e points _xx_ where these lines cut the base _B_ raise
perpendiculars _xa'_, _xb'_. From _D_, _A_, and _B_ draw lines to the
luminary _L_. These lines or rays intersecting the verticals raised from
_xx_ at _a'b'_ will give the respective points of the shadow.

[Illustration: Fig. 281.]

The shadow of the eave of a roof can be obtained in the same way. Take
any point thereon, mark its trace on the ground, and then proceed as
above.

CLVIII

SHADOW ON A RETREATING WALL, SUN IN FRONT

Let _L_ be the luminary. Raise vertical _LF_. _F_ will be the vanishing
point of the shadows on the ground. Draw _Lf'_ parallel to _FS_. Drop
_Sf'_ from point of sight; _f'_ (so found) is the vanishing point of the
shadows on the wall. For shadow of roof draw _LE_ and _f'B_, giving us
_e_, the shadow of _E_. Join _Be_, &c., and so draw shadow of eave of
roof.

[Illustration: Fig. 282.]

For shadow of _K_ draw lines from luminary _L_ to meet those from _f'_
the foot, &c.

The shadow of _D_ over the door is found in a similar way to that of the
roof.

[Illustration: Fig. 283.]

Figure 283 shows how the shadow of the old man in the preceding drawing
is found.

CLIX

SHADOW OF AN ARCH, SUN IN FRONT

Having drawn the arch, divide it into a certain number of parts, say
five. From these divisions drop perpendiculars to base line. From
divisions on _AB_ draw lines to _F_ the foot, and from those on the
semicircle draw lines to _L_ the luminary. Their intersections will give
the points through which to draw the shadow of the arch.

[Illustration: Fig. 284.]

CLX

SHADOW IN A NICHE OR RECESS

In this figure a similar method to that just explained is adopted. Drop
perpendiculars from the divisions of the arch 1 2 3 to the base. From
the foot of each draw 1S, 2S, 3S to foot of luminary _S_, and
from the top of each, A 1 2 3 B, draw lines to _L_ as before. Where the
former intersect the curve on the floor of the niche raise verticals
to meet the latter at P 1 2 B, &c. These points will indicate about the
position of the shadow; but the niche being semicircular and domed at
the top the shadow gradually loses itself in a gradated and somewhat
serpentine half-tone.

[Illustration: Fig. 285.]

CLXI

SHADOW IN AN ARCHED DOORWAY

[Illustration: Fig. 286.]

This is so similar to the last figure in many respects that I need not
repeat a description of the manner in which it is done. And