§ 200. (2.) The divers forms in which an
FYom position of object may be presented to the eye in

a landscape will often vary the effect.
Sloping grounds and objects appear foreshortened.
Undulating grounds appear more extended than
plane surfaces. Strait roads or fences crossing
valleys obliquely appear curved. This different
aspect presented by the same object as to its form
and size is an element of aesthetic effect which
demands careful study of the artist in landscape.
§ 201. (3.) The laws of light itself as
From tiamre of ^j^^ medium of vision require careful

attention in landscape. The princi-
ples of what is called aerial perspective have here
a wide application. The effect of distance on the
apparent size and relative form of objects, and on



54^ LAWS 6]^ J^EAUTV.
their apparent relations to one another in position
and in magnitude ; the varying effect of dawning,
midday, and evening light, of haze and cloud, of
shade and coloring, all require study. For illustra-
tion, views to be taken from a southern outlook
need different treatment from those from a northern ;
those from an eastern outlook, a different treatment
from those from a western. The effect of long
vistas through rows of trees may be enhanced by
breaks, and also by a gradually deepening foliage.
