The colours which we see on objects are not qualities entirely strange to the eye; the organ is not thus merely habituated to the impression; no, it is always predisposed to produce colour of itself, and experiences a sensation of delight if something analogous to its own nature is offered to it from without; if its susceptibility is distinctly determined towards a given state.
From some of our earlier observations we can conclude, that general impressions produced by single colours cannot be changed, that they act specifically, and must produce definite, specific states in the living organ.
They likewise produce a corresponding influence on the mind. Experience teaches us that particular colours excite particular states of feeling. It is related of a witty Frenchman, "Il prétendoit que son ton de conversation avec Madame étoit changé depuis qu'elle avoit changé en cramoisi le meuble de son cabinet, qui étoit bleu."
In order to experience these influences completely, the eye should be entirely surrounded with one colour; we should be in a room of one colour, or look through a coloured glass. We are then identified with the hue, it attunes the eye and mind in mere unison with itself.
The colours on the plus side are yellow, red-yellow (orange), yellow-red (minium, cinnabar). The feelings they excite are quick, lively, aspiring.