8 2 o THE POPULAR SCIENCE MONTHLY. 



Wagner's gives the feeling of an atmosphere of light, changing 

 its colors in succession. 



Having established the mental nature of the impressions of 

 color, we come now to seek the cause of their apparition. "We 

 know pretty well what one means when he declares that a is 

 red ; but we have not explained how the idea or perception of a 

 sound can awaken the idea of a particular color. Our ideas have 

 generally a logical origin ; we are at least in the habit of believ- 

 ing this, and it often occurs, in analyzing our representations, 

 that we find the cause that brings them out and connects them. 

 If I hear a bell, and, without seeing it, conceive its roundish form, 

 its clapper, and its dark-green color, the connection of ideas is 

 understood to be natural, useful, and true; it is derived from 

 previous experiences. It is a piece of the outer world registered 

 in my mind. But these associations of colors with sounds are 

 factitious, have a purely individual character, and correspond 

 with nothing in the order of external facts. A sound is a sound, 

 and has nothing in common with a color. The human voice is 

 grave or sharp, and is not yellow or green. How has such an 

 association been created and developed in the face of good sense ? 

 It is evident that the act of establishing tenacious associations 

 between impressions that have nothing in common is the sign of 

 some intellectual form which is not everybody's. We are dis- 

 posed to attach some importance to the quality of the illusions 

 evoked. They are of a visual character, which seems to indicate 

 that there exists in colored audition an intense rush of visual 

 images and a tendency to think as well as to feel with them ; 

 in short, we suppose that those who have colored audition belong 

 to the category of visuals, or persons who, according to the classi- 

 fication of M. Charcot and many physiologists following him, have 

 visual memories. As the case of M. Inaudi enabled us to study 

 a high development of the auditive memory, another category in 

 this classification, colored audition, will perhaps permit us to study 

 visual ^memory. This is only a hypothesis ; for it is not abso- 

 lutely certain that colored audition always agrees with the type 

 of visual memory, and that there is a causal relation between the 

 two things, but we do not advance it without the support of good 

 reasons. 



First, we have the testimony of the subjects whom we have had 

 opportunities to question. We addressing them in a tone of in- 

 difference and without trying to dictate their responses, they have 

 remarked that colors and forms are the things they remember 

 most easily. A young woman to whom I sent my requests in writ- 

 ing to avoid the unconscious suggestions of accent, answered me, 

 "You ask me if I more easily recollect things seen or things 

 heard ; things seen. When I recollect a conversation, the gestures 



