ACCIDENTS BY RAIL AND SEA. 173 



the principle of the difference iu the quality of light, that is to say, on 

 color, but because, iu the applicatiou, the very colors have been choseu 

 which iu practice are the best adapted to the object in view. Expe- 

 rience also seems to have decided in favor of this system, since in spite 

 of the substitutes proposed with a view to retain the color-blind, it has 

 up to the present time maintaiued its ascendency, so to speak, through- 

 out the entire v.orld. 



3. — DISMISSAL OF THE COLOR-BLIND. 



It now remains to solve the question of what reform is preferable. Is 

 it necessary, in order to facilitate the free admission of all classes of 

 color-blind to the service of railways, to change a system of signals 

 recognized as the best and generally accepted, or, continuing the system, 

 to discard the incompetent? It is manifest, from what we have just said, 

 which measure is most conducive to the safety of railway lines. All 

 depends upon knowing whether, from solicitude for the color-blind, any 

 measures tending to diminish systematically or on princi[)le this security 

 should be countenanced. We are fortunately accustomed to accepting 

 the maxim that private interest must yield to the general welfare. The 

 l)roportion of color-blindness in the population of a country is relatively 

 very small. It is true that railway employes are not made for signals, 

 but the signals for them ; yet it is no less certain that in this matter the 

 first consideration must be the public good, and not a personal advan- 

 tage. It is, without doubt, very praiseworthy to desire that any one 

 afflicted with a congenital defect, for which he is not responsible, should 

 not be debarred trom entering every career open to those more favored by 

 nature. But this case is not peculiar, for there are many other careers 

 to which every one has not access for want of the natural ability requi- 

 site for the efUcient discharge of the duty 5 and there' are numbers of 

 persons who, in consequence of some natural defect, cannot be admitted 

 into even the most common occupations. We will, therefore, maintain 

 the position that, as long as the existing system of signals used on rail- 

 ways is considered in almost all respects the best known, it is indis- 

 pensable that no one incapable of rapidly and accurately distinguishing 

 red, green, and yellow should be allowed to fill any position on railways 

 involving any connection with colored signals. 



IV.— GENERAL PRINCIPLES AND PLAN OF CONTROL OF 

 THE CHROMATIC SENSE. 



It is, of course, to the interest of railways not to take into their ser- 

 vice persons having any degree of defect in their chromatic sense. It 

 must be acknowledged that in several posts on railways, the observation 

 of signals is not considered an indispensable requisite ; but as it is, at least, 

 unfortunate to have an employ^ who can not, in case of need, attend to 

 the signals, we consider this reason alone as quite sufiicient. For no one, 



