Although the observer was not able to see the very thin layers of cloud overhead that would be required to account for the sharply defined shape of the saucers, he concluded that his explanation was the most reasonable one[XII-10]. In the Norfolk sighting, unfortunately, the witnesses could not easily have remained in one place to watch for a possible reappearance of the UFOs. If they had circled and flown back, and had been able to find the exact location, they might have seen the disks again. _The Tombaugh Rectangles_ A remarkable phenomenon observed in New Mexico in the summer of 1949 has remained among the most puzzling of the Unknowns. As in the Chesapeake Bay case, the facts are not in dispute. The witness was an astronomer, Clyde Tombaugh, at that time in charge of the optical instrumentation of the rocket-firing program at the White Sands Missile Range. He had had thousands of hours of experience in observing the night sky and when still a student had gained fame, after months of patient searching of photographic plates, by locating the image of the planet Pluto near the position long predicted for it by Lowell and Pickering. On the night of August 20 Tombaugh was sitting with his wife and his mother-in-law in the yard of his home in Las Cruces, watching the stars. There was no moon, and the transparency of the sky was extraordinary, so that even the stars of sixth magnitude, usually barely detectable by the naked eye, were clearly visible. About 10:45 P.M. a geometrically spaced group of six to eight rectangles of light appeared almost directly overhead. Of low luminosity, they were “windowlike” in appearance and yellowish-green in color. The individual rectangles were quite small, not wider than four or five minutes of arc, and the entire group covered a span of about 1 degree (about twice that of the full moon). As they moved noiselessly in a vertical circle path toward the south-southeast, the individual rectangles became foreshortened, the span of the group became smaller, the lights turned brownish and faded from view when 35 to 40 degrees above the horizon. They had been in sight for about three seconds. Mrs. Tombaugh, who did not see the lights until they had moved some distance from the zenith, observed them for only about 1½ seconds before they disappeared. To her they seemed a diffuse greenish glow, interconnecting a span of greenish spots of light. Her eyesight had always been less acute than that of her husband, and they attributed the difference in their descriptions to this difference in vision.