GOETHE'S

ARISTOTLE. "A vivid and brilliant red appears when the weak rays of the sun are tempered by subdued and shadowy white,"—154. LEONARDO "The air which is between the sun and the earth at sun-rise or sun-set, always invests what is beyond it more than any other (higher) portion of the air: this is because it is whiter."¹¹¹ A bright object loses its whiteness in proportion to its distance from the eye much more when it is illuminated by the sun, for it partakes of the colour of the sun mingled with the colour (tempered by the mass) of the air interposed between the eye and the brightness.¹¹² ARISTOTLE. "If light is overspread with much obscurity, a red colour appears; if the light is brilliant and vivid, this red changes to a flame-colour."¹¹³—150, 160. LEONARDO. "This (the effect of transparent colours on various grounds) is evident in smoke, which is blue when seen against black, but when it is opposed to the (light) blue sky, it appears brownish and reddening."¹¹⁴ ARISTOTLE. "White surfaces as a ground for colours, have the effect of making the pigments¹¹⁵ appear in greater splendour."—594, 902. LEONARDO. "To exhibit colours in their beauty, the whitest ground should be prepared. I speak of colours that are (more or less) transparent."¹¹⁶ ARISTOTLE. "The air near us appears colourless; but when seen in depth, owing to its thinness it appears blue;¹¹⁷ for where the light is deficient (beyond it), the air is affected by the darkness and appears blue: in a very accumulated state, however, it appears, as is the case with water, quite white."—155, 158. LEONARDO. "The blue of the atmosphere is owing to the mass of illuminated air interposed between the darkness above and the earth. The air in itself has no colour, but assumes qualities according to the nature of the objects which are beyond it. The blue of the atmosphere will be the more intense in proportion to the degree of darkness beyond it:" elsewhere—"if the air had not darkness beyond it, it would be white."¹¹⁸ ARISTOTLE. "We see no colour in its pure state, but every hue is variously intermingled with others: even when it is uninfluenced by other colours, the effect of light and shade modifies it in various ways, so that it undergoes alterations and appears unlike itself. Thus, bodies seen in shade or in light, in more pronounced or softer sun-shine, with their surfaces inclined this way or that, with every change exhibit a different colour." LEONARDO. "No substance will ever exhibit its own hue unless the light which illumines it is entirely similar in colour. It very rarely happens that the shadows of opaque bodies are really similar (in colour) to the illumined parts. The surface of every substance partakes of as many hues as are reflected from surrounding objects."¹¹⁹ Aristotle. "So, again, with regard to the light of fire, of the moon, or of lamps, each has a different colour, which is variously combined with differently coloured objects." LEONARDO. "We can scarcely ever say that the surface of illumined bodies exhibits the real colour of those bodies. Take a white band and place it in the dark, and let it receive light by means of three apertures from the sun, from fire, and from the sky: the white band will be tricoloured."¹²⁰ ARISTOTLE. "When the light falls on any object and assumes (for example) a red or green tint, it is again reflected on other substances, thus undergoing a new change. But this effect, though it really takes place, is not appreciable by the eye: though the light thus reflected to the eye is composed of a variety of colours, the principal of these only are distinguishable." LEONARDO. "No colour reflected on the surface of another colour, tinges that surface with its own colour (merely), but will be mixed with various other reflections impinging on the same surface:" but such effects, he observes elsewhere, "are scarcely, if at all, distinguishable in a very diffused light."¹²¹ ARISTOTLE. "Thus, all combinations of colours are owing to three causes: the light, the medium through which the light appears, such as water or air, and lastly the local colour from which the light happens to be reflected." LEONARDO. "All illumined objects partake of the colour of the light they receive. "Every opaque surface partakes of the colour of the intervening transparent medium, according to the density of such medium and the distance between the eye and the object. "The medium is of two kinds; either it has a surface, like water, &c., or it is without a common surface, like the air."¹²²