1488. In regard to light and shade, those parts of the groups which rise above the horizon, and are backed by the sky, are dark, and generally darker than such as are backed by the ground, or by other adjoining groups. The prominent parts of each group are lighter than the retiring parts or recesses among the spray and leaves. These prominent and retiring parts, in the near groups, are very numerous; in the distance they are lost in the general aerial shade of the group. It may be observed, as a general principle, that trees, from their rough surface, and consequently from their imperfect reflection of light, are always comparatively darker than water, buildings, or ground. In creating real landscape, they serve in some measure as shades, as the other materials mentioned serve as lights.
