Art is picture painting, not picture writing. While this is generally true, beauty in the lesser signs of the poet is of greater importance than in those of the painter, because a painting is looked upon direct as a whole, while a poem has to be comprehended in its parts before it can be properly considered as a whole. [a] Laocoon. [b] _Life of Goethe_, 2d edition. NOTE 64. PAGE 203 Although those of the fifteenth-century artists who treated landscape seriously did not thoroughly understand perspective, yet they were seldom at a loss in representing distance, that is, in the clear atmosphere which they invariably used. They were diffident in attempting distance with unbroken level country, and till quite the end of the century there is no instance where middle and far distance are shown together, even with the assistance of hilly ground. The almost invariable practice of the leading painters who made landscape a feature in their works, was to introduce water leading back from the foreground, so that breaks therein could be used to indicate distance. More or less numerous jutting forks of low lying land were thrown into the stream from either side, this plan being successfully adopted in Italy,[a] Flanders,[b] and Germany.[c] Early in the sixteenth century much improvement was made in the use of water for providing distance, and a few of the Venetian painters gave some consideration to aerial perspective, but the most perfect example of this perspective in the period is contained in an early work of Raphael.[d] In the background is a lake extending into a gradually deepening haze, and in this a boat is so skilfully placed as to increase considerably the apparent distance to the horizon. This picture is a distinct advance upon the Venetian distance work of the time.[e] Later on in the century an artist rarely introduced water into a view specially to assist in producing distance by means of boats, more advanced methods being adopted. Titian used sunlight effects with varying shadows,[f] or alternating clear and wooded ground.[g] These plans, and the use of water with the addition of trees and low hills,[h] constitute the chief devices to be found in the late sixteenth-century Italian pictures. Some of the sun effects rendered for distance purposes even before Titian's best time are quite effective, though formal.[i] [a] See Piero di Cosimo's Death of Procris, National Gallery, London, and Mars and Cupid, Berlin. [b] Van Eyck's Chancellor Rollin before the Virgin, and Bout's Adoration of the Magi. [c] Lucas Moser's Voyage of the Saints (1431), Tiefenbroun, Germany.