We know that everything visible to the eye has color. When we think of a garden lawn, an impression of green comes into our mind. Green, an artist would say, is the local color of the lawn--the general hue which distinguishes it from the paths and flower beds. There may be dandelions spotted about the grass; indeed it is a lucky lawn that is not overrun with them; yet, notwithstanding the yellow patches, the local color of the lawn is green. And this is true, although here and there the grass may appear yellow in the warm sunshine, or, where the shadows of the trees lie, may have a bluish tinge; or again, in the distance may appear to be almost gray. You see then, that when we begin to talk about color, we do not think only of the general hue or local color, but also of the changes which take place in its appearance, according as it is subject to light and shadow or is seen near or further off.