The first of the great personalities in Florentine painting was Giotto. Although he affords no exception to the rule that the great Florentines exploited all the arts in the endeavour to express themselves, he, Giotto, renowned as architect and sculptor, reputed as wit and versifier, differed from most of his Tuscan successors in having peculiar aptitude for the essential in painting _as an art_. But before we can appreciate his real value, we must come to an agreement as to what in the art of figure-painting--the craft has its own altogether diverse laws--_is_ the essential; for figure-painting, we may say at once, was not only the one pre-occupation of Giotto, but the dominant interest of the entire Florentine school. [Page heading: IMAGINATION OF TOUCH] Psychology has ascertained that sight alone gives us no accurate sense of the third dimension. In our infancy, long before we are conscious of the process, the sense of touch, helped on by muscular sensations of movement, teaches us to appreciate depth, the third dimension, both in objects and in space. In the same unconscious years we learn to make of touch, of the third dimension, the test of reality. The child is still dimly aware of the intimate connection between touch and the third dimension. He cannot persuade himself of the unreality of Looking-Glass Land until he has touched the back of the mirror. Later, we entirely forget the connection, although it remains true, that every time our eyes recognise reality, we are, as a matter of fact, giving tactile values to retinal impressions. Now, painting is an art which aims at giving an abiding impression of artistic reality with only two dimensions. The painter must, therefore, do consciously what we all do unconsciously,--construct his third dimension. And he can accomplish his task only as we accomplish ours, by giving tactile values to retinal impressions. His first business, therefore, is to rouse the tactile sense, for I must have the illusion of being able to touch a figure, I must have the illusion of varying muscular sensations inside my palm and fingers corresponding to the various projections of this figure, before I shall take it for granted as real, and let it affect me lastingly. It follows that the essential in the art of painting--as distinguished from the art of colouring, I beg the reader to observe--is somehow to stimulate our consciousness of tactile values, so that the picture shall have at least as much power as the object represented, to appeal to our tactile imagination. [Page heading: GIOTTO]