COLOUR-VISION AT DIFFERENT POINTS OF THE RETINA. 



colour of the hair or the iris of the individual, as to run through families 

 independent of outward complexion. 



The same difference is found between different colour-blind persons; so that 

 in the comparison of their vision with that of the normal eye, persons should 

 be selected for comparison who have the yellow spot of nearly the same intensity. 



In my own eye the part of the spectrum from A to E is seen decidedly 

 better by the central part of the retina than by the surrounding parts. Near /' 

 this is reversed, and the central part gives a sensation of about half the 

 intensity of the rest. Beyond G the central part is again the most sensitive, 

 and it is decidedly so near //. 



Before I conclude I wish to direct the attention of those who wish to 

 study colour to the exceedingly simple and beautiful series of experiments 

 described by Mr W. Benson in his works on colour. By looking through a prism 

 at the black and white diagrams in his book, any one can see more of the 

 true relations of colour than can be got from the most elaborately coloured 

 theoretical arrangements of tints. 



