It brought the first laugh. Hoose had a drawling manner of speech which sometimes caused the men in ranks some discomfort to keep their faces straight. We were more relaxed than we had been, for we appeared to be in no danger. Besides, we were extremely well armed. If anybody attacked us--but I refused to think too much about that. I had a sneaking hunch that our top-secret weapons were, in this place, just so much metal, value zero. * * * * * Now and again, during a comfortable afternoon, I sent out patrols to check on the invisible wall. They always found it. Either it was there continuously, or it was dropped when nobody was near and hurriedly restored when a patrol went out to check. The feeling that everything we did or said was noted and heard began to make us wary of movement and speech. We tried to pick out vantage points from which we could be seen. Any one of the dunes outside our prison might have hidden something. But discussing it, none of us felt that this was up to the standard of behavior of whatever it was that held us. That's about as far as we got before the sun went down with startling suddenness and darkness settled over our Limbo. The darkness was impenetrable. It lasted perhaps an hour. Then a sort of haze seemed to withdraw in all directions, inwardly and outwardly--and the wondrous tropical sky, studded with stars that hung down almost within reach of human hands, bathed our upturned faces. In silence we all watched. There was an unusual coolness in the air, too, for several minutes, Cuba, at that time of the year, was almost never cool, even late at night; but some of the men were shivering. Sweat had not dried on all of us, and sweat is bad when you are motionless, at night. I was about to order the men to exercise a little, when I realized something that Hoose put into words first: "Now," he said, "they're feeding us warmth, just as they feed and water us! And we've been here for hours and don't have any idea, even, who or what they are!" Nobody else said anything. All the rest of us were studying the sky. "I don't see the Big Dipper!" said Sergeant Eckstrom. "Nor the North Star!" somebody added. "Nor Venus, nor Lyra!" said someone else. "I've been studying our books on constellations, and I don't recognize a one! _Where are we?_ We're not even in Cuba! Not even in the Northern Hemisphere! Not even--" "Not even on the Earth--?" said Hoose. It was just here that the whispering began in our walkie-talkies; whispering like nothing we had ever heard. We could make out nothing that sounded at all like human words. The sounds were mechanical, yet not-mechanical. I've called them whispers only because that comes closest to describing the eerie sounds which every last one of us was now hearing in his walkie-talkie. "It's vibration on our wavelength," said one of the gobs. "But that's the best I can say of it." "Morse? International?" I asked. But nobody could offer an answer.