ACCIDENTS BY RAIL AND SEA. 



153 



light, but it is the white (gray) of the green-blind, for it is composed of 

 almost equal parts of the two primitive colors. 



The blue is an intense violet, but a little less "saturated" than indigo, 

 which is more strongly luminous and more *' saturated." Violet is a little 

 less intense, but more "saturated" than normal violet. The tints most 

 luminous and at the same time most "saturated" which must constitute 

 the types of the primitive colors of the green-blind are orange or its im- 

 mediate neighbor in the spectrum, red, and indigo-blue. Now orange is a 

 color which, in ordinary language, especially amongst the uncultivated 

 and uupracticed, is indiscriminately called red and yellow; this fact 

 explains why the green-blind denominate their first fundamental color 

 sometimes "red " and sometimes "yellow." We will add to this descrip- 

 tion the same remark made about red-blindness. In green-blindness 

 the same organ is also found affected by spectral red and green light. 

 Eed and green are then perceived by the green-blind in the same way, 

 or, in other words, are to him in fact exactly the same color. In cases 

 where he succeeds in distinguishing them, it is by the aid of the inten- 

 sity of the light ; but with regard to this intensity of light, it is the op- 

 posite of what occurs in the case of the red-blind. A green tint which 

 to the green-blind must appear exactly like a red one, to a normal sense 

 of color must be sensibly more luminous than red. This is shown by 

 the dotted vertical lines between R. and O. and also between Y. and G. 

 (fig. 3), and is confirmed in every respect by experience. 



3. Violet-blindness (or blue according to Maxwell) is due, according 

 to the theory, to the absence or paralysis of the elements perceiving 

 violet. The two primitive colors of the violet-blind are then, according 

 to theory, red and green. The spectrum of the violet-blind must in conse- 

 quence be represented as follows : 



Fig. 4. 



The red is a purer red color (not yellowish) than normal red, but still 

 less "saturated"; the more it inclines toward orange the more strongly 

 luminous it is, but is at the same time less "saturated," more whitish. 

 The yellow is, as it were, a combination of almost equal proportions of 

 the fundamental colors that form white. Green is a strongly luminous, 

 but whitish green, which in tending toward the blue, becomes more and 

 more " saturated," so that greenish blue must be the type of these hues. 

 The blue is a green of moderate luminosity and strongly " saturated", 

 and violet is green very feebly luminous, but also "saturated" in a much 

 higher degree than the normal. A violet strongly luminous is suflBcient 



