Mill Valley, California: Taxi owner sees iridescent balloon-like object shrink and vanish

At 7:15 p.m. on August 14, 1952, taxi owner Bob Robertson looked up while painting his house in Mill Valley, California, and saw “a large transparent balloon-like object” that was “iridescent like a soap bubble.” The object hovered motionless before it shrank to the size of a teacup and vanished entirely. His wife also saw it, but it disappeared before neighbors could get outside. Robertson estimated it was visible for about a minute and a half and speculated it might be “an air or gas pocket formed by diving jet planes.” The account follows the entry in George M. Eberhart's chronology UFOs and Intelligence (CUFOS) and the sources cited there; it is not an independent determination by From Beyond Space.