no counterpart in the other sense, — no succession of imaginary sounds resulting from those which had previously reached the tympanum.
In music there is a well-known and long-established distinction between harmony and melody: the former arises from a certain series of sounds produced all at the same time, the latter from the succession of certain sounds produced according to a certain rule. Can the science of colours lay claim to a similar distinction? I look at a fine painting, and am at once struck with the harmonious disposition of its beautiful colours. This is the first feeling excited, and it is excited in a moment. I afterwards examine and study the composition by looking attentively now at one point and then at another. The merit of the piece was at first confined to the beauty and harmony of the tints; now the same tints being observed with more attention awaken, or tend to awaken, the idea of the imaginary colours, and thus acquire an expression which was wanting to them when they were passed rapidly over. It has already been observed that the green-yellow arose from the violet, and that the latter colour had a tendency to produce a sensation of sadness on account of its involving a necessary transition from an acute to a grave tone. The lower colours of the spectrum (the red and the golden) have as their imaginary colours azure-green and indigo. In both these cases the passage is from the grave to the acute, and the two colours should, according to the law under consideration, excite a feeling of cheerfulness. The theoretical inference is confirmed by every one's experience.
This analogy between sounds and colours may, after all, be rather apparent than real. I thought myself bound nevertheless to mention it, with a view to its development, and on account of the new ideas which it might suggest.
Additional Note on the Law of Varying Colours.
In speaking of this law, I have remarked an analogy which presents itself in the central tints of the second ring. After having concluded my labours it occurred to me to examine this interval once more, and I noticed a fact which had escaped me in my first inquiries. Beginning with the perpendicular incidence, in order to pursue the examination through the other incidences, I observed the rings attentively. As my point of view I took the central part of the second ring, and there, at an angle between 70° and 80°, I perceived a new ring formed. This appearance was not accompanied by the disappearance of any of the other rings: it was really a new ring formed under this great inclination at the centre of the second, which was at first almost entirely white. I shall distinguish this ring from the others by the epithet intruded[1].
- ↑ It may not be useless, perhaps, to mention that my rings are inverse to those of Newton; his begin at the centre, mine at the circumference, where, from the nature of the electro-chemical process, the thinnest layers are deposited: the thickest layers are evidently those of the centre.
