e point of sight, as in Fig. 12,
the square looks unnatural and distorted. This, I may note, is a common
fault with photographs taken with a wide-angle lens, which throws
everything out of proportion, and will make the east end of a church or
a cathedral appear higher than the steeple or tower; but as soon as we
make our line of distance sufficiently long, as at Fig. 13, objects take
their right proportions and no distortion is noticeable.

[Illustration: Fig. 11.]

[Illustration: Fig. 12.]

[Illustration: Fig. 13.]

In some books on perspective we are told to make the angle of vision
60 deg, so that the distance _SD_ (Fig. 14) is to be rather less than the
length or height of the picture, as at _A_. The French recommend an
angle of 28 deg, and to make the distance about double the length of the
picture, as at _B_ (Fig. 15), which is far more agreeable. For we must
remember that the distance-point is not only the point from which we are
supposed to make our tracing on the vertical transparent plane, or a
point transferred to the horizon to make our measurements by, but it is
also the point in front of the canvas that we view the picture from,
called the station-point. It is ridiculous, then, to have it so close
that we must almost touch the canvas with our noses before we can see
its perspective properly.

[Illustration: Fig. 14.]

Now a picture should look right from whatever distance we view it, even
across the room or gallery, and of course in decorative work and in
scene-painting a long distance is necessary.

[Illustration: Fig. 15.]

We need not, however, tie ourselves down to any hard and fast rule, but
should choose our distance according to the impression of space we wish
to convey: if we have to represent a domestic scene in a small room, as
in many Dutch pictures, we must not make our distance-point too far off,
as it would exaggerate the size of the room.

[Illustration: Fig. 16. Cattle. By Paul Potter.]

The height of the horizon is also an important consideration in the
composition of a picture, and so also is the position of the point of
sight, as we shall see farther on.

In landscape and cattle pictures a low horizon often gives space and
air, as in this sketch from a picture by Paul Potter--where the
horizontal-line is placed at one quarter the height of the canvas.
Indeed, a judicious use of the laws of perspective is a great aid to
composition, and no picture ever looks righ