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Show m an tmrpse oi a v-ncie. Occasionally the light would start apparent motion after the subject had stared no more than six seconds. sec-onds. The movement is called autokinet-ic autokinet-ic illusion. ' The cause is hot certain. cer-tain. It may occur because of streaming of fluids in the eyeball. Night fliers got this illusion from: following the single tail light of a plane ahead. They had a better chance to escape the hobgoblin than the observers in laboratory experi-. ments, for, frequently, stars or other tail lights were visible. View of a second light acts as a check on the illusion. Twin Tail Lights Help. However, certain features of night flying in tight formations tend to distract dis-tract a pilot's attention from seeing anything except the tail light of one plane ahead. He may have to judge his distance dis-tance from this plane by its tail light alone, by noting the size of the light, which would seem to grow smaller with increasing distance,' and by its brightness, which similarly simi-larly changes. Both types of changes are difficult to gauge with accuracy, and the view is complicated by haze, which' causes a nearby tail light to appear, farther away, both in size and in; brightness. Among the remedies are twin tail lights. In addition to curbing illusions, illu-sions, their apparent spread apart changes definitely with the change in distance from the watching pilot. This change in spread is an accurate gauge of distance. Furthermore, the change is not affected much by size or brightness of the tail lights, nor by haze. Prof. Miles suggests that twin tail lights on planes will have more than military use, being good safety factors in commercial and private flying, and an aid in reducing pilot fatigue. If Stars Roam, It's Your Eyes Trick of Human Sight Has Caused Death of Pilots In South Pacific. . NEW HAVEN, CONN. When you stare at a single, distant light at night, and it seems to start moving around, don't jump to the conclusion that someone is carrying it. If the light seems to zigzag high up into empty space or swing left and right like a great pendulum, don't suspect sus-pect spooks. You are seeing a trick of human eyes, one that has killed some airplane air-plane pilots in the South Pacific and was first reported in 1799 by the astronomer Von Humboldt when a star he was watching seemed . to wander around. Yank, the army weekly, discloses the South Pacific deaths and reports re-ports that the mystery was solved and that remedies were applied. The explanation of what happened is furnished in the records of Dr. Walter Wal-ter R. Miles, professor of psychology psy-chology at Yale university. 65-Degree Motion. After Von Humboldt's wandering star discovery, numerous laboratory experiments in looking fixedly at a single, faint light in total darkness revealed some amazing effects. For some persons the light moved as much as 65 degrees, more than a sixth of the distance around the horizon. hori-zon. Even the smaller movements were around 20 degrees. Extreme fatigue intensified the apparent distances. dis-tances. The speed of movement of the, wandering light also was astonishing. aston-ishing. It ran from two to 20 degrees de-grees a second. One degree is about twice the diameter of the full moon against the sky. The light sometimes went up and down in a zigzag course, but more |