On the ledges, too, the lines are broken. In Rico's drawing, Fig.
11, all the outlines may be observed to have a break here and there.
This broken line is particularly effective in out-door subjects,
as it helps to suggest sunlit atmosphere as well as texture.

[Illustration: FIG. 17 DRAWING FROM A PHOTOGRAPH]

Architectural outlines, however, are not particularly subtle; it
is when we come to render anything with vague boundaries, such as
foliage or clouds for example, that the chief difficulties are
encountered. Foliage is an important element of landscape drawing
and deserves more than passing consideration. To make a successful
rendering of a tree in pen and ink the tree must be first well drawn
in pencil. It is absolutely impossible to obtain such a charming
effect of foliage as that shown in Mr. Pennell's sketch, Fig. 18,
without the most painstaking preparation in pencil. The success
of this result is not attributable merely to the difference in
textures, nor to the direction or character of the line; it is
first of all a matter of good drawing. The outline should be free
and subtle so as to suggest the edges of leafage, and the holes
near the edges should be accented, otherwise they will be lost
and the tree will look solid and characterless. Observe, in the
same drawing, how Mr. Pennell suggests the structure of the leafage
by the irregular outlines which he gives to the different series of
lines, and which he emphasizes by bringing the lines to an abrupt
stop. Observe also how the stronger texture of the tree in Fig. 19
is obtained by making the lines with greater abruptness. Compare
both of these Figures with the foreground trees by the same artist
in Fig. 20. The last is a brilliant example of foliage drawing
in pen and ink.