In view of the purpose and content of drawing as here demonstrated, there is no other principle of judgment that is relevant. Yet we often hear drawing judged by criteria which are founded upon no such concrete base but upon certain vague abstractions; or, again, upon a literary or moral base which could be applicable only to symbolic art. It is said that this or that draughtsman excels in "beauty of line." Now in spite of the labours of many painters and theorists, it cannot reasonably be held that one purely abstract line or curve is more beautiful than another, for the simple reason that people have no common ground upon which to establish the nature of abstract beauty. It may be, however, that even as certain simple forms are more easily apprehended than complex ones, there is the same distinction with regard to lines. If then an artist of clean vision sees in an object of reality such clear characteristic lines, he draws them not for their abstract beauty, but merely because by them alone can he express his idea of the form before him. The early Greek vase painters, and all great artists of primitive periods, being attracted only by the silhouette, became very subtle to observe nature's outlines in their most intelligible character, and to this capacity is due their "beauty of line," and not to any preconceived notion of an abstract line of perfect beauty, and nowhere will "beauty of line" be found on Greek vases, or elsewhere, that is not informed by, and does not express, a fine conception of nature's contours. So too in later three-dimensional drawing there is no beauty of line which does not intelligibly express not only the directions and angles of the main contour, but the inner modelling, i.e. the relief of the figure. It is only a superficial judgment that would prefer one drawing to another, even if both may be equally good, because the line of one is neat and the other "tormented." Contour being _in nature_ an ideal line between one form and another, it is illogical to treat it or criticize it in a _drawing_ as an actual and specific thing, apart from the forms that make it and are made by it. If an artist drew a dragon with deliberate disregard for animal construction, his drawing would be silly, and only by a profound knowledge of the forms of nature could it be made to have beautiful lines. Truth to nature is always originality, and it is the only originality worth the name.