M8 A Syntonic Hypotliesis of Colour Vision. 



7. Summary and Conclusion. 



The hypothesis is here advanced that each element of the 

 retina may possess syntonic vibrators of frequencies corre- 

 sponding to those of red, green, and violet light respectively. 

 These responders are supposed to be of molecular, atomic, or 

 electronic nature somewhat like the resonators of Planck. 

 The adequacy of three such responders to yield the great 

 variety ot: effects corresponding to those of visual experience 

 is tested by an experimental arrangement. This consists of 

 a horizontal cord from which hang three light pendulums. 

 These are sympathetically stimulated by one or more heavy 

 pendulums hung from the same or an associated cord. The 

 light pendulums represent the vibrators supposed present in 

 the eye. The slight displacements of the cord from which 

 they hang represent the light incident upon the eye. The 

 heavy pendulums which produce these displacements are 

 like the luminous sources. 



In order that a vibration of any frequency throughout 

 the range corresponding to the visible spectrum should 

 appreciably stimulate these responders, their " resonance ' r 

 must not be too sharp, The responders must accordingly 

 have considerable damping. To account for the persistence 

 of vision and some sluggishness in its inception it is further 

 supposed that the responders in the eye do not act directly 

 on the nerves. On the contrary it is imagined that they 

 only start some physiological change which lasts about a 

 tenth of a second. And this change in its turn is supposed 

 t-> stimulate the nerves. 



The behaviours < f these three responders under various 

 conditions of stimulus are photographically recorded and 

 compared with the facts of colour vision. It is thus found 

 that on theso suppositions red and green would make yellow,. 

 blue and yellow would make a pinkish tint, and so on for 

 other facts of normal colour vision. 



The cases of colour-blindness would be met by the 

 supposition of the absence of " resonators " of certain 

 frequencies. 



No claim is made that the resonators postulated have 

 been proved to exist. The considerate ns here put forward 

 simply show that if the mechanisms postulated were present, 

 colour vision would be in the main as we now find it. 



Nottingham, 

 May 30, 1919. 



