16 Light and Sound. [Jan., 



the ratio given by the note A. The colours having now ceased, 

 the ideal position of B and the upper C in the spectrum are calculated 

 from the musical ratios. This coincidence, as unexpected as it is 

 perfect, is represented in the two upper figures on the Plate.* 



Had space permitted, we should have ventured to trace out to 

 some extent this common harmony of colour and sound. All we 

 can do is to point out a few suggestions that occur at once. 



Every one knows that the juxtaposition of two colours nearly 

 alike is bad, and it is well known that two adjacent notes of the 

 scale sounded together produce discord. Selecting and sounding 

 together two differeDt notes we may produce either discord or 

 harmony ; so with the juxtaposition of certain colours, either 

 pleasurable or painful effects are produced. Thus — the notes D and 

 E, together, are bad; so are orange and yellow when contrasted. 

 C and Gr harmonize perfectly, so do red and blue. C and F is an 

 excellent interval, so is the combination of red and green. Now, 

 on referring to the Plate, it will be seen that the foregoing notes 

 exactly underlie those very colours that we have named with them. 



But. further, it is possible to obtain a real optical expression of 

 the musical intervals.! By reflecting a beam of light from one 

 vibrating tuning fork to another placed at right angles, curves of 

 light are obtained, which vary according to the combination of forks 

 we select. The most perfect harmony, viz. two notes in unison, 

 gives the simplest curve — a circle. The next most harmonious 

 interval, an octave and its fundamental note, gives the figure of 8 ; 

 the next, the interval of a fifth, gives a more complete^ figure, and 

 so on. The complexity augmenting as the concordlessens. Some 

 of these curves are shown on the lower figure in the Plate. By 

 the side of each curve is put the musical notes from which it was 

 derived, and for the sake of comparison the colours which would 

 correspond to each interval are also brought down. It will be 

 seen that harmony runs throughout. 



A musical chord thus becomes both a representative picture, 

 and an acoustic painting, whilst the musical scale is literally a 

 rainbow of sound. It is hardly too much to say that we might 

 possibly translate into a musical melody a sunset, a flower, or a 

 painting by a Bubens or a Baphael.i 



But here let us check our imagination. We have throughout 

 the foregoing article endeavoured to avoid overstating the analogy. 

 Let us now be careful lest we become victims of the " idola tribus," 

 lest we strive to impose on nature a greater degree of simplicity 

 than her facts will justify. 



* There will be noticed over the spectrum on the Plate a scale of actual wave- 

 lengths, by which the remarkable but natural crowdiug together of the colours at 

 the red end is well seen. 



t First accomplished by M. Lissajous. 



% On this subject an able article by Mr. C. Seth Smith, recently appeared in 

 the * Builder.' 



