1891.] Visibility of the different Rays of the Spectrum. 

 Table I continued. 



513 



tending to the blue will be seen, but if the eye be turned towards the 

 red end or violet, the green is seen outside the central spot and the 

 colour reappears. I propose to return to this in a fuller discussion 

 of the subject. 



The first table shows the actual observations in the spectrum. 



