RAILWAY ACCIDENTS 249 



recognition of colors at night by any man, above all by a man who has 

 many and most insistent duties besides. 



That the color-sense is wholly unfit for the office it holds in rail- 

 roading is hardly open to any doubt whatever. One must speak with 

 less assurance, however, as to what should take its place. But even 

 here the general principle that might guide the change is reasonably 

 clear. Our eyesight detects two different features in objects — their 

 color and their spatial character, such as shape, position and move- 

 ment; and the sense of color is far less primitive and vital and mascu- 

 line than is the rude sense of space. Nature seems to have held the 

 sensitivity to color a cheap and slighted accomplishment, to be crowded 

 out or postponed to the mere finishing school, like young ladies' French 

 and dancing. But the rugged feeling for place and direction is early 

 given and pressed deep until it becomes a central fact in self-preserva- 

 tion and advance. 



Now if the eyesight of the engineer is to be depended upon at all, 

 it is this more fundamental and stable portion of it that should be given 

 responsible work. If the practical difficulties could easily be met, the 

 power to distinguish between rest and rapid movement of some con- 

 spicuous object would be the best to call upon in signaling. For we, 

 like the bird and beast in the woods, are alive to slight quick move- 

 ments in the field of view, far more than to color or even to shape and 

 size. When the arms are waved or a lantern swung by hand to attract 

 attention, appeal is instinctively made to this deep and primal interest 

 in moving things. But next to this, the simplest and least erring of 

 our visual perceptions is of large differences like that between a ver- 

 tical and a horizontal line or one aslant. Now these rough and simple 

 elements are precisely those used for the day signals of most block 

 systems, where there is an extended arm placed high beside the track, 

 and its direction of pointing — up or down or at some angle inter- 

 mediate to these — tells the engineer whether the track ahead is open 

 to him or closed or to be entered only with caution. Such signals 

 make no prime appeal whatever to the sense of hue, but only to the 

 sober feeling for visual place. And there seems to be nothing to 

 prevent that this same principle of signaling should be carried over 

 into the night and be even more successful there. For the extended 

 vane used for the day signal often is before some unpropitious back- 

 ground of buildings or of trees against which it stands out in no strong 

 relief. But at night it would be possible to use some self-luminous line 

 of light that would appear sharp and unmistakable against the dark. 



The detailed mode of applying such a general principle belongs to 

 mechanical art rather than to psychology. But lest the principle itself 

 should be misjudged for want of some more definite form in the mind, 

 it might be well to imagine a row of incandescent lights inserted in 

 the signal-arm now used by day, but lengthened and otherwise modi- 



