To begin with, it must be remembered that a picture is a representation on a plane surface of limited area of certain physical facts in the world around us, for abstract ideas cannot be expressed by painting. In all the works in the world the painter, if he has tried to express the unseen or the supernatural, has expressed the unnatural. If he paints a dragon, you find it is a distorted picture of some animal already existing; if he paints a deity, it is but a kind of man after all. No brain can conjure up and set down on paper a monster such as has never existed, or in which there are no parts homologous with some parts of a living or fossil creature. We defy any man to draw a devil, for example, that is totally unlike anything in existence. All so-called imaginative works fall then within the category of the real, for they are in certain parts real because they are all based on realities, even though they may be utterly false to the appearance of reality. By this we mean that an ideal dragon may be based on existing animals; his form may be a mixture of a Cobra, Saurian, and a reptile, as is often the case; so far it may be real, but then the way in which it is painted may be utterly false, for the natural effect of light and atmosphere on the dragon may and probably will be ignored, for there is no such animal to study from. The modern pre-Raphaelites are good examples of painters who painted in this way; they painted details, they imitated the local colour and texture of objects, but for all that their pictures are as false as false can be, for they neglected those subtleties of light and colour and atmosphere which pervade all nature, and which are as important as form. Children and savages make this same error, they imitate the local colour, not the true colour as modified by light, adjacent colour, and atmosphere. But what the most advanced thinkers of art in all ages have sought for is the rendering of the true impression of nature.