The ordinary view is that the art of painting follows definite rules in attaining its results. This is, however, only true of the linear perspective, being as it is a wholly geometrical science, and even in this case rules must not obtrude themselves in their abstract stringency, if we are to preserve all that essentially contributes to our art. And, in the second place, we shall find that artistic drawing accommodates itself even less readily than perspective to universal rules, but least of all is this true of colouring. Sense of colour ought to be an artistic instinct or quality, should be as much a unique way of looking at and composing existing tones of colour, as it should be an essential aspect of creative power and invention. On account of this personal equation in the production of colour, the way, that is, the artist looks at and is active in the making of his world, the immense variety which we find in different modes of treating, it is no mere caprice and favourite mannerism of colouring, which is absent from the facts _in rerum natura_, but lies in the nature of the case. Goethe supplies us with an example of personal experience which, as confided in his "Dichtung und Wahrheit," illustrates what I mean: "As I returned to my cobbler's house [he had just visited the Dresden Gallery] once more to take lunch I could scarce trust the evidence of my eyes. I believed myself to see before me a picture of Van Ostade[307], so complete it was, that you might have hung it there and then in the Gallery. Composition of subject-matter, light, shadow, brown tone of the whole, all that is admirable in this artist's pictures I saw actually before me. It was the first time that I was aware, to such a high degree of the power which I subsequently exercised with intention, the power of seeing, that is, with the eyes of the particular artist, to whose works I had just happened to devote exceptional attention. This facility afforded me great enjoyment, but also increased the desire from time to time to persevere in the exercise of a talent which Nature seemed ungracious enough to disallow me[308]." This variety in the manner of colouring is exceptionally conspicuous in the painting of human flesh, quite apart from all modifications rendered necessary by the mode of lighting, age, sex, situation, and the like considerations. And for the rest, whether the subject depicted be daily life, outside or within the interior of private houses, taverns, churches, or other buildings, or it be that of Nature's landscape, with its wealth of objects and colour, which finds more or less accurate reflection in the personal essay of any particular painter, the result cannot fail to illustrate this varied play of form and colour effect[309], which will infallibly appear, due as it is to the manner in which each comprehends, reproduces, and creates his own work according to his own outlook, experience and imaginative powers.