198 



ROYAL SOClEl'Y OF CANADA 



It is noteworthy tliat tliese two depressions agree with the funda- 

 mental yellow and blue of the Hering thooi7 of colour vision, while the 

 blue is nearly that chosen by Helmholtz and by Konig and Diderici (viz: 

 À = .470 fx) as one of their fundanicTital colours. The wave lengths 

 of the maxima of the red and tthe gneen elevations also are the funda- 

 mentals of those colours wiiich have been selected by 'the last two writers. 



This curve w"ith its three elevations seems to support the view that 

 there arc but three fundamental colour sensations which are primarily 

 excited by certain lines of red, green and violet. 



TABLE 2. 



