THE QUARTERLY 



JOURNAL OF SCIENCE 



JANUAKY, 1870. 



I. LIGHT AND SOUND : 



AN EXAMINATION OF THEIR REPUTED ANALOGY. 



By W. F. Barrett, F.C.S., Natural Science Master at the 

 London International College, &c. 



Long before we knew anything of the origin either of sound, or 

 light, the existence of an analogy between these forces had been 

 the subject of speculation by some philosophers. But the idea of 

 such an analogy did not originate in philosophy; it was not con- 

 fined to a few ; it resulted in more than speculation. From the 

 earliest times we find among all nations a crude perception of a simi- 

 larity between sound and colour. This perception became rooted 

 in their languages. The same words, in many cases, were employed 

 to denote either light, or sound. A vivid impression received by 

 the eye was equivalent to a forcible shock received by the ear : thus, 

 the English " loud," the French " criard," the German " schreiend," 

 are identical expressions, relating to sound, also applied to glaring 

 colours. Faintness of vision and feebleness of voice were spoken of 

 as one. Our own words dim and dumb were probably cognate 

 terms in Anglo-Saxon. 



It is easy to trace this correspondence in language much farther, 

 but that is not our present business. Let us inquire if this wide- 

 spread mental analogy between sound and colour rests upon a 

 physical basis. Is it true that light and sound are alike, and if so 

 in what way are they alike ? How can the swift flash from a gun 

 be said to resemble the sluggish report that follows? Except 

 aesthetically, where is the likeness between a painting by Kaphael 

 and a theme by Beethoven ? 



At the outset let us remark that no attempt will be made to 

 show the identity of light and sound : it is their resemblance, their 

 parallelism, and not, of course, their oneness we wish to establish. 

 A parallelism that probably is metaphysical as well as physical ; so 

 that the estimation of beauty of colouring and harmony of sound 

 may, hereafter, be found to resolve themselves into mental actions 



VOL. VII. B 



