COLOR VISION 



889 



the different purples, the blues and * violets, or only the greens and 

 grays. In the first instance, this would signify that he is red-blind, 

 and in the second that he is green-bhnd. If the red-bUnd is then asked 

 to match the red skein, he will pick out the greens, grays and browns, 

 possessing a luminosity less than that of the test color, while the greien- 

 bhnd will select the greens, grays and browns of greater luminosity. 



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