"Well, I can't give you a scientific answer to that one," Dave said. "But Saint Elmo's Fire is the name given to globular electric light often seen on the spars and rigging of ships at sea during a storm. And of recent years it has been seen on the wing tips of airplanes flying through electrically charged air. Frankly, I've never seen any of the stuff in my life. But I knew a pilot once who used to fly over the Andes in South America, and he said they used to see it often. Little bright balls of fire that seemed to roll right along the leading edges of the wing, and then disappear just when you thought they were going to bump into the gas tanks, or something. The first few times he witnessed such a display he lost a dozen years off his life. He said, though, that after a while he got used to it--even looked forward to it every time he took off." "You're pulling my leg!" Freddy snorted. "No, Farmer, that's true," Colonel Welsh said. "I've seen some Saint Elmo's Fire myself. And I can tell you that it scares the pants off you the first time you see it. Ever fly through a thunder storm, and see lightning playing around your wing tips?" "Yes, I've seen that," Freddy admitted. "And I was sure I'd never live to land safely on the ground again." "Well, then, you know how it feels to see Saint Elmo's Fire," the Colonel chuckled. "Only I think the Saint Elmo stuff gives you a worse scare when you see it actually come rolling along the wing toward you. But that light I saw just now wasn't shaped like a ball. More like a streak, or like the powdered tail of a comet. It was strung out in a--" If Colonel Welsh finished the sentence, nobody heard it. At that moment the night skies shook and trembled with the savage yammer of aerial machine gun fire. And the cabin window not eighteen inches in front of Dave's eyes seemed to crack in a trillion places and then melt away into oblivion. "My word!" Colonel Welsh cried. "What was that?" Dave didn't bother to answer for a second or so. His heart had zoomed up his throat to jam hard against his back teeth, and his eyes had bulged out of their sockets like marbles on sticks. Instinct took split second charge of his movements, however, and almost before he realized what he was doing he had booted the Lockheed up over on left wing tip and was slicing down through the air. At practically the same instant he whipped out his free hand and switched off the navigation lights. Then as the craft went slicing down through the night sky, he dragged air into his aching lungs. "Those were aerial machine guns!" he cried. "And whoever was working them was in earnest. Look at that window! Just a shade improvement on his aim and it would have been curtains for the three of us." As the last left Dave's lips, he pulled the plane out of its wild sideslip and went curving up and around to the left. "Aerial machine guns?" Colonel Welsh echoed in blank amazement. "You're crazy, Dawson!"