When the pilot was informed that he had been fighting a lighted weather balloon, released that night from the Naval Air Station at Guantánamo Bay, he may very naturally have felt incredulous. Instead of arguing, however, he helped carry out an experiment. On the following night the station released another lighted balloon, at about the same time, and the pilot took off to try an intercept. After comparing the experience with that of the night before, he concluded that he had indeed fought a balloon: “Many of the illusions seen on the previous night could be duplicated by maneuvering the plane appropriately. I tracked the balloon to 12,000 feet and made runs on it from as far away as ten miles. I could always intercept and pass it at any predetermined position, as against the fact that I could not get close to the other light, which at the time appeared to be moving away at each attempt at approach.” There were other differences, too. The rate of ascent was faster on the first night, and the second balloon did not exhibit a tail. Discussion with members of the Aerology Department brought out the explanation of these differences. The first night had been clear, with a bright moon that transformed the accompanying light into a flickering tail. On the second night the dew point was higher and the atmosphere was hazy so that no tail was visible, the balloon looked smaller, and showed an orange glow instead of a bright white. The rapid climb of the first balloon could be attributed to a vertical air current, or to an air layer of variable density, or both. A balloon often develops leaks at high altitudes and then descends to an intermediate altitude where the loss of gas and the denser atmosphere cause it to hover. One wind balloon, released earlier from the same base, had developed a leak, started spinning, covered a horizontal distance of about a mile, and then dropped into the water. Similarly, the first balloon probably developed a large hole and fell very rapidly for a while until the loss of gas and the increase in atmospheric pressure caused it to shrink and close the hole, slowing its descent. Some of his impressions, he decided, were the result of making tight turns at high speed: “The last fast descent could be due to the fact that I may have cut the balloon with my prop on the third run, causing the light to fall free. My last three-quarter turn was diving to port in a position northeast of the light, which could have produced the illusion of the light arcing across Caimanera and the Bay and settling into the water. The light’s crossing from starboard to port could have been the result of my plane being in a vertical turn and the light descending straight down instead of going horizontally. At the time of intercept I thought my wings to be almost level, the light traveling in a flat circle, but due to the afore-mentioned vertigo, a pilot cannot rely on his senses to establish attitude.”