76 



COLOUR VISION 



Fig. 29 shows the fields with 



red 



yellow 

 green 

 blue , 



670-5 fi/x 



589-2 „ 0-21 foot-candle 



530 „ 



460-3 „ 



-^vA 



180 



Fig. 29. The fields of vision for spectral colours witli low illumination (D light =0-21 foot- 

 candle at the screen). (Abney.) 



