The two lines with the least variation are a perfectly straight line and a circle. A perfectly straight line has obviously no variety at all, while a circle, by curving at exactly the same ratio all along, has no variation of curvature, it is of all curves the one with the least possible variety. These two lines are, therefore, 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 138figure, 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 139other point; perhaps the maximum amount of variety that can be got in a symmetrical figure, preserving, as it does, its almost perfect continuity, for it approaches the circle in the even flow of its curvature. This is, roughly, the line of the contour of a face, and you may note how much painters who have excelled in grace have insisted on it in their portraits. Gainsborough and Vandyke are striking, instances.
Diagram VII.
EGG AND DART MOULDING FROM ONE OF THE CARYATIDES FROM THE ERECHTHEUM IN THE BRITISH MUSEUM
The line of a profile is often one of great beauty, only here the variety is apt to overbalance the unity or run of the line. The most beautiful profiles 140are usually those in which variety is subordinated to the unity of the contour. I fancy the Greeks felt this when they did away with the hollow above the nose, making the line of the forehead r............