"Don't know!" Freddy choked through the smoke. "Can't understand it. Just happened to look back in here to check if anything had been hit, and found the whole blasted place full of smoke. Saw a couple of stabs of purple light, and then the whole business broke into flame. Didn't dare waste time calling you. Think the fire got the inter-com wires, anyway. Boy! Suppose I hadn't happened to look in here!" Dawson simply shuddered and dragged another sack off the pile. He didn't bother to make any comment. It was horrible enough just to think about the whole rear end of the Fortress catching fire. Besides, there was too much of the stinging smoke in his nose and throat to permit any unnecessary talk. They still weren't out of danger. No, not by a jugful. At that very moment, as Dawson kicked a smoking sack toward the bomb-bay opening, a tongue of purple white light shot out of its heavy canvas covering. A hissing sound filled Dawson's ears, and then the mail sack went tumbling down through the air. Dave's breath seemed to stick in his throat, and his heart turn to stone, as the terrible realization came to him. He heard Freddy Farmer cry out in stunned amazement but he could not have turned his head Freddy's way at that moment, even if not doing so had cost him his life. Half frozen with fear, he stood gaping at the bomb-bay opening down through which the flaming mail bag had just disappeared. Then, snapping out of his trance, he whirled around and practically threw himself at the three or four smoking mail bags left. Fire burned his hands a little, but he hardly felt the pain. His only thought at that moment was to get every last one of those mail bags out of the plane. And a few moments later the last one of them went spinning down through the opening out of sight. By then an up-draft had cleared away most of the smoke. For a moment Dawson and Freddy Farmer stared at each other in the pale glow of a single bulb in the compartment ceiling that had not been reached by the flames. Then, as though still in a trance, Dawson reached out and pushed the button that closed the bomb-bay doors. And then the two of them more or less reeled back to the pilot's compartment and dropped gasping for air into their seats. "The first aid kit, beside you, Freddy," Dawson finally managed to force the words from his lips. "Better get it out and use some of the tannic jelly on our hands. No sense taking chances. Good grief, Freddy! There were time fire bombs in some of those sacks. Somebody figured to make us bail out, and flame this thing down onto the deck!"