REFRACTION
addition to this, to be conscious of all the twigs and blades of grass and other infinite details around about.
Now any interesting picture motive generally has a focus, or centre of interest on which the artist's eye rests with especial pleasure; and in view of the visual limitation just described it is evident that this portion will appear much more definite in outline than the outlying regions of the composition; which will become more and more blurred, as they recede, with the softened or lost edge everywhere. This is refraction; and as the eye sees it, so, without question, the hand should paint it.
But there are other motives—certain of Whistler's nocturnes, for instance—wherein the eye broods dreamily over the whole scene, not resting fixed upon any one given point of interest; and these should be painted precisely as
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