required to produce the seven colours, and if we take the proportion of increase in the number of vibrations in a second required to produce the seven musical sounds of a diatonic scale, we shall find these proportions exactly the same. Some years ago, in England, I attended a lecture entitled "The Correlation of Light and Sound," and the lecturer produced on a screen a table of the ratio of wave-lengths in a second, producing the seven colours in spectrum, and the seven notes of a scale (of course, wave-lengths vary in number in inverse ratio to their velocity). I exhibit the table which I copied at the time.
You will here see the names of the seven colours in the spectrum placed over their relations, the seven notes of a scale, with the ratio of their wave-lengths, thus:—Note C, 100 = red; D, 89 = orange; E, 80 = yellow; F, 75 = green; G, 67—blue; A, 60 = violet; B, 53 = ultra-violet. Any diatonic scale would yield the same proportion of wave-lengths. Of course, the division in both is arbitrary, both sound and light being continuous from their lowest to their highest manifestations.
If we take the primary colours—red, yellow, and blue—in the above table we shall find that they occupy the same position in the spectrum as do the three notes forming the common chord in the scale—viz., the first, third, and fifth. Moreover, any two notes that sound discordant stand under colours that will not harmonize to the eye, and ditto vice versâ.
By the following illustrations on the screen I hope to make you realise the capability of colour to impress the brain in the same way as sound does the ear. I am aware that it is a very crude and inadequate attempt, but the means at my command are limited. In my mind's eye I can see a symphony of Beethoven rendered by electric flashes of coloured light, with all its grand concords and discords, producing the various emotions of peace or agitation, joy or sorrow, triumph or despair. We must remember that music began by simple melodies only, just as to-night I can give you such only in colour. What might not be done in the future?
Slide 1a: Colours in spectrum—red, orange, yellow, green, blue, violet, ultra-violet.
Small frames: Discord and concord.
| Discord | Concord |
| (having three secondary and one primary colour). |
(all primary colours). |
| Orange. d Green. f Blue. g Ultra-violet. b |
Red. c Yellow. e Blue. g Red. c |
Slide 1b: Four opening bars of Beethoven's Symphony in C minor, opening in E flat major. First four notes all pri-
