He shook his head, and sighed into his beer. "I got fired, Casey," he confessed. "Over that there Killicut caper. Those plans--I might of known." He shook his head again like a tired old man. A shiver ran over me. "Here it comes," I thought. "What about those plans?" I asked. "Weren't they all O.K.?" He sighed again. "Nope. Oh, the plans was O.K. They was strictly bona fide. Only they won't work on Earth. I told 'em about that anti-grav in the first place. Then I almost caused an inter-world incident stealin' the Killicut Emeralds. And now the damn thing won't work on Earth!" He set to chewing his lip and staring into his beer. I took him by his scrawny shoulder and shook. "Why won't it work?" I yelled. "I knew there was something, the way she laughed! Why won't it work?" He stared dully at me. "Laugh, did she? Well, she sure had the last laugh. It won't work in our atmosphere; just on a chlorine or methane planet. It works like the poles of a battery. That Great Red Spot is just the negative pole. All those there plants change the atmosphere just enough to make it a strong negative field. Then all they have to do is counter-balance that with enough positive, and there they are. It works like anti-gravity, only it ain't. Only we ain't got an atmosphere we can work that way. Cripes! So she laughed!" His hoarse voice stopped and he stared bitterly at the wall. Then he cussed for two minutes without stopping. He took a big swig of that rotten beer. "I'll bet she's laughing herself fat, the old rip!" Well, I hope she is. In the dead of night sometimes I can hear her; and pretty soon I'm laughing, too.... End of the Project Gutenberg EBook of Jupiter's Joke, by A. L. Haley