Now, those hills appear to be blue; another day, they will incline more to grey; yet another day to violet or purple, or pinkish. In winter time, around New York, they would very likely take on a dry, whitish color. In fact, the color will vary according to the condition of the atmosphere and the quality of the light; depending upon how moist or dry, how warm or chill, the atmosphere may be, and whether the light is yellow or golden, grey or white, full or feeble, and so on. It is these constant variations of lighted atmosphere that give continually fresh interest to the beauty of nature. Nature never wearies us by being always the same. It is like a human face, whose expression is continually changing.