§ 1. We turn our eyes, therefore, as boldly and as quickly as may be, from these serene fields and skies of mediæval art, to the most characteristic examples of modern landscape. And, I believe, the first thing that will strike us, or that ought to strike us, is their cloudiness.

Out of perfect light and motionless air, we find ourselves on a sudden brought under sombre skies, and into drifting wind; and, with fickle sunbeams flashing in our face, or utterly drenched with sweep of rain, we are reduced to track the changes of the shadows on the grass, or watch the rents of twilight through angry cloud. And we find that whereas all the pleasure of the mediæval was in stability, definiteness, and luminousness, we are expected to rejoice in darkness, and triumph in mutability; to lay the foundation of happiness in things which momentarily change or fade; and to expect the utmost satisfaction and instruction from what it is impossible to arrest, and difficult to comprehend.

§ 2. We find, however, together with this general delight in breeze and darkness, much attention to the real form of clouds, and careful drawing of effects of mist; so that the appearance of objects, as seen through it, becomes a subject of science with us; and the faithful representation of that appearance is made of primal importance, under the name of aerial perspective.