This effect of atmosphere is one of the things that we are now going to discuss. The other is that atmosphere penetrates everywhere. Suppose we begin with the second point. The atmosphere is in one respect like water; it is a fluid. It flows in and out and around about and fills the whole space that is not occupied by some other body. But have you thought what this means to an artist? Or at least to some artists; for we said that Copley’s pictures contained little or no suggestion of atmosphere. And the same may be said of a great many pictures by modern artists. They represent the form and color of things, but do not suggest that they are surrounded, or, as is often said, enveloped in atmosphere.

Why is this? Well! in the first place, as you remember, there are many artists who do not profess to represent nature. When they use nature as a model, it is for the purpose only of getting the forms of nature, and these they improve upon, as they will tell you, so as to make the forms in their picture “ideally perfect.” These “Academic” or “classic” painters[11] as I have already said, think of art as separate from nature. On the other hand, even among those who think of art as a means of interpreting nature, there are many artists who never put atmosphere into their pictures. Or, if they do, it is not nature’s atmosphere.

Then what sort of atmosphere is it? I call it a studio atmosphere, because it is manufactured in the studio. The artist, feeling the need of softening the hard outlines of his figures and of subduing any harshness of color, spreads over the picture thin layers of transparent, slightly colored varnish. Through these glazes, as they are called, the forms and colors are seen, somewhat as if you were looking at them through a piece of colored glass, and the effect is to merge or bathe them in a glow of atmosphere.

This was a usual practice with the great colorists of the Italian Renaissance. Correggio’s pictures, for example, are prized for their golden glow. It is one of the reasons of their beauty. But then, his idea was not to interpret nature. His subjects were drawn from the Bible, or the Christian religion, or Greek Mythology, and he treated them as his imagination suggested. He saw them through the glow of his own imagination, and surrounded them with a glow that seems to place them far away from actual things in a beautiful world of their own. Similarly, modern colorists, when they create pictures out of their own imagination, will suffuse them with an artificial atmosphere that helps to express the spirit of the scene. In fact, these atmospheric effects, produced by glazing, are beautiful and proper in their place. But their place is not in pictures that profess to be studies of nature. In these it is as wrong to suggest an unnatural atmosphere, as it is to leave out all suggestion of atmosphere whatsoever, which is, perhaps, the more usual fault.

Since the true rendering of atmosphere is a part of the true representation of light and color, you will not be surprised to learn that it appeared in the pictures of Velasquez and of the Dutchmen of the Seventeenth Century. We have already spoken of it in the case of Vermeer. It was from these artists that modern colorists, beginning about 1860, have learned to study the effects of atmosphere and light. They have carried the study even further than the older men. Indeed, the rendering of light and atmosphere has been the most distinct triumph of modern painting. There are two reasons for this.

One is, that with the advance of scientific studies and mechanical inventions, people have become more than ever interested in the every day facts of life; and the writers, painters, and sculptors, following with the stream, have studied more and more how to represent life and its surroundings, not as we may dream they should be, but as they are known to our actual experience. They have become ardent “realists” or “naturalists.” “Realists,” because they are occupied with what we are in the habit of calling the realities of life.[12] “Naturalists,” because they love nature and try to represent her actual appearances, as they are enveloped in and affected by light and atmosphere.

The second cause of the modern advance in rendering these qualities is again due to scientific discoveries. Scientific men have made a close study of light and color and the painters have profited by the results. Painting, in a measure, has joined hands with science.

However, now that we have seen why some artists do not put atmosphere into their pictures, and