general law of the harmony of the eye will be this: That the corresponding colours in the Table hereafter mentioned will be in harmony with one another."
"In fact, if the organ of vision, after having been fixed on an orange colour, directs itself spontaneously, and uninfluenced by any external impulse, towards the indigo, or vice versâ; or if in nature a violet-coloured hyacinth is placed beside a jonquil, and the optic axis is turned from the one flower upon the other, the centre of the retina passes over that succession of colours which is demanded by the nature of the organ and cannot be felt but with pleasure and satisfaction. These two colours harmonize, because the one leads to the other; and, for the contrary reason, if the eye has to pass from one colour to another, not corresponding with it in the table, it will necessarily have to make a disagreeable effort, because it will find itself in a position not in harmony with its former state. If the ocular harpsichord of Caslet were possible, the modulation of the colours would be executed on it according to the principle just laid down[1]."
I will not deny that the aptitude of the retina to cause an imaginary to arise from a real colour is of some account in the effect produced by colour. I am even inclined to believe that colours attentively observed are, by this tendency of the organ, associated with a sentiment and endowed with an expression which they could not otherwise possess. This however would be a species of melody and not of harmony.
Harmony is an instantaneous effect produced on the mind by several colours united altogether independent of the development of imaginary colours. Before this development can take place, the eye must be fixed for some time on a real colour; nor is this all, it is also necessary that the real colour should be seen in a bright light. Now, when I have one or two colours before my eyes, I can judge of their harmony without being obliged to look at them for a long time or requiring a very bright light. If I observe them for a single instant, my judgement is already pronounced, with the same promptitude with which the ear decides when it is affected by the harmony of sounds. Suppose for a moment that real sounds had their corresponding imaginary sounds, and the latter were determined when the ear had been for some time affected by a single quality of sounds suitably sustained. In the first place, these imaginary sounds could make no impression except in the particular case in which the notes are sustained for some time; but if we suppose that they accompanied the real sound necessarily and in every circumstance, they would not be in harmony with it; they would be perceived an instant after it, and would produce melody.
When a particular colour is ill-assorted with another, the eye is offended, as the ear is hurt by a discord. If we pass from one of these
- ↑ Venturi, Recherche Physique sur les Couleurs, for which the prize of the Italian Society was awarded. Modena, 1802.
