If it is a landscape you are studying, you will find, possibly, that the sky, which from a distance seems to be grey, is really composed of streaks of blue and pink and grey. It is, in the first place, by these streaks of the brush, and, secondly, by the infusion of several colors, that the artist has succeeded in making his sky have the appearance of atmosphere, extending far and far back. Then, if you examine the trees, you may possibly find the strokes short and stubby, so as to bring out the character of the foliage; while, what from a distance gave the impression of being simply green, is also found on closer inspection to contain many spots of other colors. It is in this way that the action of light upon the foliage has been suggested; so that the trees from a distance do not seem hard and heavy but penetrated with light and atmosphere.