Page:Popular Science Monthly Volume 26.djvu/450

434 Manager, Mr. Pugb, as its chairman, to whose keen interest much of its success is now due.

The magnitude of the task then began to appear, when the forty or fifty thousand employés of five thousand miles of track, with their ten or twelve thousand men actually dependent upon signals of color for their guidance, of whom four per cent might be color-blind, and ten per cent so defective in visual power, for form and hearing, as to render them dangerous, arose before the imagination. To have adopted the method of Holmgren for the color-sense, by which an accomplished ophthalmic surgeon would conduct the examination of each man, would have demanded years of his entire time, would have been so tardy as to allow large additions to the force before it could be accomplished, and was soon rejected as impracticable; neither was it thought possible to train a sufficient number of the company's surgeons to perform this special task with fairness to the men and safety to the company. To secure the co-operation of the employés the officers needed a system that could be applied locally on each division, quietly and confidentially, and at the convenience of the men, without compelling them to lose much time. Any undue publicity, or inexorable law that would compel the summary discharge of from ten to fifteen per cent of their trained operatives, would have disorganized the service, and destroyed the discipline of the company; and for their own protection, and as a duty to the public, the officers were willing to put on trial any practicable scheme, without the pressure of any overanxious public opinion or hostile legislation.

These, and other considerations of weight, led the writer to the invention of an instrument for the examination of the color-sense, which could be efficiently used by any intelligent, instructed official, and a record of it permanently kept for the information of the officers, and as a guide for the action of any surgical expert whom the road might appoint to superintend the entire system. This consists of forty skeins of wool, each one attached to a movable button, having figures from 1 to 40 inscribed on them, suspended from two flat sticks, so arranged that the numbers are concealed. Holmgren's method of matching colors is adhered to, and the test-colors to be matched are green, rose, and red: the skeins from 1 to 20 being used for green, those from 21 to 30 for rose, and from 31 to 40 for red; upon the odd numbers are suspended green, rose, and red skeins; upon the even ones those "confusion colors" which the experience of the writer had taught him would be the most likely to be selected by the color-blind. In its use a green skein is placed before the person at a few feet distant, and he is directed to select those of that color from the stick, and to turn them away or throw them over; then the rose, then the red; and as this is done for each test-skein, the numbers upon the buttons arc inspected and recorded upon a blank. So simple is this system that the division superintendent, who is responsible for the examination, may forget