_h
h h h_, and within that, guided by the intersections of the diagonals
therewith, we obtain the four points through which to draw square _K_.
To raise a solid figure on these squares we can make use of the
vanishing scales as shown on each side of the figure, thus obtaining the
upper square 1 2 3 4, then by means of the diagonal 1 3 and 2 4 and
verticals raised from each corner of square _K_ to meet them we obtain
the smaller upper square corresponding to _K_.

It might be said that all this can be done by using the two vanishing
points in the usual way. In the first place, if they were as far off as
required for this figure we could not get them into a page unless it
were three or four times the width of this one, and to use shorter
distances results in distortion, so that the real use of this system is
that we can make our figures look quite natural and with much less
trouble than by the other method.

[Illustration: Fig. 161.]

LXXXVI

SHOWING HOW A PEDESTAL CAN BE DRAWN BY THE NEW METHOD

This is a repetition of the previous problem, or rather the application
of it to architecture, although when there are many details it may be
more convenient to use vanishing points or the centrolinead.

[Illustration: Fig. 162.]

[Illustration: Fig. 163. Honfleur.]

LXXXVII

SCALE ON EACH SIDE OF THE PICTURE

As one of my objects in writing this book is to facilitate the working
of our perspective, partly for the comfort of the artist, and partly
that he may have no excuse for neglecting it, I will here show you how
you may, by a very simple means, secure the general correctness of your
perspective when sketching or painting out of doors.

Let us take this example from a sketch made at Honfleur (Fig. 163), and
in which my eye was my only guide, but it stands the test of the rule.
First of all note that line _HH_, drawn from one side of the picture to
the other, is the horizontal line; below that is a wall and a pavement
marked _aV_, also going from one side of the picture to the other, and
being lower down at _a_ than at _V_ it runs up as it were to meet the
horizon at some distant point. In order to form our scale I take first
the length of _Ha_, and measure it above and below the horizon, along
the side to our left as many times as required, in this case four or
five. I now take the length _HV_ on the right side of the picture and
measure it above and below the horizon, as in the other case