Air Force investigators arrived that afternoon. They had already received many reports that a brilliant fireball had flashed through the sky at 4:25 A.M., the time in question, and had been observed by many witnesses in the area between Washington, D.C., and Pittsburgh, Pennsylvania, but no fireball could account for the ground light. The next morning at 5:15 A.M. an intensely white, fluctuating light was observed at the same place and was studied through binoculars until daylight made it invisible; it could be seen only from the west side of the mess hall, and one step to the right or left would hide it from the observer. Traveling toward the position of the unknown, investigators found a dairy barn three miles away, and on a direct line of sight from the place the UFO had been observed. On one end of the barn was a 200-watt floodlight with a white reflector, still burning. On questioning the farmer, they learned that until recently the light had been burned out and had not been in use. The early hour of sunrise during the summer had provided all the light he needed to milk his cows. With the shorter days of autumn, however, he had needed the light and had replaced the bulb only a few days before. On the morning of the sighting, he had turned on the light a few minutes before the sergeant had noticed it[XII-1]. Thus several unrelated factors had combined to produce the illusion of a landed space vehicle: 1) only a week earlier, newspapers had publicized the alleged landing of a flying saucer in Sheffield Lake, Ohio (see _Chapter_ XIII); 2) a brilliant fireball had appeared; 3) a farmer had turned on a floodlight, previously out of use for several months; 4) the meteor had disappeared and the floodlight had appeared in roughly the same position as viewed by the observer. _The Problem of Unknown Lights_