Spectrum and the Primary Colour Sensations. 75* 



Fig. 19. 



•40// 



•50 -60 



Wave Length. 



70 



red sensation corresponds to some hue between the beginning 

 of the red and the point of transition at X'660/a. Similarly, 

 the fundamental green sensation is excited by some portion 

 of the sneetrum lvinsr between the second and third transition 



