essential to the pictorial impression.

But what is the essential in a painting? What is it makes one want to
paint at all? Ah! Here we approach very debatable and shadowy ground,
and we can do little but ask questions, the answer to which will vary
with each individual temperament. What is it that these rays of light
striking our retina convey to our brain, and from our brain to whatever
is ourselves, in the seat of consciousness above this? What is this
mysterious correspondence set up between something within and something
without, that at times sends such a clamour of harmony through our whole
being? Why do certain combinations of sound in music and of form and
colour in art affect us so profoundly? What are the laws governing
harmony in the universe, and whence do they come? It is hardly trees and
sky, earth, or flesh and blood, #as such#, that interest the artist; but
rather that through these things in memorable moments he is permitted a
consciousness of deeper things, and impelled to seek utterance for what
is moving him. It is the record of these rare moments in which one
apprehends truth in things seen that the artist wishes to convey to
others. But these moments, these flashes of inspiration which are at the
inception of every vital picture, occur but seldom. What the painter has
to do is to fix them vividly in his memory, to snapshot them, as it
were, so that they may stand by him during the toilsome procedure of the
painting, and guide the work.

This initial inspiration, this initial flash in the mind, need not be
the result of a scene in nature, but may of course be purely the work
of the imagination; a composition, the sense of which flashes across the
mind. But in either case the difficulty is to preserve vividly the
sensation of this original artistic impulse. And in the case of its
having been derived from nature direct, as is so often the case in
modern art, the system of painting continually on the spot is apt to
lose touch with it very soon. For in the continual observation of
anything you have set your easel before day after day, comes a series of
impressions, more and more commonplace, as the eye becomes more and more
familiar with the details of the subject. And ere long the original
emotion that was the reason of the whole work is lost sight of, and one
of those pictures or drawings giving a catalogue of tired objects more
or less ingeniously arranged (that we all know so well) is the
result--