Evening Republican, Volume 14, Number 88, Rensselaer, Jasper County, 13 April 1910 — DO YOU SEE RED? [ARTICLE]

DO YOU SEE RED?

What the World Looks Like to Mwfe tltudoa of Color Blind. Color blindness is far more common than is generally supposed. It has been estimated that about fifty-three people out of every 100 are either positively color blind or are suffering from what Is called “feeble color sense.” A man who can make out six of the seven colons in a rainbow has excellent color vision. If four, his color sense is feeble. If three or less, he is color blind. There are several sorts of ‘ color blindness, London Answers says. Some people are absolutely blind to coler, so that they see everything in one neutral tint, just as in a photograph, but the commonest sort is “red-green” blindness. A man afflicted with redgreen blindness cannot distinguish between red and green. He will take certain hues of green for the corresponding shades of red. The other shades of green he will call white. The colors that - a man of nonnal eight calls red, orange and yellow seem to him red, pale red and a still paler red. Color blindness has nothing whatever to do with acuteness of sight. In fact, it often happens that men who are blind to color have exceptionally acute sight. Sometimes a -man is color blind in one eye and not in the other. A man 'has been known, when blindfolded over one eye, to call a half sovereign a sixpence, though when the bandage was taken off he recognized the coin perfectly. , If red and green are the most difficult colors to the color blind, and if color, blindness is so general, it may seem strange that these should be the colors chosen for railway signals and for signals at sea. But it cannot be helped. Yellow and orange, when seen through a fog, look too much like white. A blue glass lets through only one twenty-fifth of the light behind it. Red, on the other hand, transmits light easily, and green is the only other vivid color possible. Naturally, as millions of lives daily depend on the sea and railway signals, every -man who wishes to obtain the responsible post of signalman, engine driver or ship’s officer has to undergo a thorough test of his sense of color. So important is the matter that recently the board of trade sent on a Special voyage in their own yacht a ship’s mate who had failed in the examination three times and passed it three times, in order to settle finally the question of his ability to distinguish colored lights at sea. The ordinary board of trade test, which has been adopted by most of the railway authorities, is with colored wools. On a white cloth or white taper a pile of tangled skeins of Berlin wool is laid. No two are of the same color as the test skein, and as close to it in shade as possible. He is not allowed to hold several in his hand at once and compare them. Each one he lifts he must eltner put back or lay beside the test skein. To avoid delay and to make sure that every candidate understands what is to be done, the examiner gives his instructions to all the candidates at cnce and keeps them in -the examination room together, watching and waiting their turn. The really color blind, however, usually give themselves away at once. This test over, the candidate has to choose between colors held up fifteen feet off. Lastly, he is given three skeins of vivid colors and asked to match them. Formerly candidates were tested with colored lanterns. One railway has a test of its own. The candidate looks along a tub and tells the names of the colors he sees on an illuminated revolving disk at the far end. It Is not generally known that a man may become temporarily color blind; in fact, excessive tobacco smoking may cause this infirmity.