Harold Speed

Unity of line is a bigger quality than variety, and as it requires a larger mental grasp, is more rarely met with. The bigger things in drawing and design come under its consideration, including, as it does, the relation of the parts to the whole. Its proper consideration would take us into the whole field of Composition, a subject needing far more consideration than it can be given in this book.

The masses that go to make up a picture have variety in their shape, their tone values, their edges, in texture or quality, and in gradation.

What has been said about unity of line applies obviously to the outlines bounding the masses, so that we need not say anything further on that subject. The particular quality of which something should be said, is the unity that is given to a picture by means of a well-arranged and rhythmically considered scheme of tone values.

There seems to be a strife between opposing forces at the basis of all things, a strife in which a perfect balance is never attained, or life would cease. The worlds are kept on their courses by such opposing forces, the perfect equilibrium never being found, and so the vitalising movement is kept up. States are held together on the same principle, no State seeming able to preserve a balance for long; new forces arise, the balance is upset, and the State totters until a new equilibrium has been found.