"The varieties of colours are differently enumerated; some mention seven, others twelve, but without giving the complete list. From a consideration of the terminology both of the Greeks and Romans, it appears that they sometimes employed general for specific terms, and vice versâ.
"Their denominations of colours are not permanently and precisely defined, but mutable and fluctuating, for they are employed even with regard to similar colours both on the plus and minus side. Their yellow, on the one hand, inclines to red, on the other to blue; the blue is sometimes green, sometimes red; the red is at one time yellow, at another blue. Pure red (purpur) fluctuates between warm red and blue, sometimes inclining to scarlet, sometimes to violet.
"Thus the ancients not only seem to have looked upon colour as a mutable and fleeting quality, but appear to have had a presentiment of the (physical and chemical) effects of augmentation and re-action. In speaking of colours they make use of expressions which indicate this knowledge; they make yellow redden, because its augmentation tends to red; they make red become yellow, for it often returns thus to its origin.
"The hues thus specified undergo new modifications. The colours arrested at a given point are attenuated by a stronger light darkened by a shadow, nay, deepened and condensed in themselves. For the gradations which thus arise the name of the species only is often given, but the more generic terms are also employed. Every colour, of whatever kind, can, according to the same view, be multiplied into itself, condensed, enriched, and will in consequence appear more or less dark. The ancients called colour in this state," &c. Then follow the designations of general states of colour and those of specific hues.
Another essay on the notions of the ancients respecting the origin and nature of colour generally, shows how nearly Goethe himself has