ACCIDENTS BY RAIL AND SEA. 



151 



but two fundamental colors, which, adhering strictly to the theory, are 

 green and violet (blue according to Maxwell). 



The curves distinctly show what aspect the various kinds of lights of 

 the spectrum must have for the chromatic sense such as the one we 

 have in view. We will give a short list of them, according to Helm- 

 holtz, by designating here the different kinds of lights, as we did before, 

 that is to say, by using terms borrowed from the impressions they pro- 

 duced on the normal chromatic sense ; the comparison will not be with- 

 out interest. 



" Spectral red, which feebly excites the perceptive organs of green, 

 and scarcely at all those of violet, must consequently appear to the red- 

 blind a ^saturated'' green of afeehle intensity, more 'saturated' than nor- 

 mal green, into which a sensible portion of the other primitive colors 

 enters. Feebly luminous red, which affects the perceptive organs of red 

 in a normal eye sufficiently, does not, on the other hand, sufiBciently 

 excite the perceptive organs of green in the red-blind, and it, therefore, 

 seems to them black. Spectral yelloiv seems to them a green ^ saturated^ 

 and intensely luminous, and as it constitutes the precisely saturated and 

 very intense shade of that color, it can be understood how the red-blind 

 select the name of that color, and call all those tints that are properly 

 speaking green, yellow. Green shows, as compared with the preceding 

 colors, a more sensible addition of the other primitive colors; it then 

 appears, consequently, like a more intense but whitish shade of the 

 same color as yellow and red. The greatest intensity of light in the 

 spectrum, according to Seebeck's observations, does not appear to the 

 red-blind to be in the yellow region, as it does to the normal eye, but 

 rather in that of the blue- green. In reality, if the excitation of the per- 

 ceptive organs of green, as it was necessary to assume, is strongest for 

 green, the maximum of the total excitation of the red-blind must bo 

 found slightly toward the blue side, because the excitation of the organ 

 perceiving violet is then increased. The white of the red-blind is natu- 

 rally a combination of their two primitive colors in a determinate pro- 

 portion, a combination which appears blue- gray to the normal sight; 

 this is why he regards as gray the spectral transitition colors from green 

 to blue. Then the other color of the spectrum, which they call l)lue, pre- 

 ponderates, because indigo-blue, though somewhat whitish, according 



