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Page:Popular Science Monthly Volume 72.djvu/65

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of the semaphore signal. A writer in Pall Mall, 1902, thus describes the extension of the signal system:

However, as traffic increased, fixed signals, first of the disc and then of the now universal semaphore pattern, were introduced, and worked by hand—that is, by means of a handle at the foot of the post. The idea of manipulating a cluster of these signals, together with track switches, was suggested by the inventive genius of a lazy Irish porter. The latter had two signals, some distance apart, to attend to; and in order to save himself the walk, he counterweighted the handle of one, and tied to it a length of clothes-line. Thus while standing at the one he was able to operate the other. An inspector chanced to see the rude though efficient mechanical device, and ordered some experiments on the same principle to be carried out in Camden goods yard—for the incident occurred on the North Western Line—with the result that the system of actuating signals from cabins or boxes by means of levers and wires was introduced. The first arrangement of concentrated levers equipped with an interlocking apparatus was invented in 1843.

The entire question of working a double-track road and its signals, and especially of a left-hand road, depends upon general right-handedness, etc., particularly upon right-eyedness, and more than all else upon the fact that the driver or locomotive engineer sits or stands upon the right-hand side of his boiler or cab. The factor that has been utterly overlooked, by writers, by railway managers, by everybody connected with or interested in the problem, is that the engineer stands or sits where he does simply and solely because he is a right-eyed man. It is all as easily demonstrated as the existence of right-eyedness by the experiment with a pencil: Hold up a card or blotting sheet so that the left eye is covered by it and the right views the scene or landscape; then suddenly move the card so that the right eye is covered by it and the left eye is the used one. At once the whole scene "jumps," intermediate objects are in an entirely different relation to those more distant, there is doubt and uncertainty of localization, there is discomfort, and a clear desire and attempt to get the right eye into use. Look at moving objects and the troubles are increased; ride in the engineer's cab and they are doubled again; when sitting on the left side and looking out of the left-side window, it is necessary to put the whole head, that is, the right-eye, out, in order to be sure about the approaching objects, signals and their relations. Sit on the right side and at once it is recognized that it is only the right eye that need be put outside the window in order to see correctly and to satisfy the mind. It is most curious and of absorbing interest to see how this fact was slowly, unconsciously, blindly recognized, but without ever being uttered or brought to consciousness in the history of locomotive-engine building and early railroading. If you ask any railway official or chief engineer of a modern railway why the engineer sits on the right-hand side of his cab, disusing his skilled and strong right hand