great predilection for vivid colours; that animals are excited to rage by certain colours; that people of refinement avoid vivid colours in their dress and the objects that are about them, and seem inclined to banish them altogether from their presence.—Note I.
PART II.
PHYSICAL COLOURS.
136.
We give this designation to colours which are produced by certain material mediums: these mediums, however, have no colour themselves, and may be either transparent, semi-transparent yet transmitting light, or altogether opaque. The colours in question are thus produced in the eye through such external given causes, or are merely reflected to the eye when by whatever means they are already produced without us. Although we thus ascribe to them a certain objective character, their distinctive quality still consists in their being transient, and not to be arrested.
137.
They are called by former investigators colores apparentes, fluxi, fugitivi, phantastici, falsi, variantes. They are also called speciosi and emphatici, on account of their striking splendour. They are immediately connected with the physiological colours, and appear to have but little more reality: for, while in the production of the physiological colours the eye itself was chiefly efficient, and we could only perceive the phenomena thus evoked within ourselves, but not without us, we have now to consider the fact that colours are produced in the eye by means of colourless objects; that we thus too have a colourless surface before us which is acted upon as the retina itself is, and that we can perceive the appearance produced upon it without us. In