es 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]

Well, it was of the power to stimulate the tactile consciousness--of the
essential, as I have ventured to call it, in the art of painting--that
Giotto was supreme master. This is his everlasting claim to greatness,
and it is this which will make him a source of highest aesthetic delight
for a period at least as long as decipherable traces of his handiwork
remain on mouldering panel or crumbling wall. For great though he was as
a poet, enthralling as a story-teller, splendid and majestic as a
composer, he was in these qualities superior in degree only, to many of
the masters who painted in various parts of Europe during the thousand
years that intervened between the decline of antique, and th