The Artist's Repository, Or, Encyclopedia of the Fine Arts (Band 2): Perspective, Architecture (London, 1808)

iECT. III.] ON PERSPECTIVE.

107

PLATE XXXV.

No. T. Figure 1. To the foregoing example, this
adds the method of finding the fhadow on a plane
inclined to the horizon, but perpendicular to the
picture.

The firft part of the procefs, is exactly as the fore-
going; I the fpeclator's Eye; J its feat: R the lu-
minary ; S its feat; S T the declination of the rays:
procure the point II as before, by drawing from J to
the picture a line linking it beneath v, from whence
erect a perpendicular, and from I draw (parallel to
the original ray) I r: erect at C a vertical line, which,
cut by one perpendicular to it from r, gives D for the
feat of the fun on the vertical plane.

Now to procure the vanifhing points for the fha-
dows on the inclined plane Y; through C draw C V,
(correfponding to the direction of the plane Y) cut
by r D at V; which is the vanishing point for the
fhadows of horizontal objects on Y. The line VC
continued till it interfects rH, (as at v) gives v as
the vanifhing point for fhadows of vertical objects
on Y.

Of the fhadows in this example, pq tend to H;
being on the horizontal plane: k3 fhadow of g,
tends to D ; being on the vertical plane: o, fhadow
of e, tends to V; being horizontal on the inclined
plane: and z being vertical, its fhadow y on that
plane tends to v.

Figure 2. Shews the fyftematic lines, freed from
objects and fhadows, and in their proper bearings
as feen direct. The references are the fame.

Suppofing the foregoing figures fufEcient to ex-
plain the general principles of fhadows projected
either by a lamp, or by the fun, we proceed to no-
tice the application of thefe principles to illuminated
objects.

PLATE

i

v ,