EXPERIMENTS ON DOUBLE VISION. 2H 



produce only a single perception : others, that, as similar and in capacity 



impressions cannot be distinguished, we have but one per- ? fdlstin . gulsh ~ 

 r ° ' 1 ing similar per- 



ception, though there are two impressions. But it iseasy to ccptions. 



see how far these hypotheses are from affording a satisfactory These unsatis- 

 explanation of the phenomena : for it is evident, that, ac- 

 cording to the one, we can in no case distinguish similar 

 objects; and according to the other it would be impossible 

 for us to be sensible of the compound perceptions established 

 by our experiments. 



The explanation of the physiologists who tell us, as well as that 

 that perception, being received in a simple subject, perception is 



f , ,, . ° • i i, i sim ple, because 



cannot be otherwise than simple, by no means elu- received in a 



cidates the question. Whatever opinion may be enter- sim ple subject. 



tained of the cause of our sensations, it is certain, that Faculty of com- 



we have within us a power that tends to individualize, man^imulta- 6 



to identify with our being, the different sensations we expe-neous sensati- 



rience at the same time. Thus in a piece of music we do ons ' 



not distinguish the sound of any one instrument in parti- as of sound, 



cular, or the effect of any of the parts that compose it : 



we receive only a simple perception, resulting from these 



manifold and simultaneous impressions. Thus two dishes, in and of taste. 



which the refinement of luxury has combined substances 



of the most heterogeneous nature, occasion only a mixed 



taste, without our being able to distinguish any of those 



of which it is compounded. But desirous of obtaining a 



more accurate knowledge of this faculty of identifying 



and combining simultaneous heterogeneal sensations, I at- Experiments of 



tempted to make experiments on the smell and taste analo- thl ^ kind .°" th 1 t 

 r ^ < taste and smell 



gous to those on the sight, and this by means of hete- scarcely practi- 

 rogenous flavours and odours of equal solubility and 

 volatility. , 



As I was unable to preserve the action of heterogenous Experiments 

 agents on these senses sufficiently distinct, to obtain satis- on tne bearing, 

 factory results, I attempted analogous experiments on the 

 sense of hearing, which, as it consists of a double organ 

 like that of sight, was better adapted to my experiments. 

 I took two leaden speaking trumpets, covered exteriorly Apparatus, 

 with wet cloths, and introduced their extremities, wrapped 

 round with tow, one into each ear. These were employed 

 tp isolate the sounds of two monocords, which I intro- 

 duced 

 1 



