As the immediate purpose and content of drawing there remains the representation of form only. Drawing is, therefore, essentially the same activity as sculpture, and has no additional scope. "Pupils," says Donatello, "I give you the whole art of sculpture when I tell you to draw" (cited by Holroyd, _Michel Angelo_, p. 2 95), and the only practical teaching of drawing might be summed up by the inversion of the above. Now if everything in nature--men, mountains or clouds--were as flat targets, i.e. two-dimensional, drawing could be legitimately reduced to a mechanical process,--to trace their contours upon a glass screen or even photograph them would be all that would be required. Indeed, provided the size of the drawing, the local colour and the texture be the same as those of the original, a complete illusion would be the result, in fact the proper end of one's labours. But the presence of the third dimension in all objects causes light and shade, which in their turn bring about radical changes of the local colour, even in uniformly coloured objects. Now since drawing cannot suggest colour, local or atmospherical, any attempt to effect an illusion by a monochrome is at once defeated. If the end of drawing were to approach imitation or illusion as nearly as possible, how is it that a mere "sketch" by a master draughtsman can be for itself as valuable as his highly finished drawing? And surely a masterly outline drawing of a figure or landscape does not pretend to be an illusion. If then the draughtsman does not, and cannot hope to imitate nature, he is compelled to state only his ideas of it, ideas of three-dimensional form. For this reason only drawing must be treated as an art, and not as a mechanical act of getting an illusion. [Illustration: (From a Greek vase in the British Museum (E. 46). FIG. 1.] [Illustration: (From _Bulletino arch. Napol_. (1843, tom. 1, tav. 7). FIG. 2.] [Illustration: (From a drawing by Michelangelo (1854, 5, 13, i.), Print Room, British Museum). FIG. 3.]