cylindrical canvas and viewed from
the centre thereof, where a fresh point of sight is required at every
twelve or sixteen feet.

Without a true knowledge of perspective, none of these things can be
done. The artist should study them in the great compositions of the
masters, by analysing their pictures and seeing how and for what reasons
they applied their knowledge. Rubens put low horizons to most of his
large figure-subjects, as in 'The Descent from the Cross', which not
only gave grandeur to his designs, but, seeing they were to be placed
above the eye, gave a more natural appearance to his figures. The
Venetians often put the horizon almost on a level with the base of the
picture or edge of the frame, and sometimes even below it; as in 'The
Family of Darius at the Feet of Alexander', by Paul Veronese, and 'The
Origin of the "Via Lactea"', by Tintoretto, both in our National
Gallery. But in order to do all these things, the artist in designing
his work must have the knowledge of perspective at his fingers' ends,
and only the details, which are often tedious, should he leave to an
assistant to work out for him.

We must remember that the line of the horizon should be as nearly as
possible on a level with the eye, as it is in nature; and yet one of the
commonest mistakes in our exhibitions is the bad placing of this line.
We see dozens of examples of it, where in full-length portraits and
other large pictures intended to be seen from below, the horizon is
placed high up in the canvas instead of low down; the consequence is
that compositions so treated not only lose in grandeur and truth, but
appear to be toppling over, or give the impression of smallness rather
than bigness. Indeed, they look like small pictures enlarged, which is a
very different thing from a large design. So that, in order to see them
properly, we should mount a ladder to get upon a level with their
horizon line (see Fig. 66, double-page illustration).

We have here spoken in a general way of the importance of this study to
painters, but we shall see that it is of almost equal importance to the
sculptor and the architect.

A sculptor student at the Academy, who was making his drawings rather
carelessly, asked me of what use perspective was to a sculptor. 'In the
first place,' I said, 'to reason out apparently difficult problems, and
to find how easy they become, will improve your mind; and in the second,
if you have to do monumental work, it wil