erefore, two of the dullest,
and are seldom used in pictures except to enhance the beauty and variety
of others. And even then, subtle variations, some amount of play, is
introduced to relieve their baldness. But used in this way, vertical and
horizontal lines are of the utmost value in rectangular pictures,
uniting the composition to its bounding lines by their parallel
relationship with them. And further, as a contrast to the richness and
beauty of curves they are of great value, and are constantly used for
this purpose. The group of mouldings cutting against the head in a
portrait, or the lines of a column used to accentuate the curved forms
of a face or figure, are well-known instances; and the portrait painter
is always on the look out for an object in his background that will give
him such straight lines. You may notice, too, how the lines drawn across
a study in order to copy it (squaring it out, as it is called) improve
the look of a drawing, giving a greater beauty to the variety of the
curves by contrast with the variety lacking in straight lines.

The perfect curve of the circle should always be avoided in the drawing
of natural objects (even a full moon), and in vital drawings of any sort
some variety should always be looked for. Neither should the modelling
of the sphere ever occur in your work, the dullest of all curved
surfaces.

Although the curve of the perfect circle is dull from its lack of
variety, it is not without beauty, and this is due to its perfect unity.
It is of all curves the most perfect example of static unity. Without
the excitement of the slightest variation it goes on and on for ever.
This is, no doubt, the reason why it was early chosen as a symbol of
Eternity, and certainly no more perfect symbol could be found.

The circle seen in perspective assumes the more beautiful curve of the
ellipse, a curve having much variety; but as its four quarters are
alike, not so much as a symmetrical figure can have.

Perhaps the most beautiful symmetrically curved figure of all is the
so-called egg of the well-known moulding from such a temple as the
Erechtheum, called the egg and dart moulding. Here we have a perfect
balance between variety and unity. The curvature is varied to an
infinite degree, at no point is its curving at the same ratio as at any
other point; perhaps the maximum amount of variety that can be got in a
symmetrical figure, preserving, as it does, its almost perfect
continuity,