The disquisition is continued under the headings: How easily Color arises; How energetic Color may be; Heightening to red; Completeness of Manifold Phenomena; Agreement of Complete Phenomena; How easily Color disappears; How durable Color remains; Relation to Philosophy; Relation to Mathematics; Relation to Physiology and Pathology; Relation to Natural History; Relation to General Physics; Relation to Tones. Then follows a series of sections dealing with the primary colors and their mixtures. These sections relate less to science than to art. The writer treats, among other things, of—Æsthetic Effects; Fear of the Theoretical; Grounds and Pigments; Allegorical, Symbolical, and Mystical Use of Colors. The headings alone indicate the enormous industry of the poet; showing at the same time an absence of that scientific definition which he stigmatized as "pedantry" in the case of Newton.
In connection with this subject, Goethe charged himself with all kinds of kindred knowledge. He refers to ocular spectra, quoting Boyle, Buffon, and Darwin; to the paralysis of the eye by light; to its extreme sensitiveness when it awakes in the morning; to irradiation—quoting Tycho Brahe on the comparative apparent size of the dark and the illuminated moon. He dwells upon the persistence of impressions upon the retina, and quotes various instances of abnormal duration. He possessed a full and exact knowledge of the phenomena of subjective colors, and described various modes of producing them. He copiously illustrates the production by red of subjective green, and by green of subjective red. Blue produces subjective yellow, and yellow subjective blue. He experimented upon shadows, colored in contrast to surrounding light. The contrasting subjective colors he calls "geforderte Farben," colors "demanded" by the eye. Goethe gives the following striking illustration of these subjective effects: "I once," he said, "entered an inn toward evening, when a well-built maiden, with dazzlingly white face, black hair, and scarlet bodice and skirt came toward me. I looked at her sharply in the twilight, and when she moved away, saw upon the white wall opposite a black face with a bright halo round it, while the clothing of the perfectly distinct figure appeared of a beautiful sea-green." With the instinct of the poet, Goethe discerned in these antitheses an image of the general method of nature. Every action, he says, implies an opposite. Inhalation precedes expiration, and each systole has its corresponding diastole. Such is the eternal formula of life. Under the figure of systole and diastole the rhythm of nature is represented in other portions of the work.
Goethe handled the prism with great skill, and his experiments with it are numberless. He places white rectangles on a black ground, black rectangles on a white ground, and shifts their apparent positions by prismatic refraction. He makes similar experiments with colored rectangles and disks. The shifted image is sometimes projected on a screen,
